Volume-based metabolic tumor response to neoadjuvant chemotherapy is associated with an increased risk of recurrence in breast cancer.

PURPOSE: To evaluate the prognostic value of a volume-based metabolic tumor response to neoadjuvant chemotherapy in patients with locally advanced breast cancer.

MATERIALS AND METHODS: This study was approved by the institutional review board, with waivers of informed consent. One hundred sixty-seven patients (mean age, 44 years; range, 22-68 years) with clinical stage II or III breast cancer who underwent fluorine 18 fluorodeoxyglucose positron emission tomography/computed tomography scans at baseline and after completion of neoadjuvant chemotherapy between July 2006 and June 2013 were selected. The association between the metabolic response parameters and the disease-free survival was assessed by using a Cox proportional hazards regression model and time-dependent receiver operating characteristic curve analysis. Metabolic response parameters included the maximum standardized uptake value (SUVmax), the total metabolic tumor volume (MTVtotal), and the relative decrease in SUVmax and MTVtotal.

RESULTS: In the Cox model, posttreatment SUVmax (P = .029) and MTVtotal (P = .028) and relative decreases in SUVmax (P = .032) and MTVtotal (P = .005) after neoadjuvant chemotherapy were significantly associated with disease-free survival after adjusting for pretreatment clinical stage, yp stage, and tumor subtype. In the time-dependent receiver operating characteristic curve analysis, MTVtotal after neoadjuvant chemotherapy had the highest association with outcome compared with the other parameters (P < .001). MTVtotal of up to 0.2 cm(3) after neoadjuvant chemotherapy was significantly associated with a favorable outcome in patients who did not achieve pathologic complete response after neoadjuvant chemotherapy.

CONCLUSION: The volume-based metabolic tumor response to neoadjuvant chemotherapy is associated with an increased risk of recurrence, regardless of tumor subtype and pathologic tumor response.