Myelosuppression by chemotherapy in obese patients with gynecological cancers.

The American Society of Clinical Oncology provides clinical practice guidelines for appropriate cytotoxic chemotherapy dosing for obese adult patients with cancer. The panel recommends that actual body weight should be used when selecting cytotoxic chemotherapy doses regardless of obesity status. However, there have been no reports regarding the appropriate cytotoxic chemotherapy dosing for obese Japanese patients with cancer.

We collected data from 216 gynecological cancer patients who were treated with at least one course of a paclitaxel and carboplatin (TC) regimen or a docetaxel and carboplatin (DC) regimen at Niigata University Medical and Dental Hospital from July 2006 to April 2014. Patients were divided into three groups according to body mass index (BMI): obese (BMI ≥ 25), normal (BMI 18.5-24.9), and underweight (BMI < 18.5), as defined by the Japan Society for the Study of Obesity. We analyzed hematological toxicities by full weight-based chemotherapy in each group.

The rates of grade 3/4 leukocytopenia, neutropenia, and thrombocytopenia were not significantly different among the three BMI groups on all patient analyses. For the TC regimen, the obese and normal groups had significantly lower leukocytopenia (grade 3/4) rates than did the underweight group. Also, significant positive correlations between BMI and the nadirs of leukocytes, neutrophils, platelets, and hemoglobin were observed. For the DC regimen, no significant difference was observed among the BMI groups and the rate of grade 3/4 hematological toxicities.

We did not observe stronger myelosuppression in obese cancer patients compared with non-obese cancer patients. Therefore, the cytotoxic chemotherapy dose should be calculated by the actual body weight and unnecessary dose reduction should be avoided.