Impact of oral mucositis on outcomes of multiple myeloma patients treated with high-dose melphalan conditioning and autologous stem cell transplantation (ASCT).

Abstract

7037 Background: High-dose melphalan is the standard conditioning regimen for patients with multiple myeloma (MM) undergoing ASCT. However, this therapy is commonly associated with severe oral mucositis (OM). Low-level laser therapy (LLLT) has been reported as an effective method in preventing this complication. The aim of this study was to define the potential impact of OM on outcomes in patients with MM undergoing ASCT and receiving preventive LLLT. Methods: We describe a retrospective cohort of 79 consecutive patients with MM who received high-dose melphalan conditioning. All patients received prophylactic LLLT application performed daily from the beginning of the conditioning regimen up to day +2. The patients continued receiving LLLT in case of OM grade ≥ 2 until complete remission of the lesions. OM severity was assessed daily using WHO scale from the beginning of conditioning until hospital discharge. We examined the relationship between worst OM grade and clinical outcomes, including days with oral pain, days of total parenteral nutrition, days of LLLT and days with neutropenic fever. Results: Of 79 patients, 55 (69.62%) experienced OM grade 0-1, 16 (20.25%) experienced OM grade 2, 7 (8.86%) grade 3 and 1 (1.26%) grade 4. Patients with OM grade 0-2 had statistically fewer days of oral pain compared with grade 3-4 (0.88 and 6.25 days, respectively, p = 0.0001). The worst OM grade was also significantly (p < 0.05) associated with days of narcotic therapy and length of LLLT. Severe OM was not associated with febrile days or the use of parenteral nutrition. Conclusions: Severe OM is associated with worse clinical outcomes. In this transplantation setting, severe OM was not common as previously reported in literature, probably due to LLLT. Controlled randomized trials should be performed to confirm the real benefit of LLLT in this scenario as well as the pharmacogenomics and pharmacokinetic studies to better understand interpatient variability of melphalan exposure and toxicity.