Obesity affects health in several ways, but new research shows obesity can have minimal impact on ovarian cancer survival. A study by researchers at the University of Alabama at Birmingham (UAB) Comprehensive Cancer Center found ovarian cancer survival rates are the same for obese and non-obese women if their chemotherapy doses are closely matched to individual weight.

The findings contradict earlier research that shows obese women have lower ovarian cancer survival rates compared to non-obese patients. In the UAB study, such survival disparity disappeared when chemo doses were calculated by actual body weight rather than a different dosing standard, said Kellie Matthews, M.D., a UAB gynecologic oncologist and lead author on the new study.

“Often chemotherapy dosing is calculated using ‘ideal’ body weight as a guide. We found using actual body weight works best, and it wipes away much of the difference in survival rates between obese and non-obese patients,” Matthews said.

The results are published online in the journal Gynecologic Oncology.

Researchers reviewed the medical records of 304 patients diagnosed with an aggressive form of the disease called epithelial ovarian cancer. Patients were of similar cancer stage and grade, and all had surgery followed by chemo.

The analysis showed that when actual body weight was used in chemo dosing the overall survival is 40 months for non-obese patients and 47 months for obese patients, not a significant difference, Matthews said. Similar outcomes are seen in obese and non-obese cancer survivors being monitored for recurrence of their ovarian cancer.

UAB’s chemo dosing formula includes actual weight, body mass index (BMI) and other factors, Mathews said. Obesity is defined as a BMI (BMI: kg/m²) of 30 or more.

The study authors acknowledged that while it was possible to follow this formula and remove obesity as a negative indicator for ovarian cancer survival, obesity still puts women at increased risk for complications related to cancer surgery, such as greater blood loss and stubborn-to-heal incisions. Also, research shows obese women are more likely to have other health problems such as diabetes and cardiovascular disease that may impact cancer treatment.

The Gynecologic Oncology study was collaboration between UAB’s Division of Gynecologic Oncology, the Division of Hematology/Oncology and the University of South Alabama’s Mitchell Cancer Institute in Mobile.