Low Dose Total Body Irradiation for Relapsed Low Grade Non-Hodgkin’s Lymphoma: Experience of National Cancer Institute, Cairo

Abstract

Background and Purpose: The relapsed low grade non-Hodgkin’s lymphoma (LG-NHL) is currently incurable disease and the optimal treatment regimen has not determined yet. Low dose total body irradiation (LTBI) provides an alternative mechanism of action against cancer cells rather than direct cell kill. The mode of action of LTBI is immune-modulatory effect, induction of apoptosis and hypersensitivity to low radiation doses. The aim of our study is to evaluate the effect of LTBI on relapsed LG-NHL and reporting our experience at National Cancer Institute, Cairo (NCI, Cairo). Material and Methods: Fifty eight patients with relapsed LG-NHL and received LTBI studied retrospectively. LTBI dose was 1.6 Gy/8 fractions divided on 2 courses; each course 4 fractions treated over 4 days with 2 weeks rest between the 2 courses. Results: The median age is 54 years; 65% of the patients are men. Forty (69%) patients had performance status of 2 or more. Twenty seven patients were stage II/III and 31 patients (53%) had stage IV disease. Twenty six (45%) patients had bulky disease more than 10 cm and 22 (38%) patients had B symptoms at the time of relapse. The extranodal disease was present in 17 patients (29%) and 78% of the patients received > 3 regimens of chemotherapy before referral to LTBI. Twenty three patients received IFRT (mean dose 32 ± 4 Gy) to initially bulky sites after LTBI. Fourteen patients (24%) achieved complete remission (CR) while 45%, 21% and 10% had partial remission (PR), stable disease (SD) and progressive disease (PD) respectively. The median PFS duration was 14 months and the median OS duration was 39 months. Stage VI, > 3 regimen of chemotherapy and bad response to LTBI (SD) affected progression duration adversely (0.03, 0.05 and 0.01 respectively). The response to LTBI is the only factor affected the OS duration significantly. The 3-year PFS was 19% ± 9%, and 3-year OS was 45% ± 8%. Stage IV was the only factor affected the 3-year PFS significantly with p value 0.03. The hematological toxicity was the main side effect of LTBI. Eleven patients developed G3/4 anemia while 8 patients only developed G3/4 thrombocytopenia and 13 patients developed G3/4 leucopenia. Conclusion: The use of LTBI in patients with relapsed low grade NHL is a feasible, effective and tolerable treatment that is worthy of testing in a future with chemotherapy and Rituximab maintenance.