Outcomes of minimal residual disease at upfront debulking surgery compared with complete cytoreduction after neoadjuvant chemotherapy

Objective The aim of this study was to compare surgical complexity, post-operative complications, and survival outcomes between patients with minimal residual disease (completeness of cytoreduction (CC) score) CC-1 at the time of primary debulking surgery and those with complete cytoreduction (CC-0) at the time of interval debulking surgery. Methods A retrospective multicenter study was conducted of patients with advanced ovarian cancer (International Federation of Gynecology and Obstetrics stage IIIC–IV) who underwent cytoreductive surgery achieving either minimal or no residual disease between January 2008 and December 2015. Patients underwent either primary or interval debulking surgery after receiving ≥3 cycles of neoadjuvant chemotherapy. The sub-group of patients with primary debulking surgery/CC-1 was compared with those with interval debulking surgery/CC-0. Overall survival and disease-free survival were estimated using the Kaplan–Meier method. Results A total of 549 patients were included, with upfront surgery performed in 175 patients (31.9%) and 374 patients (68.1%) undergoing interval debulking surgery. After primary debulking surgery, 157/175 (89.7%) had complete cytoreduction and 18/175 (10.3%) had minimal residual disease (primary debulking surgery/CC-1 group), while after interval debulking surgery, 324/374 (86.6%) had complete cytoreduction (interval debulking surgery/CC-0 group) and 50/374 (13.4%) had minimal residual disease. The rate of patients with peritoneal cancer index >10 was 14/17 (82.4%) for the primary debulking surgery/CC-1 group and 129/322 (40.1%) for the interval debulking surgery/CC-0 (p<0.001). The rate of patients with an Aletti score of ≥8 was 11/18 (61.1%) and 132/324 (40.7%), respectively (p=0.09) and the rate of major post-operative complications was 5/18 (27.8%) and 64/324 (19.8%), respectively (p=0.38). Overall median disease-free and overall survival were 19.4 months (95% CI 18.0 to 20.6) and 56.7 months (95%CI 50.2 to 65.8), respectively. Median disease-free survival for the primary debulking surgery/CC-1 group was 16.7 months (95% CI 13.6 to 20.0) versus 18.2 months (95% CI 16.4 to 20.0) for the interval debulking surgery/CC-0 group (p=0.56). Median overall survival for the primary debulking surgery/CC-1 group was 44.7 months (95% CI 34.3 to not reached) and 49.4 months (95% CI 46.2 to 57.3) for the interval debulking surgery/CC-0 group (p=0.97). Conclusions Patients with primary debulking surgery with minimal residual disease and those with interval debulking surgery with no residual disease had similar survival outcomes. Interval surgery should be considered when achieving absence of residual disease is challenging at upfront surgery, given the lower tumor burden found during surgery.