# paper.pdf ## Metadata - PDFFormatVersion=1.7 - Language=en-US - IsLinearized=true - IsAcroFormPresent=false - IsXFAPresent=false - IsCollectionPresent=false - IsSignaturesPresent=false - CreationDate=D:20260625182425+05'30' - Creator=Adobe InDesign 19.5 (Windows) - ModDate=D:20260625182431+05'30' - Producer=Adobe PDF Library 17.0 - Title=Loss to follow‐up in patients diagnosed with or treated for low‐ and high‐grade squamous intraepithelial lesions: A comparison of general practitioner‐ and gynecologist‐led surveillance - Trapped=False - Custom.WPS-ARTICLEDOI=10.1111/aogs.70301 - Custom.WPS-JOURNALDOI=10.1111/(ISSN)1600-0412 - Custom.WPS-PROCLEVEL=3 - jav:journal_article_version=VoR - prism:doi=10.1111/aogs.70301 - pdfx:wps-articledoi=10.1111/aogs.70301 - pdfx:wps-journaldoi=10.1111/(ISSN)1600-0412 - pdfx:wps-proclevel=3 - dc:title=Loss to follow‐up in patients diagnosed with or treated for low‐ and high‐grade squamous intraepithelial lesions: A comparison of general practitioner‐ and gynecologist‐led surveillance ## Contents ### Page 1 Acta Obstet Gynecol Scand. 2026;00:1–8. | 1wileyonlinelibrary.com/journal/aogsReceived: 4 March 2026 | Revised: 7 May 2026 | Accepted: 15 June 2026 DOI: 10.1111/aogs.70301O R I G I N A L R E S E A R C H Loss to follow-up in patients diagnosed with or treated for low- and high-grade squamous intraepithelial lesions: A comparison of general practitioner- and gynecologist-led surveillance Lieke van de Kam1,2 | Albert Siebers3 | Ruud Bekkers2,4,5 | Dennis van Hamont1 |Jurgen Piek4This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made. © 2026 The Author(s). Acta Obstetricia et Gynecologica Scandinavica published by John Wiley & Sons Ltd on behalf of Nordic Federation of Societies of Obstetrics and Gynecology (NFOG).Abbreviations: CIN, cervical intra-epithelial neoplasia; HrHPV, high-risk human papilloma virus; HSIL, high-grade squamous intra-epithelial lesion; LLETZ, large loop excision of the transformation zone; LSIL, low-grade squamous intra-epithelial lesion.1Department of Obstetrics and Gynecology, Amphia, Breda, the Netherlands2Grow Research Institute for Oncology and Reproduction, Maastricht University, Maastricht, the Netherlands 3Palga, Dutch Pathology Registry, Houten, The Netherlands4Department of Obstetrics and Gynecology and Catharina Cancer Institute, Catharina Hospital, Eindhoven, The Netherlands 5Department of Obstetrics and Gynecology, Radboud University Medical Centre, Nijmegen, the NetherlandsCorrespondenceLieke van de Kam, Department of Obstetrics and Gynecology, Amphia, Molengracht 21, 4818 CK, Breda, The Netherlands. Email: lvandekam1@amphia.nlFunding informationAmphia Science Fund, Grant/Award Number: 2023-1- 008; Incentive Committee Catharina Hospital, Grant/ Award Number: 2309 – EFFECTUATEAbstract Introduction: Cervical carcinoma can be prevented by treating precancerous lesions, which are classified as low-grade (LSIL) and high-grade (HSIL) squamous intraepithe- lial lesions. Follow-up of patients diagnosed with LSIL or treated HSIL is typically con- ducted in secondary care by a gynecologist. However, this may also be conducted in a primary care setting at the general practitioner. This latter approach offers potential benefits such as lower healthcare costs and care closer to home. However, the effec- tiveness of follow-up by general practitioners is unknown.Material and Methods: This retrospective cohort study included patients diagnosed with LSIL or treated HSIL by the gynecologist, with no prior history of SIL or cervical cancer, who either underwent cytological follow-up at the gynecologist or the general practitioner. The primary outcome was loss to follow-up at 12 months for LSIL and 24 months for treated HSIL.Results: A total of 691 patients were followed up by the gynecologist, and 1172 by the general practitioner. In the LSIL group, 38.1% (333/874) of patients followed up by a general practitioner were lost to follow-up at 12 months, compared with 16.6% (92/554) of those followed up by a gynecologist (p < 0.001). For treated HSIL, 44.3% (132/298) were lost to follow-up at 24 months in the general practitioner group, ver- sus 24.1% (33/137) in the gynecologist group (p < 0.001).Conclusions: Follow-up by a general practitioner after a diagnosis of LSIL or treated HSIL is associated with nearly twice the rate of loss to follow-up compared to follow-up by a gynecologist. ### Page 2 2 |van de KAM et al.1 | I NTRO D U C TI O NCervical carcinoma is the fourth most common cancer in women worldwide and a substantial contributor to cancer-related mor- tality, especially in middle- and low income countries.1 Cervicalcarcinoma can be prevented through screening, which generally involves collection of cervical material for testing on the presence of high-risk human papillomavirus (hrHPV) and cytology to de- tect precancerous cervical lesions.2,3 A significant decrease in the prevalence of cervical cancer following the introduction of screen- ing programs has been observed.4 Patients with abnormal cervi- cal cytology have an indication for colposcopy. During colposcopy biopsies can be obtained for histological evaluation to determine presence of low- or high-grade cervical disease. Cytologically, low-grade (LSIL) and high-grade (HSIL) squamous intraepithelial lesions classify abnormalities detected in cervical screening. Histologically, an LSIL diagnosis corresponds to CIN1 (cervical intraepithelial neo- plasia), while an HSIL diagnosis includes both CIN2 and CIN3, ac- cording to the LAST Project terminology adopted in the United States. In Europe, the CIN1-3 classification remains widely used for histological grading.5 In the present paper, we use LSIL/HSIL terminology for both cytologically and histologically identified le- sions. A diagnosis of LSIL after colposcopy is usually followed by re- peated cytology and hrHPV testing for surveillance. Management of HSIL includes three options: an expectant approach with repeat cytology and hrHPV testing, a surgical approach using large loop excision of the transformation zone (LLETZ), or a pharmacological approach with imiquimod.6 The choice of management depends on the patient's future wish to have children, given the increased risk of premature delivery following LLETZ.7 However, for CIN3, it is recommended to perform LLETZ or initiate treatment with imiquimod.8,9 Following surgical treatment, surveillance typically includes cervical cytology and hrHPV testing. The current Dutch national guideline for precancerous cervical lesions permits surveillance by the general practitioner, instead of the gynecologist, depending on the severity of the lesion.8 Since 2017, one hospital in the Netherlands has systematically been re- ferring patients back to their general practitioner for surveillance with follow-up cervical cytology and hrHPV testing, when appli- cable. This policy is communicated in writing to the general prac- titioner and both verbally and in writing to the patient. Shifting surveillance to primary care might reduce relatively expensive secondary care, strengthen regional collaboration, and ensure that general practitioners maintain their knowledge and skills. Additionally, patients face lower costs and benefit from care closer to home. However, a potential risk is that patients may be lost to follow-up if the subsequent surveillance protocol is not properly followed. The safety of this model has not been studied before. Therefore, this study aims to evaluate the difference in loss to fol- low-up among patients diagnosed with LSIL or treated for HSIL when follow-up is provided by a general practitioner compared to a gynecologist.2 | M ATE R I A L A N D M E TH O DS 2.1 | Study design and populationA multi-centre cohort study was conducted in two non-academic teaching hospitals in the Netherlands. Surveillance by the general prac- titioner has been implemented at one hospital since 2017. Therefore, patients were included from January 2018 till December 2020. At the other hospital, surveillance is conducted by the gynecologist. Patients with abnormal cervical cytology (Bethesda system ≥ atypical squamous cells of undetermined significance [ASC-US]), ei- ther detected through population-based screening or diagnosed based on medical indication (e.g., postcoital bleeding), were referred to the gynecology departments of the including hospitals for colpo- scopic evaluation and, if indicated, biopsy or large loop excision of the transformation zone (LLETZ). The initial screening was performed every 5 years between the ages of 30 and 60 years by a general practi- tioner in case of population-based screening, and at any age by either a general practitioner or a gynecologist in case of medical indication. Primary hrHPV testing with cytology triage was standard practice during the inclusion period in the Dutch cervical cancer screening pro-gram.8 For women presenting with symptoms, cervical cytology was performed as part of diagnostic evaluation. Routine co-testing with hrHPV was not standard practice according to the Dutch cervical cy- tology guidelines. Additional hrHPV testing could be considered on clinical indication, but this was not part of standard policy. Inclusion criteria were a diagnosis of LSIL or HSIL treated with LLETZ. Exclusion criteria were patients under 18 years of age, a history of Human Immunodeficiency Virus (HIV), and history of LSIL, HSIL, adenocarcinoma in situ, or cervical carcinoma. Patients who were not referred back per protocol to their general practitioner on preference by the healthcare professional or patient, patients who were scheduledKey messageLoss to follow-up rates are higher when LSIL or treated HSIL is surveilled at the general practitioner versus at the gynecologist. Recurrence of cervical abnormalities is rare in both groups after short follow-up. A recall system may reduce loss to follow-up.K E Y W O R D Scervical intraepithelial neoplasia, follow-up, general practitioners, gynecology, patient compliance, primary health care, recurrence ### Page 3 | 3van de KAM et al.to return to their gynecologist but either independently opted for or were advised to receive surveillance by their general practitioner, and patients with treated HSIL who had an indication for follow-up at 12 months due to abnormal cervical cytology at 6 months follow-up were also excluded. Finally, patients who did not undergo follow-up cervical cytology due to all-cause mortality, hysterectomy, or reloca- tion during three-year follow-up period were excluded.2.2 | Follow-upPatients with LSIL were scheduled for surveillance cytology and hrHPV testing at 12 months, and those with treated HSIL at 6 months, followed by an additional check after 24 months after treatment when the 6-month cytology was normal. For general practitioner-based surveillance, cervical cytology was conducted at 12 months for LSIL and at 24 months for treated HSIL when 6-month cytology was normal. Once patients were referred back to the general practitioner for surveillance, this was communicated verbally and in writing to the patient, and in writing to the general practitioner. The letter received by the patient and the general practitioner included the results of the previous cytology, his- tology, and colposcopic impression, as well as the timing of the next follow-up appointment, specified in months according to the Dutch national guideline for precancerous cervical lesions.8 It is important to note that patients were responsible for scheduling this follow-up appointment themselves.2.3 | Data collectionPatients were selected from the hospital files, based on the International Classification of Disease (ICD-10) code “noninflamma- tory disorder of cervix uteri” and the start date of their first outpa- tient contact. Patients without colposcopy or LLETZ in the inclusion period, LLETZ before the inclusion period, or with a history of cervi- cal carcinoma were excluded. All other selected patients were as- sessed for eligibility by reviewing their electronic patient files. For eligible patients, characteristics such as age, smoking status, and colposcopic impression were extracted from their electronic pa- tient files and entered into an electronic case report form in Castor Electronic Data Capture.10 Data on cervical cytology, histology, biop- sies, LLETZ, and hrHPV test results were retrieved from the Dutch nationwide network and registry of histo- and cytopathology in the Netherlands (Palga, Houten, the Netherlands), where the two data sets were linked using probabilistic matching.11 Diagnosis of low-grade or high- grade disease was determined based on histology or, if histology was not available due to absence of biopsy or LLETZ, based on colpo- scopic impression. To ensure data reliability, a comprehensive quality check was conducted. All variables obtained from both the electronic patient records and the Dutch nationwide pathology database were manually reviewed and cross- checked for consistency. The data obtained from Palga are subject to strict access regu- lations. The participant data cannot be shared publicly. Researchers interested in accessing these data may submit a request directly to Palga, in accordance with their procedures (https://www.palga.nl/onder zoek). Proposals requesting access should be directed to Palga, the Dutch Pathology Registry (application number 2023–77), for review and approval.2.4 | OutcomesThe primary outcome of this study is loss to follow-up. For cases with LSIL and treated HSIL, loss to follow-up was defined as having no follow-up or the first surveillance cytology occurring more than 18 and 30 months after the diagnosis, respectively. This corresponds to a 6-month margin beyond the recommended surveillance intervals at 12 and 24 months. Sub-analysis was conducted for each year of inclusion for patients with LSIL to account for the potential impact of the COVID-19 pandemic. The secondary outcome is recurrence of disease during follow-up. Recurrence was defined as a diagnosis of LSIL or HSIL, adenocarci- noma in situ or cervical carcinoma during colposcopy or histology following abnormal surveillance cytology. Recurrence of disease was determined for patients with LSIL who were not lost to follow-up at 18 months and 30 months for patients with treated HSIL.2.5 | Statistical analysisFor baseline characteristics and categorical variables, frequencies and corresponding percentages were calculated for both groups. The chi- square test was used to compare loss to follow-up rates between patients followed up by their general practitioner and those followed up by a gynecologist. The Fisher's exact test was used when the ex- pected count was less than 5 or the observed count was less than 10. A p-value below 0.05 was considered statistically significant. Data were analyzed using SPSS statistics for Windows (version 29, IBM Corp. 2023. Armonk, NY, USA).3 | R E S U LT S 3.1 | Study populationA total of 3786 patients were screened for eligibility. From the 1354 patients with surveillance by the gynecologist, 139 were ex- cluded based on registration and another 322 after reviewing the patient files (Figure 1A). This resulted in 893 eligible patients, of whom 666 were diagnosed with LSIL and 227 with HSIL. In LSIL and HSIL group, an additional 112 and 90 patients were excluded, due to follow-up cytology not being scheduled with a gynecolo- gist or, for HSIL, follow-up indicated 12 months post diagnosis. As a ### Page 4 4 |van de KAM et al.result, 554 patients in the LSIL group and 137 patients in the HSIL group were included. Out of the 2432 patients with follow-up performed by the gen- eral practitioner, 375 were excluded based on registration and 350 after reviewing the patient file (Figure 1B). This resulted in 1707 patients of whom 1220 were diagnosed LSIL and 487 with treated HSIL. Within the LSIL group, 346 patients were excluded due to fol- low-up cytology not being scheduled with a general practitioner. This resulted in 874 patients with LSIL. In the treated HSIL group, 189 pa- tients were excluded. This resulted in 298 patients with treated HSILn = 1354 n = 1215 n = 893 Exclusion based on paënt file n = 322 - Age < 18 years (n = 1) - HIV/AIDS (n = 4) - History of cervical carcinoma (n = 3) - History of LSIL or HSIL (n = 123) - CIN 2 with expectant management (n = 120) - CIN 3 with imiquimod treatment (n = 7) - No HSIL or LSIL at baseline (n = 64) AIS (n = 7) Cervical carcinoma (n = 2) VAIN (n = 4) Vulvar cancer (n = 0) Pap 1 at inclusion (n = 34) Kolposcopy and biopsy not conclusive (n = 17) Exclusion based on registraon n = 139 - No consent (n = 1) - History of LLETZ (n = 135) - No LLETZ or colposcopy at baseline (n = 0) - History of cervical carcinoma (n = 3) LSIL n = 666 HSIL n = 227 LSIL n = 554 HSIL n = 137 Exclusion n = 112 - Follow-up at general praconer (n = 103) Preference of health care professional (n = 56) Preference of paent (n = 47) - No follow-up indicated (n = 1) - < 12 months at general praconer (n = 5) - Passed away during follow up period (n = 3) Exclusion n = 90 - Follow-up at 12 months indicated (n = 54) - Follow-up at 6 months at general praconer by preference of the paent (n = 8) - Follow-up at 24 months at general praconer (n = 23) Preference of health care professional (n = 4) Preference of paent (n = 19) - < 24 months at general praconer (n = 3) - Uterus exrpaon during follow up period (n = 2) n = 2432 n = 2057 n = 1707 Exclusion based on paënt file n = 350 - Age < 18 years (n = 1) - HIV/AIDS (n = 0) - History of cervical carcinoma (n = 4) - History of LSIL or HSIL (n = 115) - CIN 2 with expectant management (n = 174) - CIN 3 with imiquimod treatment (n = 0) - No HSIL or LSIL at baseline (n = 56) AIS (n = 16) Cervical carcinoma (n = 8) VAIN (n = 7) Vulvar cancer (n = 1) Pap 1 at inclusion (n = 14) Kolposcopy and biopsy not conclusive (n = 10) Exclusion based on registraon n = 375 - No consent (n = 124) - History of LLETZ (n = 29) - No LLETZ or colposcopy at baseline (n = 215) - History of cervical carcinoma (n = 7) LSIL n = 1220 HSIL n = 487 Exclusion n = 189 - Follow-up at 12 months indicated (n = 118) - Follow-up at gynaecologist (n = 62) Preference of health care professional (n = 35) Preference of paent (n = 27) - < 24 months at gynaecologist for other problem (n = 5) - Paent moved to other country (n = 3) - Passed away during follow up period (n = 1) Exclusion n = 346 - Follow-up at gynaecologist (n = 312) Preference of health care professional (n = 210) Preference of paent (n = 101) Missing (n = 1) - No follow-up indicated (n = 18) - < 12 months at gynaecologist for other problem (n = 10) - Uterus exrpaon during follow up period (n = 4) - Passed away during follow up period (n = 2) LSIL n = 874 HSIL n = 298(A) (B)F I G U R E 1 Flowcharts of included patients: (A) Gynecologist-based follow-up, (B) general practitioner–based follow-up. ### Page 5 | 5van de KAM et al.who were followed up by the general practitioner. Baseline charac- teristics of the included patients are presented in Table 1.3.2 | Loss to follow-upAmong patients with LSIL, the loss to follow-up rate at 12 months was significantly higher (38.1% (333/874)) for those who were fol- lowed up by their general practitioner compared to those followed up by the gynecologist (16.6% (92/554)). For patients with treated HSIL, the loss to follow-up rate at 24 months was 44.3% (132/298) at the general practitioner, compared to 24.1% (33/137) for surveillance by the gynecologist (Table 2). Sub-analysis per year showed significantly higher loss to follow-up rates across all years for patients with LSIL and follow-up at the general practitioner instead of the gynecologist. For patients who were supposed to return to their gynecologist but independently requested or were advised follow-up care at their general practitioner, loss to follow up at 12 months was significantly higher (30/103 (29.4%)) compared to patients from the general practitioner-based follow-up group who had follow-up at the gyne- cologist (14/312 (4.5%)). For treated HSIL, there was no significant difference between these groups in loss to follow-up at 24 months.TA B L E 1 Baseline characteristics of patients with low- or treated high-grade squamous intraepithelial lesions who received follow-up care from either general practitioners or gynecologists.General practitioner-based follow-up (n = 1172) Gynecologist-based follow-up (n = 691)LSIL (n = 874 (74.6%)) Treated HSIL (n = 298 (25.4%)) LSIL (n = 554 (80.2%)) Treated HSIL (n = 137 (19.8%))Age in years 18–29 142 (16.2) 16 (5.4) 106 (19.1) 10 (7.3) 30–39 408 (46.7) 159 (53.4) 207 (37.4) 74 (54.0) 40–49 191 (21.9) 72 (24.2) 109 (19.7) 35 (25.5) 50–59 113 (12.9) 46 (15.4) 107 (19.3) 12 (8.8)60+ 20 (2.3) 5 (1.7) 25 (4.5) 6 (4.4) HPV status n (%) Positive 841 (96.2) 280 (94.0) 512 (92.4) 123 (89.8) Negative 18 (2.1) 4 (1.3) 17 (3.1) 0 (0.0) Unknown 15 (1.7) 14 (4.7) 25 (4.5) 14 (10.2) Smoking n (%) Yes 228 (26.1) 86 (28.9) 160 (28.9) 50 (36.5) No 583 (66.7) 195 (65.4) 369 (66.6) 82 (59.9)Missing 63 (7.2) 17 (5.7) 25 (4.5) 5 (3.6) Abbreviations: HPV, human papilloma virus; HSIL, high-grade squamous intraepithelial lesion; LSIL, low-grade squamous intraepithelial lesion.TA B L E 2 Number of patients with low-grade and high-grade squamous intraepithelial lesions who were lost to follow-up at the general practitioner and the gynecologist, with sub analysis by year.General practitioner-based follow-up Gynecologist-based follow-up p valueLoss to follow-up LSIL n/N (%)1 333/874 (38.1) 92/554 (16.6) <0.001Loss to follow-up LSIL 2018 n/N (%) 138/324 (42.6) 32/144 (22.2) <0.001Loss to follow-up LSIL 2019 n/N (%) 119/284 (41.9) 32/225 (14.2) <0.001Loss to follow-up LSIL 2020 n/N (%) 76/266 (28.6) 28/185 (15.1) <0.001Loss to follow-up HSIL n/N (%) 132/298 (44.3) 33/137 (24.1) <0.001Gynecologist-based follow-up instead of general practitioner-based General practitioner-based follow-up instead of gynecologist-basedLoss to follow-up LSIL n/N (%) 14/312 (4.5) 30/103 (29.4) <0.001Loss to follow-up HSIL n/N (%) 8/62 (12.9) 4/23 (17.4) 0.7272Note: A p-value below 0.05 was considered statistically significant. Abbreviations: HSIL, high-grade squamous intraepithelial lesions; LSIL, low-grade squamous intraepithelial lesions.1Loss to follow-up was defined as having no follow-up or the first surveillance cytology occurring more than 18 (LSIL) and 30 (HSIL) months after the diagnosis. This corresponds to a 6-month margin beyond the recommended surveillance intervals.2Calculated with Fisher's exact test. ### Page 6 6 |van de KAM et al.3.3 | Recurrence of diseaseIn patients with previous LSIL, recurrence of the lesion during follow-up was observed in 1.5% (8/541) of patients followed up by their general practitioner, as compared with 2.8% (13/462) followed up by the gynecologist. Further progression to HSIL was observed in 6.7% (36/541) in the general practitioner-based follow-up group, compared with 3.7% (17/462) with surveillance by the gynecologist, and adeno- carcinoma in situ occurred in two patients in both groups. One case of cervical carcinoma was reported in the group with gynecologist-based follow-up; no cases in the general practitioner-based follow-up group. In patients with previously treated HSIL, recurrence of an LSIL le- sion was observed in one patient in both groups. Recurrence of the HSIL lesion was observed in 0.6% (1/166) followed up by the general practitioner and 2.9% (3/104) followed up by the gynecologist. No cases of adenocarcinoma in situ or cervical carcinoma were observed.4 | D I S CUS S I O NThe results of this study show that the rate of loss to follow-up for general practitioner-based follow-up after LSIL and treated HSIL is twice as high as that for gynecologist-based surveillance. Subgroup analyses by year show that this difference in loss to follow-up per- sists across all years of inclusion. A low rate of disease recurrence was observed during follow-up. In 2021, only 54.8% of patients invited to participate in the Dutch national cervical screening program accepted the invitation, limiting the overall effectiveness of the program.12,13 A recent study evaluating the impact of loss to follow-up in the Dutch cervical can- cer screening program showed a loss to follow-up rate before refer- ral for colposcopy of 4–8%.14 This emphasizes the overall challenges of patient adherence to cervical screening. Previous studies have consistently reported low follow-up ad- herence rates among patients with abnormal cervical cytology. Srisuttayasathien and Hartz independently observed a similar loss to follow-up rate in women with CIN1, with approximately 30% of patients failing to return for follow-up in a hospital in Thailand and a reproductive health clinic in the United States, respectively.15,16 The COVID-19 pandemic has had a significant impact on cancerscreening services globally.17 In the Netherlands, participation in the national cervical cancer screening program, in which cervical smears are primarily performed by general practitioners, declined during the pandemic.18 Given that routine healthcare services were disrupted by lockdown measures, it was anticipated that the pandemic might have contributed to an increased loss to follow-up.19–21 However, our year-by-year subanalysis found no difference in loss to follow-up among patients requiring follow-up during the COVID-19 pandemic com- pared to those whose follow-up was performed after the pandemic. This suggests that the pandemic may not have played a relevant role in adherence to follow-up care in this context. In many countries, general practitioners play a central role in cer- vical screening programs and follow-up after precancerous lesions.22Previous studies have shown that loss to follow-up is associated with lower socioeconomic status.23–25 However, in our study popu- lation, the average socioeconomic status of the region in which pa- tients received hospital-based follow-up (Eindhoven, the Netherlands) is lower compared to the region in which patients received general practitioner–based follow-up (Breda, the Netherlands).26 Additionally, patient costs are lower in primary care, as follow-up by a general practitioner does not contribute to the mandatory health insurance deductible, unlike hospital-based care. These factors suggest that so- cioeconomic or financial barriers are unlikely to explain the higher loss to follow-up observed in the general practitioner–based group. The relatively high proportion of patients lost to follow-up after surveillance by the general practitioner in this study may be explained by the absence of a structured recall system. Patients who are re- ferred back to their general practitioner are responsible for scheduling their own follow-up appointments, in contrast to gynecologist-based follow-up, where appointments are scheduled automatically. This is supported by evidence from several studies, including experiences from Denmark, where general practitioners have been involved in follow-up of cervical cytology for several years.24,25,27,28 In Denmark, general practitioners receive electronic reminders when appropriate follow-up was not registered. A before-after study evaluating this ap- proach found a reduction in loss to follow-up.27 These findings sug- gest that implementing systematic recall mechanisms at the level of general practice may be an effective strategy to enhance adherence to follow-up care, improving the quality of cervical cancer screening. The clinical relevance of loss to follow-up remains uncertain. Our study shows a low recurrence rate in the group that attended fol- low-up visits. However, we cannot determine whether the group that was lost to follow-up has the same likelihood of recurrence. A study including patients with high-grade CIN treated with LLETZ showed a recurrence of abnormal histology 2 years after treatment of 0.9% of all included patients, which is in line with our findings.29 Additionally, pre- vious research has estimated the median time from high-grade CIN to cervical cancer to be 23.5 years.30 Our study has a relatively short fol- low-up period, making it difficult to determine how many patients who were lost to follow-up have developed or will develop cervical cancer. This study has several strengths and limitations that should be considered when interpreting the findings. This is the first study to evaluate loss to follow-up in patients with LSIL or treated HSIL being referred back to the general practitioner for surveillance. It quantifies the extent of loss to follow-up and explores its clinical impact, providing valuable insights for guideline developers and pol- icymakers. Key strengths of this study include the large population screened for eligibility, resulting in a substantial number of included patients. By leveraging data from two sources, the electronic patient files and the Dutch nationwide pathology database, we enhanced data accuracy through cross-verification, thereby improving the overall reliability of the dataset. Additionally, the data underwent rigorous quality control, ensuring that discrepancies were identified and corrected, thereby strengthening the validity of our results. Despite the strengths of our study, it has several limitations that should be acknowledged. First, possible incomplete registration may ### Page 7 | 7van de KAM et al.have influenced patient selection, potentially leading to missed eligible patients and selection bias. Also, there might be differences in registra- tion between the two centers. To mitigate this risk, we applied an iden- tification strategy that involved ICD-10 codes and registered diagnosis, ensuring that as many eligible patients as possible were included. A dif- ference in exclusions due to lack of consent was observed, which can be attributed to variations in how patients were offered to opt-out at the two centers. Another limitation is the absence of important baseline in- formation, such as ethnicity and educational level. These variables could serve as potential confounders, as they may influence a patient's like- lihood to adhere to follow-up recommendations.31 Finally, as patients with a history of cervical abnormalities were excluded, the generalizabil- ity of the findings is limited to populations without such a history. Our findings may contribute to improvements in (inter)national guidelines for the surveillance of LSIL and treated HSIL. The ob- served loss to follow-up highlights the need for a more structured approach for surveillance following referral back to primary care. Currently, the responsibility for follow-up largely rests with patients, which may contribute to unintended loss to follow-up. Implementing a recall system in primary care will most probably ensure timely and consistent follow-up. The emergence of artificial intelligence (AI) offers additional opportunities to strengthen follow-up strategies. AI-based approaches could support automated recall systems, iden- tify patterns associated with loss to follow-up, and predict patients at higher risk of non-adherence, thereby enabling more targeted in- terventions. In addition, self-sampling for HPV testing may further enhance follow-up in primary care settings. Self-sampling has been shown to improve accessibility and participation, particularly among individuals less likely to attend clinician-based follow-up, and may therefore help reduce loss to follow-up in cervical premalignancy screening and post-treatment surveillance pathways. However, a cur- rent limitation is that self-sampling is restricted to HPV testing and does not allow for cytological assessment, which may limit its appli- cability in follow-up strategies requiring cytology-based evaluation.5 | CO N C LUS I O NSurveillance after a diagnosis of LSIL or treated HSIL by a general practitioner is associated with twice the rate of loss to follow-up compared to gynecologist-based follow-up. The clinical implications of this discrepancy remain uncertain, as disease recurrence in pa- tients who attended follow-up was low. Future research could benefit from adopting a prospective de- sign with a longer follow-up period, allowing for data collection on key patient characteristics and experiences. This approach could facilitate adjustment for confounders and extended data on recur- rence of disease. Qualitative studies using patient interviews or sur- veys would contribute to identifying patient opinions on follow-up at the general practitioner's office and reasons for loss to follow-up. A combination of quantitative and qualitative research could inform the development of tailored strategies to enhance follow-up adher- ence and improve patient-centered care.AU T H O R CO N T R I B U T I O N SLieke van de Kam: investigation, project administration, formal analysis, data curation, writing – original draft, writing – review and editing. Albert Siebers: resources, data curation, writing – review and editing. Ruud Bekkers: conceptualization, writing – review and editing. Dennis van Hamont: funding acquisition, conceptualization, methodology, writing – review and editing, supervision. Jurgen Piek: funding acquisition, conceptualization, methodology, writing – re- view and editing, supervision.F U N D I N G I N FO R M AT I O NThis work was supported by Amphia Science Fund, Breda, The Netherlands [Grant number 2023-1-008]; Incentive Committee Catharina Hospital, Eindhoven, The Netherlands [Grant number 2309 – EFFECTUATE]. The funding sources had no role in the collection, analysis, and interpretation of data; in the writing of the report; and in the decision to submit the paper for publication. The corresponding au- thor had final responsibility for the decision to submit for publication.CO N FL I C T O F I N T E R E S T S TAT E M E N TNo conflicts of interest were declared by any of the authors.DATA AVA I L A B I L I T Y S TAT E M E N TThe data obtained from Palga are subject to strict access regulations. The participant data cannot be shared publicly. Researchers inter- ested in accessing these data may submit a request directly to Palga, in accordance with their procedures (https://www.palga.nl/onderzoek). Proposals requesting access should be directed to Palga, the Dutch Pathology Registry (application number 2023-77), for review and approval.E T H I C S S TAT E M E N TAll procedures performed in this study complied with applicable laws and institutional guidelines and were approved by the Medical Research Ethics Committee United (MEC-U) and relevant institu- tional review boards. The MEC-U determined that this study was not subject to the Dutch Medical Research Involving Human Subjects Act (registration number W23.170; decision date: 16- 08-2023). The requirement for written informed consent was waived due to the large study population and the use of anonymized data. This study was conducted in accordance with the World Medical Association Declaration of Helsinki (2013) and the European General Data Protection Regulation (GDPR). 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Loss to follow-up in patients diagnosed with or treated for low- and high-grade squamous intraepithelial lesions: A comparison of general practitioner-and gynecologist-led surveillance. Acta Obstet Gynecol Scand.2026;00:1-8. doi:10.1111/aogs.70301