Low-Dose Radiotherapy Effective, Safe With Concurrent Chemo for Relapsed/Refractory MCL
Low-dose radiation therapy (RT) is effective for patients with relapsed/refractory mantle cell lymphoma (MCL), and safe for use concurrently with chemotherapy, according to results from a study published in Blood Advances (2019;3[13]:2035-2039).
“[MCL] generally exhibits an aggressive disease course with poor outcomes. Despite inherent radiosensitivity,…RT…is not commonly used for MCL,” explained Matthew S. Ning, MD, Department of Radiotherapy, University of Texas MD Anderson Cancer Center, Houston, and colleagues, who assessed the role of low-dose RT along with chemotherapy in this patient population.
A total of 19 patients with relapsed/refractory MCL treated at 98 disease sites with 4 Gy were included in the study.
Median follow-up after initial low-dose RT was 15.4 months, and patients received a median of 7 courses of chemotherapy since diagnosis. Of the 19 patients included in the study, 58% were refractory to ibrutinib.
Overall 76% of the 98 disease sites were refractory to ongoing chemotherapy. Low-dose RT was administered along with chemotherapy to this 76%.
The rate of complete response (CR) was 81% at a median of 2.7 months after receipt of low-dose RT. Despite patients having disease refractory to ibrutinib, >5 chemotherapy courses, or tumor size >3 cm, Dr Ning and colleagues noted that there was no difference in CR.
No RT-related toxicities were reported. The 1-year overall survival rate after initial low-dose RT was 90% and the 1-year progression-free survival rate after the last course was 55%.
“In summary, LDRT [low-dose RT] is effective for relapsed, multiply refractory MCL, and may be safely delivered with chemotherapy, to multiple sites, and repeatedly without issue. By treating active sites of disease, LDRT can provide durable local control, help achieve remission, and potentially bridge patients to subsequent novel therapies,” concluded Dr Ning and colleagues.—Janelle Bradley
