Management and Outcomes for Primary Mediastinal B-Cell Lymphoma Patients with Partial Metabolic Response
Bibliographic record
Abstract
Background: The optimal management of patients with primary mediastinal B-cell lymphoma (PMBCL) who experience a partial metabolic response (PMR) on FDG-PET after initial systemic therapy is unclear. This study aimed to investigate different management strategies and outcomes for PMBCL patients who achieved PMR following primary systemic therapy, utilizing a single-center retrospective design. Methods: We reviewed the electronic medical records of 121 PMBCL patients who underwent post-chemotherapy PET scans at the Princess Margaret Cancer Center, Toronto, from January 2009 to September 2021. Using Modified Lugano criteria (2014), post-chemotherapy PET scan results were evaluated, with Deauville score (DS) 0-3 considered a complete metabolic response. Demographic, clinical, and imaging characteristics of the PMBCL population were analyzed. The Kaplan-Meier method was used to estimate progression-free survival (PFS), measured from the time of the post-systemic therapy PET. Results: A total of 121 patients with PMBCL underwent post-chemotherapy PET scans. Among them, 49 patients (40%) demonstrated incomplete metabolic response (DS4-5) Among these 49 patients, 12 showed primary refractory disease, while 37 demonstrated a partial metabolic response (PMR, DS4). The median age at diagnosis of the 37 patients with PMR was 30.8 years (range:18.4 - 52.8 years), and 20 (54%) were female. The median length of follow-up for these patients was 3.7 years (range: 0.4 to 9.2 years). Most PMR patients were stage I/II (26 patients, 70.3%), while the remaining were stage III (2 patients, 5.4%), or stage IV (8 patients, 21.6%), and 26 (70.3%) had a large mediastinal mass (maximum diameter exceeding 10cm). Initial systemic treatment was R-CHOP-21 (34 patients, 91.9%), R-CHOP combined with dose-adjusted R-EPOCH (2 patients, 5.4%), and dose-adjusted EPOCH (1 patient, 2.7%). Thirty one patients (83.8%) received 6 cycles. Following treatment strategies were employed to manage PMR: 1) radiation therapy (RT) only with or without biopsy in 30 patients (80.1%); 2) an observational approach (repeating PET scans without immediate treatment) in 3 patients (8.1%); 3) salvage chemotherapy in 3 patients (8.1%) and other approach in 1(2.7%) patient. The 2-year progression-free survival (PFS) rate for all patients with incomplete metabolic response (n=49) was 74.5% (95% CI = 62.5% to 88.9%). For patients with primary progression on post-chemotherapy PET scans the 2-year PFS (ie free of 2nd progression) was 40% (18.7% to 85.5%), while the 2-year PFS for patients with PMR was 85.4% (74.3% to 98.1%). PMR patients who underwent radiotherapy (RT) had the 2-year PFS rate of 92.7% (95% CI: 83.5% to 100.0%). No progression or relapsed occurred among the 3 patients with PMR who were managed with repeating PET scans without immediate further treatment. Conclusion: This study replicates prior work demonstrating a higher rate of incomplete metabolic response for PMBCL patients following R-CHOP-21 than typically reported for DLBCL. RT to persistent PET-avid sites is associated with excellent PFS. The favorable outcome of PMR patients without any additional treatment illustrates the non-trivial risk of false-positive PET scans following systemic therapy, and the need to identify criteria that can distinguish those who need additional treatment from those who can be safely observed.
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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 | 0.000 | 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) | 0.001 | 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".