Whole-body metabolic tumor volume on F-18 FDG PET/CT as a prognostic factor for breast cancer patients with distant metastasis

Abstract

Objectives This study was performed to evaluate the prognostic relevance of PET parameters [SUVmax in primary tumor (pSUVmax), SUVmax in axillary lymph node (nSUVmax), and whole-body metabolic tumor volume (WBMTV)] measured by F-18 FDG PET/CT in invasive ductal breast cancer patients with distant metastasis at initial diagnosis.

Methods Thirty-two female breast cancer patients with distant metastasis at initial diagnosis who underwent pretreatment F-18 FDG PET/CT were enrolled. Clinicopathological parameters [age, TNM stage, estrogen receptor (ER) status, progesterone receptor (PR) status, human epidermal growth factor receptor2 (HER2) status] and metabolic PET parameters (pSUVmax, nSUVmax, WBMTV) were analyzed for their usefulness in predicting overall survival (OS). Univariate and multivariate analyses were performed to assess their prognostic significances using Kaplan-Meier method and Cox proportional hazards model.

Results Fourteen of 32 patients (43.8 %) expired during follow-up period (mean, 32.6 mo; range, 0.8-61.4 mo). Patients who expired had higher WBMTV than patients who was surviving (571.2±793.7, vs. 69.0±81.8 cm3, P=0.0119). A receiver-operating-characteristic curve demonstrated a WBMTV of 163.8 cm3 (sensitivity, 57.1 %; specificity, 94.4 %; area under the curve, 0.770) to be the optimal cutoff for predicting OS. T stage, N stage, PR status and WBMTV were prognostic factors for predicting OS in univariate analysis. However, age, pSUVmax, nSUVmax, ER status and HER2 status were not significantly associated with OS. According to multivariate analysis, only WBMTV was found to be a single determinant for OS (HR, 5.04; 95 % CI, 1.54-16.6; P=0.0079).

Conclusions The WBMTV on pretreatment F-18 FDG PET/CT could be an independent prognostic factor for OS in invasive ductal breast cancer patients with distant metastasis at initial diagnosis.