This study prospectively evaluated the yield of fluorodeoxyglucose positron emission tomography/computed tomography ( ¹⁸ FDG-PET-CT) in patients with clinical stages II and III breast cancer and the impact of PET-CT results on prognosis. In the course of 71 months, 254 consecutive patients with clinical stages II and III breast cancer (based on clinical examination, mammography, breast magnetic resonance imaging, and locoregional ultrasonography) underwent ¹⁸ FDG-PET-CT. The yield was assessed in the whole population and for each American Joint Committee on Cancer subgroup. The prognostic impact of PET-CT findings was analyzed. Tests of statistical significance were two-sided. ¹⁸ FDG-PET-CT changed the clinical stage in 77 of 254 patients (30.3%; 95% confidence interval [CI] = 25.0% to 36.2%). It showed unsuspected N3 disease (infraclavicular, supraclavicular, or internal mammary nodes) in 40 patients and distant metastases in 53. PET-CT revealed distant metastases in 2.3% (1 of 44) of clinical stage IIA, 10.7% (6 of 56) of stage IIB, 17.5% (11 of 63) of stage IIIA, 36.5% (27 of 74) of stage IIIB, and 47.1% (8 of 17) of stage IIIC patients. Among 189 patients with clinical stage IIB or higher disease and adequate follow-up, disease-specific survival was statistically significantly shorter in the 47 patients scored M1 on ¹⁸ FDG-PET-CT in comparison with those scored M0, with a three-year disease-specific survival of 57% vs 88% ( P < .001). In multivariable analysis, only distant disease on PET-CT and triple-negative phenotype were statistically significant prognostic factors. The relative risk of death was 26.60 (95% CI = 6.60 to 102.62) for M1 vs M0 patients. The yield of ¹⁸ FDG-PET-CT appeared substantial in patients with clinical stage IIB or higher breast cancer. In these patients, ¹⁸ FDG-PET-CT provided powerful prognostic stratification.

Introduction: Molecular apocrine (MA) tumors are estrogen receptor (ER) negative breast cancers characterized by androgen receptor (AR) expression. We analyzed a group of 58 transcriptionally defined MA tumors and proposed a new tool to identify these tumors. Methods: We performed quantitative reverse transcription PCR (qRT-PCR) for ESR1, AR, FOXA1 and AR-related genes, and immunohistochemistry (IHC) for ER, PR, Human Epidermal Growth Factor Receptor 2 (HER2), CK5/6, CK17, EGFR, Ki67, AR, FOXA1 and GCDFP15 and we analyzed clinical features. Results: MA tumors were all characterized by ESR1(-) AR(+) FOXA1(+) and AR-related genes positive mRNA profile. IHC staining on these tumors showed 93% ER(-), only 58% AR(+) and 90% FOXA1(+). 67% and 57% MA tumors were HER2(3+) and GCDFP15(+), respectively. Almost all MA tumors (94%) had the IHC signature HER2(3+) or GCDFP15(+) but none of the 13 control basal-like (BL) tumors did. Clinically, MA tumors were rather aggressive, with poor prognostic factors. Conclusion: MA tumors could be better defined by their qRT-PCR-AR profile than by AR IHC. In addition, we found that HER2 or GCDFP15 protein overexpression is a sensitive and specific tool to differentiate MA from BL in the context of ER negative tumors. A composite molecular and IHC signature could, therefore, help to identify MA tumors in daily practice.

Triple-negative breast cancer, an aggressive subtype, represents 15% of invasive breast tumors. This prospective study investigated whether early changes in ¹⁸F-FDG tumor uptake during neoadjuvant chemotherapy (NAC) can predict outcomes. Methods: Twenty (M0) patients underwent ¹⁸F-FDG PET/CT at baseline and after the second cycle. NAC was continued irrespective of PET results. Results: At surgery, 6 patients had a pathologic complete response, whereas 14 had residual tumor. Four patients showed early relapse (in the 2 y after surgery). There were 11 metabolic responders and 9 nonresponders using a 42% decrease in maximum standardized uptake value as a cutoff. In nonresponding patients, the risk of residual tumor at surgery was 100% (vs. 45% in responders; P = 0.014), and the risk of early relapse was 44% (vs. 0%; P = 0.024). Conclusion: A less than 42% decrease in ¹⁸F-FDG uptake at 2 cycles means residual tumor at the end of NAC and a high risk of early relapse.

The purpose of this study was to prospectively evaluate the role of ¹⁸F-FDG PET/CT in patients with stage IIA, IIB, or IIIA breast cancer. Methods: During 56 mo, 131 consecutive patients with large (>2 cm) breast cancer and clinical stage IIA, IIB, or IIIA (based on clinical examination, mammography, breast MRI, and ultrasonography) underwent ¹⁸F-FDG PET/CT. The nuclear physician was unaware of the results of any other procedure (bone scan, chest radiography, liver ultrasound, or thoracoabdominal CT scan). Results: Of the 131 examined patients, 36 had clinical stage IIA (34 T2N0 and 2 T1N1), 48 stage IIB (20 T3N0 and 28 T2N1), and 47 stage IIIA (29 T3N1, 9 T2N2, and 9 T3N2). ¹⁸F-FDG PET/CT modified staging for 5.6% of stage IIA patients, for 14.6% of stage IIB patients, and for 27.6% of stage IIIA patients. However, within stage IIIA, the yield was specifically high among the 18 patients with N2 disease (56% stage modification). When considering stage IIB and primary operable IIIA (T3N1) together, the yield of ¹⁸F-FDG PET/CT was 13% (10/77); extraaxillary regional lymph nodes were detected in 5 and distant metastases in 7 patients. In this series, ¹⁸F-FDG PET/CT outperformed bone scanning, with only 1 misclassification versus 8 for bone scanning (P = 0.036). Conclusion: ¹⁸F-FDG PET/CT provided useful information in 13% of patients with clinical T3N0, T2N1, or T3N1 disease. The yield was more modest in patients with stage IIA. The high yield in the case of N2 disease demonstrates that stage IIIA comprises 2 quite distinct groups of patients.