Abstract PS1-57: Mastectomy versus breast conserving surgery for the management of locally advanced breast cancer
Bibliographic record
Abstract
Abstract Background: Breast conserving surgery (BCS) has become increasingly employed as a surgical option for patients with locally advanced breast cancer (LABC). However, guidelines on selecting appropriate LABC patients for BCS remain vague. Methods: Our Local Integrated Health Network (LHIN) conducted a multidisciplinary conference, known as the LHIN4 day, during which consensus criteria on which LABC patients may be safely offered BCS were established. These criteria included: clinical T3 or smaller, clinical and/or radiographic response to neoadjuvant therapy, patient seen by radiation oncology and deemed a candidate for post-operative radiation, and surgeon confident that negative margins could be achieved. A retrospective chart review was then performed of patients treated with neoadjuvant systemic therapy for LABC in the one year before, and three years after the LHIN4 day, which was between June 2015 and June 2019. Objectives: The primary objective of this study was to determine the rates of local and distant breast cancer recurrence in LABC patients treated with BCS using our consensus guidelines. The secondary objectives were: (1) to determine if there was an increase in BCS being performed following the LHIN4 educational day as compared to before this day, (2) to determine the rates of mastectomy followed by reconstruction among the patients treated within the past 3 years, and (3) to determine the rates of pathologic complete response (PCR). Results: A total of 391 patients were included in this study. Among the 26 patients who underwent BCS, the rate of local recurrence was 0% (0/26), and the rate of distant recurrence was 12% (3/26). Rates of BCS were 1.9% (2/108) before the LHIN4 day, and 8.5% (24/283) after the LHIN4 day. Rates of mastectomy followed by reconstruction were 12% (21/181) in the last 3 years. PCR was achieved in 15% (58/391) of all patients, of which 57% (33/58) were Her2 positive and 24% (14/58) were triple negative. Conclusion: We propose specific criteria for appropriately selecting LABC patients for BCS. Our results indicate that these criteria can be feasibly applied with low rates of local and distant breast cancer recurrence. A minority of patients with LABC who do not undergo BCS, either due to ineligibility or personal preference, are opting for mastectomy with reconstruction. Citation Format: Roochi Arora, Ghazaleh Kazemi, Graydon Lucas. Mastectomy versus breast conserving surgery for the management of locally advanced breast cancer [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS1-57.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.004 | 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 source (direct Gemma or distilled Codex), 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".