Is Radiation Necessary for Treatment of Non-Hodgkin's Lymphoma of Bone? Clinical Results With Contemporary Therapy.

BACKGROUND

Non-Hodgkin's lymphoma (NHL) of bone is a rare musculoskeletal malignancy accounting for fewer than 7% of bone cancers. Traditionally, we have treated patients who have NHL of bone with chemotherapy and radiation therapy, but the role of radiotherapy in disease management and patient functional outcomes after treatment have not been well studied. We investigated the survival advantage of radiotherapy in a large cohort of patients with NHL of bone and assessed associated patient complications of radiotherapy.

QUESTIONS/PURPOSES: The objective of this study was to compare patients treated for NHL of bone with and without radiation in terms of (1) overall survival; (2) pretreatment complications; (3) posttreatment complications; and (4) functional outcomes using the Musculoskeletal Tumor Society (MSTS) score.

METHODS

A retrospective analysis of all patients with biopsy-proven NHL of bone diagnosed at our institution between 1985 and 2013 was undertaken; 70 patients met our criteria for inclusion with minimum followup of 6 months (median, 55 months; range, 10-219 months). Overall survival at 5 and 10 years was estimated and compared between two groups of patients: one group treated with systemic therapy alone (chemotherapy, rituximab; 46 patients [66%]) and the other with combined modality therapy (systemic therapy and radiotherapy; 24 patients [34%]). During the period in question, indications for radiotherapy included bulky disease, an abbreviated course of systemic therapy, and an incomplete response to systemic therapy. Patients not meeting these criteria generally received systemic therapy alone. With the available sample size, it was estimated that a difference in survival of approximately 30% would have to be present for detection with 80% power (α = 0.05, β = 0.2, n = 70, Δ = 30%). Pretreatment and posttreatment complications occurring in both patient groups were retrospectively reviewed with special emphasis on fracture healing after treatment. MSTS scores were obtained for 45 patients with appendicular tumors at a median followup of 42 months (range, 10-215 months).

RESULTS

With the data available, no difference in Kaplan-Meier survivorship was observed between patients treated with and without radiation at 5 years (98%; 95% confidence interval [CI], 93%-100% versus 95%; 95% CI, 85%-100%; p = 0.281). Patients who were treated with radiation were more likely to experience problems with fracture healing (relative risk [RR], 12.8; 95% CI, 1.8-89.8; p = 0.01). Similarly, patients treated with radiation were at a higher risk for fracture in the posttreatment period (five of 24 versus no radiation zero of 46; RR, 20.7; 95% CI, 1.2-359.0; p = 0.0375). MSTS scores were poorer in patients treated with radiation (75% versus 91%; p = 0.034) attributable in part to a higher incidence of bony complications in this group after treatment.

CONCLUSIONS

Based on the numbers of patients in our study, we could not demonstrate a survival advantage with radiation use. Rather, radiotherapy may be associated with orthopaedic complications occurring during and after treatment. Larger, prospective studies are necessary to definitively establish whether radiation is necessary for the treatment of patients with lymphoma of bone.

LEVEL OF EVIDENCE

Level III, therapeutic study.