Residual tumor masses following treatment for advanced histiocytic lymphoma. Diagnostic and therapeutic implications.

Forty percent or more of patients with advanced diffuse histiocytic (large cell) lymphoma will achieve prolonged disease-free survival with the use of intensive combination chemotherapy. These results are obtained only if complete resolution of all viable tumor is documented prior to the cessation of chemotherapy. Residual tumor masses at the time of re-staging usually are excised or biopsied to confirm the presence or absence of viable tumor. Three patients are reported who had with advanced histiocytic (large cell) lymphoma, and who demonstrated residual intra-abdominal tumor masses on CT scan following four courses of COPP chemotherapy. After two additional courses of a non-cross-resistant regimen and/or supplemental radiotherapy failed to reduce the size of the masses, abdominal exploration with removal of the tumors including splenectomy in one patient was performed, and in each instance no viable tumor was found. The patients have remained disease-free for periods ranging from 24 to 48 months. The various options available to evaluate such patients are presented, and a systematic approach which should avoid the unnecessary prolongation of potentially harmful chemotherapy or radiotherapy is proposed.