ObjectiveHigh-grade serous ovarian cancer accounts for a disproportionate number of deaths from gynecologic malignancies. It typically presents at an advanced stage and with a high volume of ascites a common presenting feature. The aims of this study is to evaluate the association between ascites volume at the time of primary surgery for advanced stage ovarian cancer with surgical outcomes and patterns of recurrence.MethodsA retrospective review of stage III/IV high-grade serous ovarian cancer patients who underwent primary surgery at two centers between March 2003 to June 2016. Patients were categorized as low-volume ascites (≤ 200 mL) vs high-volume (≥ 1 L). Patients with an unknown volume of ascites or neoadjuvant chemotherapy were excluded. Patients' characteristics were compared for the two groups. Probability of recurrence over time and the HR from a proportional hazards model for sub-distribution were calculated.ResultsA total of 210 patients were included, 90 (42.9%) patients in the low-volume and 120 (57.1%) patients in the high-volume group. Patients in the low-volume group were older with a median age of 60.2 years vs 56.8 years in the high-volume group and had lower serum CA-125 levels (mean 223 vs 971.5 U/mL). The low-volume group had better surgical outcome with suboptimal debulking (> 1 cm residual disease) in only 17.8 % vs 39.2 % in the high-volume group and had longer median time to recurrence (2.8 years in low-volume vs 1.6 years high-volume group). At the time of recurrence, the low-volume group had a less disseminated pattern of recurrence, lower rates of ascites (20 % in the low-volume group vs 37.2 % in the high-volume group), and a trend toward lower serum CA125 levels (mean 352.8 vs 596.9 U/mL).ConclusionsAdvanced stage serous ovarian cancer patients who present with low-volume ascites have lower serum CA125 levels, more optimal cytoreduction rates, and longer disease-free interval. The low-volume group had less ascites, less disseminated disease, and a trend toward lower serum CA125 levels at the time of recurrence.