The Impact of Being Underweight on the Prognosis of Older Patients With Early Breast Cancer.

Background/aim: The number of older patients with breast cancer has been increasing and a major challenge is to develop optimal treatment strategies for these patients, who often have comorbidities. Obesity is reportedly a poor prognostic factor in breast cancer, however there is limited research on underweight patients. Clarifying the relationship between physique and prognosis may contribute to the establishment of optimal treatment strategies for older patients with breast cancer.

Patients And Methods: This retrospective study examined clinicopathological data from a multicenter collaborative database on 1,076 patients aged 70 years or older who had undergone curative surgery. According to the body mass index (BMI), patient physique was defined as underweight (<18.5 kg/m), normal (18.5-24.9 kg/m) or obese (≥25 kg/m). In this study, we explored the relationship between the physique of patients with breast cancer and outcomes.

Results: Underweight patients had a significantly lower rate of chemotherapy administration (p=0.017) and a higher rate of presence of other cancer (p=0.022). During the observation period (median of 75.2 months), 133 patients (12%) developed recurrent disease and 131 patients (12%) died. Age, BMI, tumor size, progesterone receptor and the presence of other cancer were independent factors relating to overall survival (p<0.001, p=0.027, p=0.002, p=0.008 and p=0.005, respectively). Patients with a low BMI had a significantly shorter overall survival, but there was no association with disease-free survival in this subset of patients.

Conclusion: Overall survival was shorter in underweight older patients with breast cancer. Our data indicate that being underweight should be considered both in treatment decisions and in future studies of outcomes for older patients with breast cancer.