The prognostic value of residual disease after neoadjuvant chemotherapy in advanced ovarian cancer; A systematic review.

INTRODUCTION: The ability to minimize residual disease during primary cytoreductive surgery is the strongest predictor for improved overall survival in advanced ovarian cancer. But while the probability to achieve a macroscopic complete resection increases if surgery is preceded by neoadjuvant chemotherapy (NACT), survival rates after NACT are similar to those observed after primary surgery. This may suggest that the prognostic effect of residual disease is altered after NACT. More specifically, randomized data suggest that there is no difference between optimal (0.1-1 cm) and suboptimal (>1 cm) cytoreductive surgery after NACT. Therefore, the aim of the current review is to establish the prognostic effect of the amount of residual disease after interval cytoreductive surgery (ICS) on overall survival.

METHODS: Potential articles for inclusion in the current review were systematically searched through Medline, Embase and Cochrane in September 2017. Median overall survival (mOS) was summarized by the outcome of ICS per study. In addition, mOS was summarized for all studies together stratified by the outcome of ICS, based on the principle of a weighted average.

RESULTS: In total, 3677 unique manuscripts were individually screened on title and abstract, which resulted in 11 individual studies that comprised a total of 2178 patients. MOS was 41 months for patients with no residual disease (range 33-54 months), 27 months for patients with 0.1-1 cm of residual disease (range 19-38 months) and 21 months with >1 cm of residual disease (range 14-27 months). Six studies showed significant differences between optimal and suboptimal ICS, while five studies showed no differences.

CONCLUSION: The summary of the currently available literature showed that after NACT, patients with optimal cytoreductive surgery experience lengthened survival compared to patients with suboptimal cytoreductive surgery. Patients with no macroscopic residual disease have, however, the most favorable survival outcomes, similar to what is seen after primary cytoreductive surgery.