Objective The association between muscle mass and strength decrease by aging (Sarcopenia) and adverse events of chemotherapy and prognosis has been reported in several solid cancers. Skeletal muscle mass has also been shown to be a prognostic factor in elderly epithelial ovarian cancer, it has been unclear in the Japanese population. Furthermore, the association between more easily calculated iliopsoas muscle mass and prognosis of elderly epithelial ovarian cancer patients has not been clarified. This study aimed to evaluate association between iliopsoas muscle mass and prognosis of elderly ovarian cancer patients in the Japanese population.

Method Medical charts of 110 epithelial ovarian cancers aged 60 years and older at our hospitals between 2013 and 2014 were retrospectively reviewed. Muscle areas of bilateral psoas major muscles at the third lumbar vertebra were measured using images obtained by computed tomography tested before treatment. Psoas muscle index (PMI) was calculated as the psoas muscle area divided by the height squared. Cox-regression Hazard Models were applied.

Results Median follow-up period was 40 months, average age was 67.8 years, and median PMI was 313 mm2/m2 (range 137–572). 44 patients (40.0%) with less than 300 mm2/m2 PMI were found to be statistically significant poor prognosis in multivariate analysis (Hazard Ratio: 2.896, 95% Confidence Interval: 1.1510–7.287, P value: 0.024).

Conclusions Low PMI was a statistically significant poor prognostic factor in Japanese elderly patients with epithelial ovarian cancer. It suggests that low PMI can be a biomarker that predicts poor prognosis in elderly patients with epithelial ovarian cancer.