Objective Determining the risk factors associated with parametrial involvement (PMI) is of paramount importance to decrease the multimodality treatment in early-stage cervical cancer. We investigated the preoperatively assessable clinical and pathological risk factors associated with PMI in surgically treated stage IB1–IIA2 cervical cancer.

Methods A retrospective cohort study of women underwent Querleu-Morrow type C hysterectomy for cervical cancer stage IB1–IIA2 from 2001 to 2015. All patients underwent clinical staging examination under anesthesia by the same gynecological oncologists during the study period. Evaluated variables were age, menopausal status, body mass index, smoking status, FIGO (International Federation of Obstetrics and Gynecology) stage, clinically measured maximal tumor diameter, clinical presentation (exophytic or endophytic tumor), histological type, tumor grade, lymphovascular space invasion, clinical and pathological vaginal invasion, and uterine body involvement. Endophytic clinical presentation was defined for ulcerative tumors and barrel-shaped morphology. Two-dimensional transvaginal ultrasonography was used to measure tumor dimensions.

Results Of 127 eligible women, 37 (29.1%) had PMI. On univariate analysis, endophytic clinical presentation (P = 0.01), larger tumor size (P < 0.001), lymphovascular space invasion (P < 0.001), pathological vaginal invasion (P = 0.001), and uterine body involvement (P < 0.001) were significantly different among the groups with and without PMI. In multivariate analysis endophytic clinical presentation (odds ratio, 11.34; 95% confidence interval, 1.34–95.85; P = 0.02) and larger tumor size (odds ratio, 32.31; 95% confidence interval, 2.46–423.83; P = 0.008) were the independent risk factors for PMI. Threshold of 31 mm in tumor size predicted PMI with 71% sensitivity and 75% specificity. We identified 18 patients with tumor size of more than 30 mm and endophytic presentation; 14 (77.7%) of these had PMI.

Conclusions Endophytic clinical presentation and larger clinical tumor size (>3 cm) are independent risk factors for PMI in stage IB–IIA cervical cancer. Approximately 78% of the patients with a tumor size of more than 3 cm and endophytic presentation will require adjuvant chemoradiation for PMI following radical surgery. Considering clinical tumor presentation along with tumor size can enhance the physician’s prediction of PMI in early-stage cervical cancer.