Purpose: To determine the optimal radiation dose in a localized non-Hodgkin's lymphoma of the head and neck in the treatment setting for combined chemoradiotherapy.
Materials and Methods: Fifty-three patients with stage Ⅰ and Ⅱ diffuse large cell non-Hodgkin's lymphoma of the head and neck, who were treated with combined chemoradiotherapy between 1985 and 1998 were retrospectively reviewed. The median age was 49 years, and the male-to-female ratio was approximately 1.6. Twenty-seven patients had stage Ⅰ disease and 26 had stage Ⅱ. Twenty-three patients had bulky tumors (≥5 ㎝) and 30 had non-bulky tumors (<5 ㎝). The primary tumors arose mainly from an extranodal organ (70%), most cases involving Waldeyer's ring (90%). All patients except one were initially treated with 3~6 cycles of chemotherapy, which was followed by radiotherapy. Radiation was delivered either to the primary tumor area alone (9%) or to the primary tumor area plus the bilateral neck nodes (91%) with a minimum dose of 30 ㏉ (range 30~60 ㏉). The failure patterns according to the radiation field were analyzed, and the relationship between the dose and the in-field recurrence was evaluated.
Results: The 10-year overall survival and the 10-year disease free survival rates were similar at 75% and 76%, respectively. A complete response (CR) after chemotherapy was achieved in 44 patients (83%). Subsequent radiotherapy showed a CR in all patients. Twelve patients (23%) had a relapse of the lymphoma after the initial treatment. Two of these patients had a recurrence inside the radiation field. No clear dose response relationship was observed and no significant prognostic factors for the in-field recurrences were identified because of the small number of in-field recurrences. However, for patients with tumors <5 ㎝ in diameter, there were no in-field recurrences after a radiation dose 30 ㏉. The 2 in-field recurrences encountered occurred in patients with a tumor ≥5 ㎝.
Conclusion: A dose of 30 ㏉ is sufficient for local control in patients with a non-bulky (<5 ㎝), localized, diffuse large cell non-Hodgkin's lymphoma when combined with chemotherapy. An additional boost dose in the primary site is recommended for patients with bulky tumors (≥5 ㎝).