165P Introduction of Magseed in the DGH setting: No inferiority to wire localisation
Bibliographic record
Abstract
Wire guided localization is the gold standard technique for pre-operative localization of non-palpable breast cancers in patients undergoing wide local excision (WLE). It has logistical challenges as it needs to be performed on the day of surgery, requiring coordination of Breast, Radiology and Theatre teams. Reported complications include wire displacement, intra-operative difficulty localizing the tip, pneumothorax, and cardiac injuries. Magseed is an alternative localization technique using a magnetic seed, which can be placed up to 30 days pre-operatively. This is localized intraoperatively with a ‘Sentimag probe’. The iBRA-NET Localisation Study performed in UK demonstrated magseed localization as an effective technique in terms of patient convenience and satisfaction, accurate localisation and avoiding unnecessary scheduling delays/cancellations. Our breast unit changed from using wires to predominantly Magseed localisations in early 2020. Data was retrospectively collected for all patients undergoing wire or Magseed localised WLE for non-palpable invasive breast cancer or ductal carcinoma-in-situ from 01/10/2019 to 01/10/2020. Accuracy was determined by the presence of cancer and wire/Magseed in the specimen or cavity shave, presence of clear margins, and need for re-excision. Complications within 30 days of surgery were also recorded. Statistical analysis was performed using IBM SPSS statistics version 24 (Univariate analysis). P values under 0.05 were considered significant. Table: 165PMagnetic seed (n=43)Wire (n=49)p-valuep-value in national auditAccurate localization42 (97.7%)48 (97.9%)0.7300.048*Re-operation rate8 (18.6%)13 (26.5%)0.4580.574Positive/Close margins9 (20.9%)9 (18.4%)0.7970.342Specimen weight34g (7.70-378.3g)29g (5.5-201.4g)0.3620.362Minor wound infection320.1470.170Major wound infection (needing IV antibiotics)100.3520.527Unexpected re-admission to hospital within 30 days100.7210.676Peri-operative problemMagseed/wire dislodged from lesion100.4670.039*Index lesion/clip not visible on specimen X-ray310.2610.406Type of surgeryWide local excision37480.032*0.002*Therapeutic mammoplasty51Other (LICAP)10 Open table in a new tab Results are shown in the table below. Magseed can be introduced safely into the DGH setting, with non-inferior results compared to wire localisations. The technique has advantages for both patients and scheduling teams. Our findings support those of the National Localization Audit.
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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 | 0.005 |
| 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) | 0.010 | 0.002 |
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".