Reducing Chemo Intervals May Positively Impact Outcomes in Advanced Ovarian Cancer

Increasing the number of chemotherapy cycles prior to surgery does not worsen outcomes for patients with advanced epithelial ovarian cancer, if patients achieve complete cytoreduction and receive interval debulking surgery, according to a recent study from the International Journal of Gynecological Cancer.

The authors of the study analyzed how the number of neoadjuvant chemotherapy treatments (chemotherapy drugs that are administered before the surgical removal of a tumor) affected the outcomes for patients with advanced ovarian cancer. Two types of neoadjuvant chemotherapy cycles were used in the study, in which the authors also focused on potential residual disease after surgery. One, interval debulking surgery, was defined as after up to four neoadjuvant chemotherapy cycles, and the other was delayed debulking surgery, meaning it followed at least six cycles of neoadjuvant chemotherapy.

Among the 286 patients who participated in the study, 100 underwent interval debulking surgery and 186 patients underwent delayed debulking surgery. Complete cytoreduction (removal of all sites of cancer from the abdomen) with no residual peritoneal disease (cancer that begins in an organ within the abdomen and spreads to tissue which lines the abdominal wall), or CC0, was achieved for 198 patients, among whom 74 patients were in the group for interval debulking surgery and 124 patients were in the delayed debulking surgery group. Furthermore, the study found that 88 patients had residual disease, in which there were 26 patients from the interval debulking surgery group and 62 patients from the delayed debulking surgery group.

The study also delved into specific findings of residual disease following surgery. Categories of residual disease determined by the study authors included CC0 (no macroscopical residual disease), CC1 (minimal residual disease less than 2.5 millimeters) and CC less than or equal to 1 (all patients with residual disease).

Regarding progression-free survival (PFS, the period during and after treatment of cancer when the disease does not get worse) and overall survival (OS, the period from diagnosis or treatment where patients are still alive), at a median follow-up of 5.2 years both PFS and OS were significantly different for each group. In particular, the CC0 interval debulking and delayed interval debulking groups had 5-year PFS rates of 27% and 18%, respectively. Patients within the group for CC less than or equal to 1 interval debulking and delayed interval debulking had significantly lower 5-year PFS rates, which were 8% and 3%, respectively.

Patients with CC0 had the best outcomes among the groups, according to the authors. The study found that the median PFS was 2.56 years for interval debulking-CC0 and 2.36 years for delayed interval debulking-CC0. The median OS was 4.22 years for interval debulking-CC0 and 5.71 years for delayed interval debulking-CC0. However, patients from the interval debulking-CC1 group had a decreased PFS of 1.94 years and a decreased OS of 2.62 years.

A previous study regarding interval debulking-CC0 and delayed interval debulking-CC0 emphasized that accomplishing cytoreduction without residual disease is important, “regardless of the number of neoadjuvant chemotherapy cycles, with similar progression-free survival (median months 26 vs 37) and overall survival (median months 49 vs 51),” said the authors from the previous study, published in 2020 in the International Journal of Gynecological Cancer.

The authors from the current study further established the previous results from their own study, as they found “similar progression-free survival (median months 30.8 vs 27.5) and overall survival (median months 92.8 vs 58.4) in interval debulking-CC0 versus delayed interval debulking-CC0, respectively.”

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