Depth of stromal invasion as the most prognostically relevant regression system in locally advanced cervical cancer after neoadjuvant treatment: a systematic review and meta-analysis grading

Background: several different criteria have been proposed to categorize the pathological response in cervical cancer after neoadjuvant therapy; although it is unclear what the most prognostically valuable one is. Objective: to assess the prognostic value of pathological criteria for categorizing the response in cervical cancer after neoadjuvant therapy, through a systematic review and meta-analysis. Methods: four electronic databases were searched from January to December 2020 for all studies, assessing the prognostic value of pathological response in cervical cancer after neoadjuvant therapy. Hazard ratio (HR) for overall survival (OS) was calculated with a significant p-value < 0.05. A meta-analysis was performed for each criteria assessed in at least three studies. Results: sixteen studies were included. Criteria for pathological response included (i) residual stromal invasion < vs. >3 mm; (ii) complete response vs. any residual; (iii) proportion of viable cells; (iv) residual tumor diameter; and (v) intracervical vs. extracervical residual. Criteria (i) and (ii) were suitable for meta-analysis. The presence of a residual tumor with stromal invasion > 3 mm showed a HR of 4.604 (95% CI; 3.229–6.565; p < 0.001), while the presence of any residual showed a HR of 1.610 (95% CI; 1.245–2.081; p < 0.001); statistical heterogeneity was absent in both analyses. Conclusions: dichotomizing the pathological response in cervical cancer after neoadjuvant therapy as < vs. >3 mm stromal invasion is more prognostically valuable than dichotomizing as complete response vs. any residual. Further studies are necessary to evaluate other systems.