Impact of positive surgical margin location on biochemical recurrence in pT3 prostate cancer after robot-assisted radical prostatectomy: a retrospective cohort study

Abstract

Background: A positive surgical margin (PSM) following radical prostatectomy is a significant prognostic factor that increases the risk of biochemical recurrence (BCR). However, the clinical relevance of the relationship between PSM localization, its extent, and the histopathological characteristics of the tumor and BCR remains unclear. This study aimed to evaluate the association between PSM features, tumor grade, and BCR. Methods: Patients with pathological stage pT3 who had not received adjuvant therapy were included in the study. Surgical margin status was classified according to localization, length, and the presence of an accompanying tertiary pattern. Patients were compared in terms of clinical and pathological characteristics. The development of BCR was analyzed in relation to PSA dynamics and histopathological parameters. Results: The presence of PSM significantly increased BCR rates and demonstrated a strong association with tertiary pattern positivity. The tertiary pattern was observed nearly three times more frequently, particularly in patients with PSM. Cases with PSM length > 1 mm exhibited substantially higher BCR, and this parameter emerged as the strongest independent predictor of BCR. Although localization was not generally significant, apical involvement was identified as the only anatomical site associated with BCR. Differences in ISUP distributions according to PSM localization were considered notable in terms of regional tumor biology. Conclusions: PSM localization alone is not a determinant of BCR; however, PSM length, the presence of a tertiary pattern, and apical involvement provide clinically meaningful prognostic information. Therefore, detailed reporting of margin characteristics in pathology reports is critically important for accurately guiding postoperative treatment strategies