Times Not to Forget Radiotherapy When Treating Patients With Lymphoma

Charles A. Enke, MD


J Oncol Pract. 2019;15(4):167-172. 

In This Article

Primary Testicular Lymphoma

Primary testicular lymphoma (lymphoma involving one or both testes at diagnosis) is a rare condition comprising 0.6% of all lymphoma cases in the United States. Diffuse large B-cell lymphoma (DLBCL) accounts for approximately 78% of primary testicular lymphoma cases.[8] Gundrum et al[9] conducted a SEER database analysis covering the timeframe 1980 to 2005, involving 769 patients with DLBCL presenting as primary testicular lymphoma. Seventy percent of patients had stage I (56.6%) and stage II (13.4%) presentations. Radiation therapy was used in 35.9% of all stages or slightly more than 50% of patients with stage I and II disease.[9] In a separate retrospective international survey of 373 patients diagnosed with primary testicular DLBCL, there was an observed continuous risk of recurrence in the contralateral testis of 15% at 3 years and 42% at 15 years in patients who did not receive radiotherapy to the contralateral testis (P = .003).[10] The International Extranodal Study Group-10 trial was subsequently conducted as a multicenter phase II prospective study evaluating use of the triweekly rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone regimen in combination with intrathecal methotrexate and local regional radiation therapy for the treatment of primary testicular lymphoma. Radiation therapy was delivered to the remaining contralateral testis to a dose of 25 to 30 Gy along with involved field radiation therapy to other sites of disease. There were no failures observed in the contralateral testis with the addition of radiation therapy.[11] The literature frequently discusses radiation therapy to the contralateral testis. This terminology refers to the common practice of performing an orchiectomy on the involved testis, with radiation therapy used to treat the remaining contralateral testis. From a practical standpoint, the entire scrotum is usually irradiated, including the remaining testicle or both testes if present. The International Lymphoma Radiation Oncology Group guidelines for extranodal lymphoma has additional details regarding the radiation technique. The recommended radiation dose is 25 to 30 Gy at 1.5 to 2 Gy per fraction.[6] Although treatment is usually done with an anterior electron beam field with bolus, dosimetric coverage may be optimized in some patients using nonparallel opposed photon fields.