Reevaluation of negative cervical conizations: Frequency, diagnostic errors, risk factors and management.

OBJECTIVE: Cervical conization is an effective treatment for precancerous lesions. However, in cases where no high-grade lesion is identified in the surgical specimen, managing these patients may be challenging due to the absence of established follow-up protocols for negative conizations. This study aimed to assess the negative conization rates at our institution by histopathological review, identify diagnostic errors, possible risk and recurrence factors and propose follow-up strategies for this group of patients.

METHODS: A retrospective study from January-2010 to December-2020 analyzed patients with negative conization including all surgical techniques and procedure indications. Biopsy and cervical conizations slides were reviewed and patients who kept a negative result underwent deeper levels sectioning of the paraffin blocks with immunohistochemical stains application: p16, Ki-67 and geminin. Data were compared with a control group composed by 29 women with CIN3.

RESULTS: Out of 1022 conizations, 186 were negative (18.1%), with 151 cases selected for the study after excluding 35 patients. Following pathology review, 4 patients were excluded due to false-positive cervical biopsy results, 16 for false-negative conization results and 9 for hidden dysplasia identified after deeper sectioning. The remaining 122 patients were considered truly negative cones (11.9%) and exhibited IHC staining with p16 positive in 20.4% of cases, low Ki-67 expression, and low geminin score in most cases. Specimens with CIN 1 had higher prevalence of p16 staining, Ki-67 expression and geminin score when compared to absence of neoplasia, nevertheless geminin had no statistical difference. Older age, higher parity and IHC pattern with negative p16, low Ki-67 and geminin expressions were identified as risk factors for negative cones (p<0.05). Only 10 patients recurred for high-grade lesions, with no statistically significant risk factors identified.

CONCLUSIONS: The negative conization rate was 11.9%, with diagnostic errors identified across pre-surgical biopsy, cone specimen, and deeper levels. Risk factors included older age, higher parity, low expression of p16, Ki-67 and geminin (p<0.05). Recurrence represented 8.1% of the negative cones, without identification of statistically significant risk factors. Pathological review with deeper level sections and 2-year follow-up are recommended for patients with negative conizations.