Purpose: Weight loss is recommended for overweight or obese patients with breast cancer because obesity is associated with increased risks of breast cancer recurrence and mortality. In this study, relationships among breast cancer treatments, number and frequency of nutritional intervention sessions, and weight loss rates were examined.

Subjects and Methods: A retrospective review of medical records was conducted in obese female patients with breast cancer with body mass index ≥25 kg/m² who underwent nutritional intervention sessions for weight loss between July 2017 and March 2020. Weight changes before and after the intervention were analyzed. The number, frequency, and duration of nutritional intervention sessions and clinicopathological background factors were compared in patients who did and did not achieve a weight loss target of 3%. Factors associated with weight loss of 3% were further analyzed using logistic regression analysis.

Results: Of the 220 patients in the study, 120 (55%) achieved a weight loss target of 3%. All patients had at least 4 nutritional intervention sessions during an intervention period of longer than 5 months. The rate of nutritional intervention sessions was significantly higher in patients who achieved a weight loss target of 3%. In multivariate analysis, at least 4 nutritional intervention sessions was significantly associated with achievement of a weight loss target of 3%.

Conclusion: This study suggests that providing at least 4 nutritional intervention sessions may lead to successful achievement of weight loss of 3% or more.