Impact of Radiation Therapy Modalities on Loco-regional Control in Inflammatory Breast Cancer.

PURPOSE: In inflammatory breast cancer, radiation therapy intensification is considered a standard of care by some teams, although the level of evidence remains low. We sought to analyze the impact of radiation therapy modalities on the risk of loco-regional and distant relapse. METHODS AND MATERIALS: This retrospective multicenter study included patients with localized inflammatory breast cancer treated between 2010 and 2017. Standard postmastectomy radiation therapy consisted of daily fractions to a total dose of 50 Gy equivalent without a boost or bolus, while intensified radiation therapy referred to the use of a boost or bolus. The cumulative incidence curves of locoregional and distant recurrence were displayed using the competing risk method. RESULTS: Of the 241 included patients, 165 were treated with standard and 76 with intensified radiation therapy. There was significantly more nodal involvement in the intensified group. With a median follow-up of 40 months postradiation therapy, there was no difference between standard versus intensified radiation therapy regarding the cumulative incidence of locoregional (P = .68) or distant recurrence (P = .29). At 5 years, the risks of locoregional and distant recurrence were 12.1% (95% CI, 7.5; 17.7) and 29.4% (95% CI, 21.8; 37.3) for patients treated with standard radiation therapy and 10.4% (95% CI, 4.4; 19.3) and 21.4% (95% CI, 12.6; 31.9) for those treated with intensified radiation therapy. In multivariate analyses, triple-negative subtype and absence of complete pathologic response were associated with a higher risk of loco-regional recurrence. Radiation therapy intensification had no significant impact on locoregional and distant recurrence. For patients with a non-complete pathologic response (n = 172, 71.7%), no significant differences were observed between the 2 groups for loco-regional (P = .80) and distant (P = .39) recurrence. Severe toxicity rates were similar in both groups. CONCLUSIONS: Contrary to other important series, this large retrospective multicentric study did not show a locoregional or distant control benefit of intensified radiation therapy. Pooled prospective studies and meta-analyses of intensified radiation therapy are warranted to endorse this approach.

Preoperative Radiation Therapy for Chemorefractory Localized Inflammatory Breast Cancer.

PURPOSE: Inflammatory breast cancer (IBC) is a rare breast cancer subtype. Chemorefractory nonmetastatic IBC, defined by locoregional progression under neoadjuvant chemotherapy, is a rare situation with few therapeutic options. Owing to the rarity of this clinical presentation and the lack of specific data, no specific management guidelines exist. We evaluated whether preoperative radiation therapy/chemoradiotherapy could achieve locoregional control after first-line neoadjuvant chemotherapy in patients with IBC. METHODS AND MATERIALS: Patients with chemorefractory disease receiving preoperative radiation therapy were identified from a retrospective multicenter cohort of consecutive patients with IBC diagnosed between 2010 and 2017 at 7 oncology centers in France. RESULTS: Overall, 18 patients among the 364 patients (5%) treated for IBC had progressive disease during neoadjuvant chemotherapy. These patients had aggressive tumors with lymph node involvement at diagnosis (n = 17; 94.4%), triple-negative subtype (n = 11; 61.1%), Scarff Bloom and Richardson grade 3 (n = 10; 55.6%), and high Ki67 (median, 56.0%). After preoperative radiation therapy, all patients had a complete (n = 1; 5.6%) or partial (n = 17; 94.4%) locoregional response. One patient (5.6%) experienced acute grade 3 dermatitis. Twelve (66.7%) patients underwent surgery as planned. The estimated median follow-up was 31 months. The median overall survival, disease-free survival, distant metastases-free survival, and locoregional recurrence-free survival were 19 months, 4.5 months, 5 months, and 6 months, respectively. Ultimate locoregional control was obtained for 11 patients (61.1%), and 13 patients (72.2%) experienced metastatic progression. Triple-negative subtype (hazard ratio [HR], 15.54; P = .011) and surgery (HR, 0.23; P = .030) were significantly associated with overall survival in the univariate analysis. In multivariate analyses, the triple-negative subtype remained a significant prognostic factor (HR, 13.04; P = .021) for overall survival. CONCLUSIONS: Preoperative radiation therapy is a feasible approach with acceptable toxicities. It allowed surgery and ultimate locoregional control in a majority of patients. The lack of translation into better survival has been a challenge, in part owing to the metastatic propensity of patients with chemorefractory IBC, especially in the overrepresented triple-negative population in this series.

Different Prognostic Values of Tumour and Nodal Response to Neoadjuvant Chemotherapy Depending on Subtypes of Inflammatory Breast Cancer, a 317 Patient-Study.

Inflammatory breast cancer (IBC) is a rare entity with a poor prognosis. We analysed the survival outcomes of patients with nonmetastatic IBC and the prognostic value of tumour or nodal responses to assess their individual prognostic impact across IBC subtypes. This retrospective multicentre study included patients diagnosed with IBC between 2010 and 2017 to account for advances in neoadjuvant systemic therapies and modern radiotherapy at seven oncology centres in France. Three hundred and seventeen patients were included and analysed. After a median follow-up of 52 months, the 5-year DFS was lower for triple-negative (TN) (50.1% vs. 63.6%; p < 0.0001). After multivariate analyses, incomplete nodal response was the only significant prognostic factor in the triple-negative group (HR:6.06). The poor prognosis of TN-IBC was reversed in the case of nodal response after neoadjuvant chemotherapy. Breast response does not appear to be a decisive prognostic factor in patients with TN-IBC compared to lymph node response. Despite improvements in neoadjuvant treatments, IBC remains associated with a poor prognosis. In TN-IBC patients, lack of pathological complete node response was associated with poorer survival than any other group. Treatment intensification strategies are worth investigating.