The treatment of HER2-positive (HER2+) and triple negative (TN) breast cancer (BC) increasingly includes systemic therapies that can be associated with a risk of drug-induced pneumonitis and may overlap with the delivery of radiotherapy, which carries an independent risk of pneumonitis. The aim of this study is to characterize the interaction between trastuzumab-emtansine (T-DM1), pembrolizumab and radiotherapy in modulating the risk of pneumonitis in a real-world setting. A retrospective, single institution, chart review identified patients with non-metastatic HER2+ or TN BC, who were treated with adjuvant radiotherapy between 2019 and 2024. Among this cohort the proportion with pneumonitis diagnosed within 1-year following completion of radiotherapy was evaluated. The association of grade ≥2 pneumonitis (G2P+) with clinical factors of interest was examined using univariate and multivariable logistic regression. Of 863 eligible patients, 528 were HER2+ and 335 were TN. Overall the rate of G2P+ was 2.8 %; 3.6 % for HER2+ and 1.5 % for TN patients. On univariate analysis, radiation treatment volume, clinical stage, and receipt of T-DM1 were associated with G2P+, however, only T-DM1 (OR = 4.16, 95 % CI = 1.59-10.92, p < 0.01) and clinical stage III vs. II (OR 2.69, 95 % CI 1.03-7.02, p = 0.04) remained significant on multivariable analysis. Overall, the probability of G2P+ in patients receiving radiotherapy for HER2+ or TN BC is low. However, concurrent T-DM1 and radiotherapy was associated with significantly higher rates of pneumonitis than previously reported, suggesting a cautionary approach when combining the two therapies.

(1) Background: To make recommendations on the most effective therapy options for Ductal Carcinoma of the Breast (DCIS) patients; (2) Methods: MEDLINE, EMBASE, Cochrane Library, PROSPERO databases, and main relevant guideline websites were searched. Draft versions of the guideline went through formal internal and external reviews, with a final approval by the Program in Evidence Based Care and the DCIS Expert Panel. The Grading of Recommendations, Assessment, Development, and Evaluation approach was followed; (3) Results: Based on the current evidence from the systematic review and this guideline authors’ clinical opinions, initial draft recommendations were developed to improve the management of patients with DCIS. After a comprehensive internal and external review process, ten recommendations and 27 qualifying statements were eventually made. This guideline includes recommendations for the primary treatment of DCIS with surgical treatment and/or radiation therapy and the management of DCIS after primary treatment for patients with DCIS, including DCIS with microinvasion (<1 mm through the duct); (4) Conclusions: The current guideline was created after a systematic review and a comprehensive internal and external review process. We believe this guideline provides valuable insights that will be useful in clinical decision making for health providers.

Prompted by COVID-19 and publication of the FAST-Forward study, our institution rapidly implemented ultrahypofractionated radiation therapy (U-HFRT) for patients with early-stage breast cancer. Our objective was to evaluate our early experience and toxicity outcomes for U-HFRT. Patients with consecutive stage 0-II breast cancer treated with adjuvant whole breast radiation therapy (RT) were evaluated. Patient demographics and treatment characteristics were extracted and categorized into 2 cohorts: U-HFRT, 26 Gy/5 fractions (F) and M (moderate)-HFRT, 40.05 Gy/15F. Physician-assessed skin toxicity was evaluated using the Radiation Therapy Oncology Group radiation morbidity scale at baseline/during RT, 1 to 90 days post-RT and >90 days post-RT. Descriptive statistics summarized patient demographics and treatment characteristics and were stratified based on dose fractionation. A multivariable logistic model evaluated associations between toxicity and fractionation. Between May 2020 and March 2021, 320 patients were evaluated: 133 (41.6%) received U-HFRT and 187 (58.4%) received M-HFRT. For the U-HFRT cohort, median age at diagnosis was 65.4 years (range, 57-73), 71% had hormone receptor-positive invasive disease, and 18% had ductal carcinoma in-situ. All patients received whole breast RT, and 33% received a boost. U-HFRT was used more in patients who were older, hormone receptor-positive, and did not receive a boost (P < .001). On multivariable analysis, M-HFRT patients experienced significantly more grade 1+skin toxicity during RT (odds ratio = 32.3, P < .001), while 1 to 90 days post-RT, M-HFRT patients experienced less grade 1+ toxicity (odds ratio = 0.36, P < .014) after adjusting for boost, age, and chemotherapy. Rates of skin toxicity >90 days post-RT were low overall. This study reports real-world clinical outcomes of patients with stage 0-II breast cancer treated with U-HFRT. We observed low rates of acute skin toxicity compared to M-HFRT, confirming its acceptability as a standard regimen for select patients. Longer term follow-up would be necessary to confirm clinical outcomes in terms of both local control and late normal tissue toxicity.

On 15–16 June 2023, healthcare professionals and breast cancer patients and advocates from across Canada met in Toronto, Ontario, for the 2023 Canadian Breast Cancer Symposium (CBSC.). The CBSC. is a national, multidisciplinary event that occurs every 2 years with the goal of developing a personalized approach to the management of breast cancer in Canada. Experts provided state-of-the-art information to help optimally manage breast cancer patients, including etiology, prevention, diagnosis, experimental biology, and therapy of breast cancer and premalignant breast disease. The symposium also had the objectives of increasing communication and collaboration among breast cancer healthcare providers nationwide and providing a comprehensive and real-life review of the many facets of breast cancer. The sessions covered the patient voice, the top breast cancer papers from different disciplines in 2022, artificial intelligence in breast cancer, systemic therapy updates, the management of central nervous system metastases, multidisciplinary management of ductal carcinoma in situ, special populations, optimization-based individual prognostic factors, toxicity management of novel therapeutics, survivorship, and updates in surgical oncology. The key takeaways of these sessions have been summarized in this conference report.

Background: The BREAST-Q is a widely validated patient-reported outcome measure following breast surgery and adjuvant therapies. Although several language adaptations exist, the Breast Conserving Therapy (BCT) module has not yet been translated into Canadian French. Given that French is an official language in Canada, a Canadian French adaptation is important to enable equitable participation in research. This study aimed to develop a linguistically accurate and culturally appropriate Canadian French translation of two scales from the BCT module. Methods: Two BREAST-Q BCT module scales (“Satisfaction with Breasts (Postoperative)” and “Adverse Effects of Radiation (Postoperative)”) were translated into Canadian French following established guidelines. The process included two independent forward translations, back translation, back translation review, and cognitive debriefing interviews with five breast cancer patients. Results: Forward translation identified three English words or phrases not amenable to direct translation, which were resolved by consensus prior to back translation. Cognitive debriefing interviews with breast cancer patients identified eight terms or expressions for refinement; five were incorporated into the final version based on majority patient feedback, including replacement of “tumorectomie” with “lumpectomie” to reflect terminology more familiar to patients. Conclusions: The Canadian French translation of the BREAST-Q BCT scales provides a linguistically and culturally adapted tool for assessing patient-reported outcomes in breast cancer care. Inclusion of patient feedback ensured clarity and relevance, supporting equitable participation in research and clinical outcome measurement.