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Complete cytoreduction for ovarian cancer: Is it enough for long‐term survival?

Dear Editor, The use of combined treatment based on hyperthermic intraperitoneal chemotherapy (HIPEC) for patients with ovarian cancer has been attracting more and more attention from clinicians over the past 2 decades. The efficacy of cytoreductive surgery (CRS) and HIPEC in the combined treatment of patients with ovarian cancer is currently actively being investigated in 2 dozen prospective randomized trials in different parts of the world. The results of the first randomized study of CRS/ HIPEC efficacy in recurrent ovarian cancer were published by Spiliotis et al. They showed a probable increase in patients’ survival rate in the experimental group as opposed to the CRS+ systemic chemotherapy group. The results of the first randomized study of CRS/HIPEC efficacy in primary ovarian cancer were published in The New England Journal of Medicine in early 2018 by van Driel et al. Survival curves showed a probable increase in the prognosis of patients. However, when an 87% level of complete cytoreductions (CC‐0,1) was achieved, the median disease‐free survival rate in a group under research was only 14.2 months, and a 3‐year disease‐free survival rate was only 17%. In a study conducted by Deraco et al it was found that when a macroscopic complete cytoreduction (CC‐0) in 84% of patients with recurrent ovarian cancer was achieved, the median disease‐free survival rate was only 10.8 months. A number of other retrospective studies showed that high levels of complete cytoreduction result in intraperitoneal recurrence in most patients. It is evident then that the use of the peritoneal cancer index as a prognostic criterion in CRS/HIPEC practice should not be the sole consideration because it does not allow achieving a long‐term survival in a potentially favorable group of patients with complete cytoreduction of implants from the abdomen, but also necessitates consideration of tumor process morphology. An integral factor of peritoneal carcinomatosis that considers the degree of intraperitoneal tumor spread (peritoneal cancer index), clinical symptoms, as well as hte morphology of the tumor has been proposed for colorectal cancer—peritoneal surface disease severity score (PSDSS). Only 1 study has examined the use of the PSDSS in a population of ovarian cancer patients with peritoneal carcinomatosis. In this multi‐ institutional study, the prognostic value of the PSDSS was evaluated retrospectively in 553 patients with epithelial ovarian cancer who received CRS/HIPEC, and a statistically significant difference in the median survival rate was observed. However, the article does not present a clear algorithm for stratification of patients into the PSDSS stages based upon the score assessment for the 3 categories. In our study, we conducted an extrapolation of PSDSS for ovarian cancer based on the classification of patients according to 2 pathogenetic types of ovarian cancer. Such stratification of ovarian cancer enables to objectively grade it in the section of “morphological structure of the tumor.” This approach allowed for distinguishing the category of patients with the highest levels of survival. Consequently, ovarian cancer patients with PSDSS Stage I and Stage II fall into a category of patients in which the use of an aggressive combined treatment with CRS/HIPEC has the highest chances to implement its effectiveness. The reported results using PSDSS for recurrent ovarian cancer patients who were treated with CRS/HIPEC according to Iavazzo et al are quite optimistic. At acceptable levels of postoperative morbidity and mortality, the median overall survival was registered at the 48‐month level. The use of PSDSS in the study of recurrent ovarian cancer resulted in a probable difference in survival in both disease‐free and overall median survival. The median overall survival was 70 ± 20 months (in Stage I), 34 ± 12.8 months (Stage II), 19 ± 7.2 months (Stage III), and 11 ± 4.2 months (Stage IV). Positive results noted in the first reports on extrapolation of PSDSS for the ovarian cancer study show the necessity for further research in this direction as well as the use of this prognostic criterion as an effective tool for the selection of patients for prospective randomized trials. In conclusion, we would like to express our gratitude to the editorial board as well as to colleagues from Greece for their interest in this clinical problem. Only in the context of a collaborative and continuous scientific discussion, we will be able to understand and clarify the promising role of the PSDSS score in ovarian cancer patients to identify the best use of combined treatment.