Comment on: hyperthermic intraperitoneal chemotherapy as consolidation treatment of advanced stage ovarian cancer.

We read with great interest the study entitled “Hyperthermic intraperitoneal chemotherapy as consolidation treatment of advanced-stage ovarian cancer”- a retrospective chart review by Ko et al. [1]. We appreciate the authors for conducting the trial on this promising futuristic aspect of HIPEC. However, we wish to make certain observations that will further help in comprehending the results of the study.

First, the eligibility criteria of patients for HIPEC needed clarification as the prerequisites for the inclusion of patients remained undefined. Further, we would also like to know the methodology for the selection of the controls. The given study mentioned recruitment of 24 controls retrospectively, but the exact strategy for recruitment was obscured. This aspect of mitigating selection bias among the control population needs due consideration.

The study did mention the significant difference of age in the case and the control group (49.2 years vs. 55.9 years; P=0.03). This limitation of the retrospective comparative studies could be vindicated by applying age-matched cases to control analysis.

The study mentioned that 10 (41.7%) out of 24 patients in the HIPEC group received maintenance platinum-based chemotherapy for positive pathologic results after HIPEC. We are of the opinion that the inclusion of these patients into the final results could have affected the results of disease-free survival (DFS) and overall survival (OS) of HIPEC. Discrete statistical analysis of this subgroup of patients might give us a better comprehension of the results.

We appreciate the authors’ robust work on testing germ-line BRCA mutations in the study population. However, few aspects would require additional clarification. Of the seven patients of the HIPEC group who were positive for BRCA mutation, only three received additional therapy with bevacizumab/olaparib. Similarly, five out of nine patients of the non-HIPEC group who were positive for BRCA mutation received additional chemotherapy. Hence, the criteria for the selection of germline BRCA mutated patients for further treatment with bevacizumab/olaparib remained unexplained. In addition, discrete statistical analyses of DFS and OS in this subgroup of patients with germline BRCA mutation could be thought of as an auxiliary outcome of the study.