Whole-Body Metabolic Tumor Volume, as Determined by (18)F-FDG PET/CT, as a Prognostic Factor of Outcome for Patients With Breast Cancer Who Have Distant Metastasis

Objective: This study was performed to evaluate the prognostic relevance of PET parameters measured by (18)F-FDG PET/CT in patients with invasive ductal carcinoma of the breast (IDC) who had distant metastasis at the time of initial diagnosis.

Materials and methods: Forty women with IDC who had distant metastasis at the time of initial diagnosis and who underwent FDG PET/CT before receiving treatment were enrolled in the study. Clinicopathologic parameters and metabolic PET parameters, including the maximum standardized uptake value (SUVmax) of the primary tumor (pSUVmax), the SUVmax of the axillary lymph node (nSUVmax), the highest SUVmax of whole malignant lesions (wSUVmax), the whole-body (WB) metabolic tumor volume (MTV), and WB total lesion glycolysis (TLG), were analyzed to determine their usefulness in predicting overall survival (OS). Univariate and multivariate analyses were performed with the use of Kaplan-Meier and Cox proportional hazards models.

Results: Twenty-one of the 40 patients (52.5%) died during follow-up (mean follow-up, 36.4 months; range, 0.8-71.4 months). Nonsurvivors had a statistically significantly higher mean (± SD) WB MTV than did survivors (424.0 ± 683.9 vs 92.1 ± 96.3 cm(3); p = 0.0430). T category, performance of palliative surgery, presence of visceral metastasis, wSUVmax, WB MTV, and WB TLG were identified by univariate analysis as prognostic factors for OS, whereas age, N category, hormone receptor status, status, triple-negative breast cancer status (defined as a tumor for which estrogen receptor, progesterone receptor, and ERBB2 statuses were all negative), pSUVmax, and nSUVmax were not. Multivariate analysis revealed that only WB MTV independently predicted OS (hazard ratio, 4.10; 95% CI, 1.17-14.31; p = 0.0280).

Conclusion: The WB MTV value, as determined by FDG PET/CT performed before treatment, was found to be an independent prognostic factor for OS in patients with IDC who had distant metastasis at the time of initial diagnosis.