Abstract P1-12-03: Metaplastic carcinoma of the breast: A single-center 18-year series of 73 cases
Bibliographic record
Abstract
Abstract Background: Metaplastic breast cancer (MeBC) is a rare subtype accounting for 0.2%-5% of all invasive breast cancer. They are characterized by an aggressive course and even a worse prognosis than triple-negative breast cancer (TNBC). The literature suggests that MeBCs are relatively chemoresistant; still, the patients often receive adjuvant or neoadjuvant chemotherapy during the course of treatment. This study aimed to examine the clinical management of MeBC, particularly the role of chemotherapy. Methods: This retrospective study included patients with MeBC (n=73) from the Centre des Maladies du Sein du CHU de Québec-Université Laval. The specimens were reviewed by two pathologists. Patient and tumor characteristics, systemic therapy (neoadjuvant and adjuvant), disease-free survival (DFS), and overall survival (OS) were recorded. Results: The median follow-up was 57.2 months. The mean tumor size was 39.5±32.1 (range, 1-200) mm. The vast majority had grade 3 (76.7%), no evidence of clinical nodal involvement (78.1%), and triple-negative (79.5%) disease. This population included one case (1.4%) of low-grade adenosquamous breast carcinoma, one (1.4%) of fibromatosis-like metaplastic carcinoma, 11 (15.1%) of spindle cell carcinoma, 13 (17.8%) of epidermoid carcinoma, 18 (24.7%) of MeBC with heterologous mesenchymal differentiation, and 29 (39.7%) of mixed MeBC. Chemotherapy was given to 53 (72.6%) patients. Thirty-seven patients (50.7%) had a lumpectomy, and 34/37 (91.9%) received adjuvant radiotherapy. Thirty-six patients (49.3%) had mastectomy and 22/36 (61.1%) received radiotherapy. The 5-year DFS was 55.6%, and the 5-year OS was 63.5 %. On univariable analyses, higher cT stage (cT3-4) was associated with poorer DFS and OS compared to cT1-2, respectively 13.4% vs. 70.7% (P<0.0001) and 19.9% vs. 82.8% (P<0.0001). Nodal involvement significantly influenced DFS (31.3% vs. 63.0%, P=0.011) and OS (37.5% vs. 71.6%; P=0.009). Lumpectomy was associated with a better 5-year DFS (78.4% vs. 34.0%, P<0.0001) and OS (90.6% vs. 38.8%, P<0.0001). The use of chemotherapy had a significant positive effect on 5-year DFS (64.2% vs. 31.9%, P=0.006; hazard ratio (HR)=0.45, 95% confidence interval (CI)=0.22-0.92, P=0.009) as well as 5-year OS (69.7% vs. 45.1%, P=0.035; HR=0.52, 95%CI=0.28-0.95 P=0.041). However, radiation therapy did not influence DFS (P=0.420) and OS (P=0.316). Nine patients received neoadjuvant chemotherapy; five had nodal involvement. One patient had a complete response (11.1%), five (55.6%) had a partial response, and three (33%) had progressive disease. The 5-year DFS and OS were lower for neoadjuvant chemotherapy compared with adjuvant chemotherapy (DFS: 27.8% vs. 71.5%, P=0.006; OS: 33.3% vs. 79.2%, P=0.001), but disease was more advanced in patients with neoadjuvant chemotherapy (cT3-4: 88.9% vs. 11.9%, P<0.0001). Conclusion: MeBC represents a rare heterogeneous group of malignancies with poor prognosis. Chemotherapy was associated with improved DFS and OS. Patients for neoadjuvant chemotherapy should be carefully selected. Citation Format: Kassandra J Thériault, Mariem Ben Moussa, Marjorie Perron, Christine Desbiens, Brigitte Poirier, Éric Poirier, Dominique Leblanc, Claudya Morin, Julie Lemieux, Jean-Charles Hogue, Dominique Boudreau. Metaplastic carcinoma of the breast: A single-center 18-year series of 73 cases [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P1-12-03.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.005 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".