Identification of occult brain metastases amenable to stereotactic radiosurgery by motexafin gadolinium (MGd) based treatment planning MRI: Results of a phase II trial of MGd and whole brain radiotherapy (WBRT) with stereotactic radiosurgery (SRS)
Bibliographic record
Abstract
2037 Background: Motexafin gadolinium (MGd) is a novel anti-cancer agent that selectively localizes in tumors and is detectable by MRI. Previous studies of patients (pts) with brain metastases (BM) demonstrated the detection of occult lesions after MGd administration not visible with gadolinium MRI contrast. The purpose of this study was to evaluate if MRI scanning after MGd improves SRS treatment-planning and treatment outcome by identifying and better defining lesions that can be treated with the SRS boost. Methods: Pts with 1–4 BM (< 4 cm diameter, or, if multiple, < 3cm) received WBRT (37.5 Gy) and MGd, 5 mg/kg/day during weeks 2–3 of WBRT, plus MGd, 5 mg/kg prior to treatment planning MRI and prior to SRS (21 Gy for lesions = 2 cm, 18 Gy for lesions 2.1–3.0 cm, and 15 Gy for lesions 3.1–4.0 cm). MRI was obtained within 4 weeks prior to enrollment with standard contrast, and after WBRT for SRS treatment planning with MGd and standard contrast. Patients were followed for neurologic progression and survival. Results: 45 patients with either lung cancer (76%), breast cancer (11%), melanoma (7%), or other cancers (7%), a median age of 58 years (range 42–74), and a median of 2 BM (range 1–4) were evaluable. In 9 of 42 patients (21%) with MRI data available, the MGd-based treatment planning MRI demonstrated at least one occult lesion not visualized on the screening MRI. The MGd-based treatment planning MRI detected 1 occult lesion in 6 pts, 2 occult lesions in 1 patient, and 3 occult lesions in 2 patients. Median survival for evaluable pts is 10 months; median time to neurologic progression or radiologic progresssion is not reached at 15 months. Grade 3+ neurotoxicity was limited to 1 pt with tumor necrosis and 1 pt with motor weakness. Most common Grade 3+ adverse events were pneumonia (9%) and DVT (9%). Conclusions: MGd-based treatment planning MRI for SRS identified occult BM that are amenable to SRS and are undetected with standard gadolinium contrast agents in 21% of the pts enrolled in this phase II trial. Treatment with MGd, WBRT and SRS to all lesions visualized resulted in improved survival and local control compared with historical results. [Table: see text]
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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".