Sentinel Node Biopsy in Melanoma Using Technetium-99m Rhenium Colloid: The London Experience
Bibliographic record
Abstract
Nodal metastases in patients with melanoma identify a reduction of survival by 50%; however, elective lymph node dissection (ELND) has not been shown clearly to improve survival. Morton's technique of sentinel node biopsy, using preoperative lymphoscintigraphy and intraoperative blue dye, addresses elegantly the controversy regarding ELND. Sentinel node biopsy has been shown to stage the patient accurately because metastases from melanoma follow an orderly progression from the sentinel node to the remainder of the basin. Fifty-six consecutive patients with American Joint Committee on Cancer stage 1b or 2 melanoma seen at the London Health Sciences Center between July 1998 and January 2000 were enrolled prospectively to undergo sentinel node biopsy. Preoperative lymphoscintigraphy was conducted in the nuclear medicine department. A total of 10 to 15 MBq (0.27-0.41 mCi) of technetium 99m (99mTc) rhenium colloid or filtered sulfur colloid was injected intradermally around the biopsy scar. Images were obtained to localize all draining nodal basins. The location of the sentinel node was marked on the skin. The patient was taken to the operating room and anesthetized. Isosulfan blue dye was injected intradermally around the biopsy scar. A hand-held gamma probe was used intraoperatively as a guide to the first draining node. Blue-stained lymphatic channels aided in the dissection. Sentinel node localization was successful in 55 of 56 patients, for an overall success rate of 98%. Preoperative lymphoscintigraphy identified a sentinel node in an unpredictable location in 32% of patients. On average, 2.3 sentinel nodes per patient were identified on the initial scan, and 2.2 sentinel nodes per patient were recovered at surgery. Both 99mTc rhenium and filtered sulfur colloid showed no substantial differences in tracer uptake and retention in the sentinel node. Twelve patients had a positive sentinel node on routine histology, and 11 patients subsequently underwent completion lymphadenectomy. The mean thickness of the primary melanoma in the 12 patients with positive sentinel nodes was 3.7 mm compared with a mean tumor thickness of 1.8 mm in the remaining 41 patients with negative biopsies (p = 0.0003). Two patients experienced recurrence in a regional basin after negative pathological evaluation of the sentinel node. Reverse transcription-polymerase chain reaction analysis of both of these patients was positive. Two patients are alive with metastatic disease and 54 patients are alive without disease, with a mean follow-up of 1 year (range, 2-24 months). Complications occurred at a substantially higher rate (45%) after completion lymphadenectomy than after sentinel node biopsy alone (9%). Sentinel node biopsy is a feasible technique with a high success rate (98%), but it requires a multidisciplinary approach. This study validates the clinical usefulness of 99mTc rhenium colloid for lymphoscintigraphy.
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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 | 0.001 |
| 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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
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".