Inward, David J.

Abstract Background: Germinal center B cell-like (GCB) DLBCL, as determined by gene expression profiling or immunohistochemistry, is more likely to be cured by initial conventional chemoimmunotherapy than non-germinal center B cell-like (non-GCB) DLBCL. For patients with relapsed or refractory chemosensitive DLBCL, high-dose chemotherapy and autologous hematopoietic stem cell (HSC) transplant is considered standard-of-care treatment, but it is unknown whether the outcome of these patients is similarly influenced by the subtype of DLBCL. We therefore explored the differences between patients with GCB and non-GCB DLBCL as regards their clinical features at relapse after first line therapy and their outcome following salvage autologous HSC transplant. Methods: Patients undergoing BEAM conditioning and autologous HSC transplantation for relapsed or refractory chemosensitive DLBCL at Mayo Clinic, Rochester, MN between 2001 and 2006 were included. Immunohistochemical analysis was performed for CD10, BCL-6 and MUM1 allowing classification in GCB and non-GCB-like DLBCL, as well as for BCL-2. GCB and non-GCB groups were compared in terms of known prognostic factors at time of progression and outcome after HSC transplant Results: Fifty-nine patients were included and had retrievable tumor samples to allow immunohistochemical analysis. Median follow-up of survivors was 25 months; median age at the time of transplant was 60 years (range 17–77); All patients had failed at least one previous anthracycline-based regimen (15 had refractory disease). Overall, 25/59 cases (42%) were positive for CD10, 32/58 (55%) for BCL-6, and 19/58 (32%) for MUM1. Thirty-two patients (54%) were classified as having GCB and 27 (46%) non-GCB-like DLBCL. Patients in the GCB and non-GCB group had similar time to progression (TTP) (median 12.5 months vs. 11 months, Wilcoxon P=0.81) after first line therapy and similar IPI-R scores (Chi-square, P=0.38). In univariate analysis, GCB and non-GCB did not differ in time to relapse after HSC transplant (log rank test P=0.77) or survival (log rank test P=0.48; figure). The lack of demonstrable difference in survival persisted even after correction for IPI-R and TTP, factors know to affect transplant outcome (Cox regression, RR=0.80 for GCB; P=0.28). BCL-2 was highly expressed in both GCB (81%) and non-GCB (96%) and did not correlate with outcome in the entire population nor in any of the two groups. Conclusion: Patients with chemosensitive relapsed or refractory GCB and non-GCB-like DLBCL derive similar benefit from autologous HSC transplant. Figure Figure

Background: High-dose chemotherapy and hematopoietic stem cell (HSC) transplantation is considered standard therapy in patients with chemosensitive relapsed diffuse large B cell lymphoma (DLBCL). BCNU, etoposide, cytarabine and melphalan (BEAM) is a standard widely used DLBCL conditioning regimen. Chemotherapy doses, both standard and high dose, are traditionally based in body surface area (BSA) and are often calculated using the corrected ideal body weight. However, this practice is empirical and the best way to dose chemotherapy is unknown. Weight-based dosing has been suggested to better predict toxicity of the conditioning regimen. We correlate the BEAM dose/actual weight ratio with toxicity and overall outcome in a uniform cohort of patients receiving HSC transplant for relapsed DLBCL Methods: Retrospective analysis of 80 consecutive patients treated at Mayo Clinic, Rochester, MN between 2001 and 2006 who received a HSC transplant following BEAM conditioning was performed. All doses were based on BSA calculated using the corrected ideal body weight. Weight-based dose intensity was retrospectively calculated utilizing the melphalan dose/Kg as a surrogate for the entire regimen. Weight-based dose intensity was correlated with toxicity in the first 30 days after transplant and survival outcome. Results: Median age at the time of transplant was 62 (interquartile range 53–65; range 26–77); 65% were males; median number of prior chemotherapy regimens was 2. Median dose of melphalan was 3.2 mg/Kg (interquartile range 2.9–3.6; range 2.2–4.5). Only one patient died within 30 days of the transplant. Patients who received > 3.6 mg/Kg of melphalan were more likely to have Grade 3 or 4 mucositis (44.4% v. 9.8%, P=0.001) than the remaining patients. Median numbers of days spent in the hospital in the first 30 days after transplant was 13 (3–18) for melphalan dose >3.6 mg/kg vs. 7 (0.5–10.5) for the remaining patients (P=0.043). Weight based dose intensity did not correlate with survival (P=0.8) or disease-free survival (P=0.3). Conclusion: Weight based dose intensity of BEAM correlates with toxicity post autologous HSC transplant. Patients receiving doses corresponding to >3.6 mg/kg of melphalan are at increased risk of high-grade mucositis and prolonged hospitalization. Figure Figure