Conclusion
High SUVmax on preoperative PET showed association with elevated risk of locoregional recurrence and any recurrence. Pre-treatment PET may improve assessments of recurrence risk and clarify indications for post-mastectomy radiotherapy in this subset of patients.
Methods
Of 712 consecutive patients with T1-T2/N1 breast cancer treated during 2003-2012, 109 had undergone preoperative (18)F-fluorodeoxyglucose/PET and were included. Metabolic (maximum standardized uptake value [SUVmax]), volumetric (metabolic tumor volume [MTV]), and combined (total lesion glycolysis [TLG]) indices were measured. The resulting values were analyzed and compared with clinical outcome.
Purpose
The purpose of this study is to assess the utility of positron emission tomography (PET) for predicting recurrence among patients with T1-T2/N1 breast cancer who were treated with mastectomy. Materials and
Results
At the median follow-up of 46.7 months, the 3-year relapse-free survival (RFS) rate was 95.2%. SUVmax (area under curve, 0.824) was more useful than MTV or TLG as a means of identifying patients at high risk for any recurrence. In multivariate analysis, SUVmax remained an independent risk factor for RFS (p=0.006). Using the method of Contal and O'Quigley, a SUVmax threshold of 5.36 showed the best predictive performance. The PET-based high-risk group (≥ 5.36 in either breast or nodes) had more T1c-T2, high-grade, hormone-receptor negative, and invasive ductal carcinoma tumors than the low-risk group (< 5.36 in both breast and nodes). The prognosis was much worse when high SUVmax (≥ 5.36) was detected in nodes (p < 0.001). In the no-radiotherapy cohort, the PET-based high-risk group had increased risk of locoregional recurrence when compared to the low-risk group (p=0.037).