Patterns of relapse in large-cell lymphoma patients with bulk disease: implications for the use of adjuvant radiation therapy.

In patients with large-cell lymphoma (LCL) treated with combination chemotherapy, the presence of bulk disease has consistently been associated with a poorer response rate and a shortened survival. The optimal therapy for patients with bulk disease (greater than or equal to 10 cm) will depend on whether treatment failures result from inadequate tumor eradication in prior bulk sites or from distant dissemination. To address this issue, we have evaluated patterns of relapse in patients with bulk disease who relapsed after achieving a complete remission with methotrexate, bleomycin, doxorubicin, cyclophosphamide, vincristine, and dexamethasone (M- or m-BACOD). Eighty-one II, III, or IV patients with disease greater than or equal to 10 cm were identified; 45 of the 81 patients achieved a confirmed complete response (CR) and are included in the analysis. The 45 complete responders included 21 patients with localized (stage II) disease and 24 patients with advanced (stage III/IV) disease. Six of the 21 stage II complete responders and three of the 24 stage II/IV complete responders also received adjuvant radiation therapy following completion of M- or m-BACOD. Only one of the 21 patients with stage II disease relapsed, doing so in the site of prior bulk involvement. In contrast, nine of 24 patients with stage III/IV disease relapsed, although no patient failed solely in the site of prior bulk disease. Stage III/IV patients recurred in either a new site (one patient), a new and old site (five), an old non-bulk site (two), or both old non-bulk and bulk sites (one). These results indicate that advanced-stage bulk-disease patients do not consistently relapse in sites of prior bulk disease; therefore, this group of patients is unlikely to benefit from adjuvant radiation therapy administered following completion of combination chemotherapy. Although the low relapse rate and the addition of adjuvant radiation therapy in a subgroup of the stage II bulk-disease patients precludes a definitive analysis, our results further suggest that these patients may be effectively treated with combination chemotherapy alone.