This and future reports are written by oncologists from Pacific Shores Medical Group (a large group practice in Long Beach, California). The reports are primarily based on notes taken at the American Society of Clinical Oncology
ABSTRACT: This and future reports are written by oncologists from Pacific Shores Medical Group (a large group practice in Long Beach, California). The reports are primarily based on notes taken at the American Society of Clinical Oncology annual meeting (San Francisco, May 2001). The reports include a summary of the presentations at ASCO, plus our own impressions (shown in italic type) of the clinical significance of the studies. The information is intended to help you get updated on new developments in oncology. The coverage of the meeting is not meant to be comprehensive, but rather focused on highlights that we consider most interesting or relevant. We hope these reports will be of some value to the readers of Oncology News International.
Maintenance With Rituximab Improves Response
In abstract #1175, Dr. John Hainsworth presented results on the treatment of indolent low-grade non-Hodgkin’s lymphoma (NHL) with rituximab (Rituxan) given as induction followed by maintenance cycles every 6 months. Sixty-two patients were entered in this study from 1998 through 1999, and the response rate is very favorable with minimal side effects. Interestingly, the response rate has increased after additional maintenance courses of rituximab, and two thirds of the patients are free of progression at 2 years for both follicular and small lymphocytic histologies. The authors indicated that repeated courses of rituximab at 6-month intervals improved responses in 30% of patients without increasing the toxicity.
Early-Stage Primary Gastric Lymphoma
Abstracts #1186 and #1187, presented by Dr. P. Koch from Germany and Dr. B. Pro from Texas, respectively, discuss results with regard to the treatment of early-stage primary gastric lymphoma with nonsurgical therapies. Dr. Koch presented an analysis of a database of about 370 patients and concluded that primary chemotherapy or a combination of chemotherapy and irradiation is very effective primary therapy and that surgery for these early lesions does not improve outcome, but is associated with toxicity and morbidity due to the effects of gastrectomy. Dr. Pro presented results on 45 patients treated with chemotherapy, with or without radiotherapy for stage I and II gastric lymphoma. Dr. Pro reported that 43 of 45 patients (95%) achieved a complete remission, and the projected 5-year overall disease-specific survival was 90%. Importantly, however, there were two treatment-related deaths (4%), one with sepsis and the other with gastrointestinal bleeding, both of which were on treatment. Dr. Pro concluded that chemotherapy with or without radiation therapy is associated with high response rates and excellent survival in early-stage primary gastric lymphoma, thus avoiding the complications of surgery.
Our impression from these two trials is that primary chemotherapy with or without irradiation is a reasonable option for early-stage primary gastric lymphoma. One has to be very careful, however, and individualize the therapy, particularly in trying to avoid the risk of perforation and local bleeding. These risks are real and need to be considered in a multidisciplinary approach with close consultation with the gastroenterologist and the surgeon.
Primary Paranasal Sinus Lymphoma
Dr. Janessa Laskin from Canada (abstract #1188) presented results on the use of central nervous system (CNS) chemoprophylaxis with intrathecal chemotherapy in patients with primary paranasal sinus lymphoma. This disease is an uncommon presentation of extranodal lymphoma that is associated with a high risk of CNS involvement. Indeed, in this series of 44 patients analyzed retrospectively since 1980, the authors observed that the risk of CNS recurrence or involvement declined from 40% prior to the institution of intrathecal chemotherapy in 1984 down to only 8% after 1984. In fact, intrathecal prophylaxis was also associated with an improvement in overall survival from 20% to 50%.
Clearly, the addition of prophylactic intrathecal chemotherapy is supported by these compelling data in patients with primary paranasal sinus lymphoma.
Radioimmunotherapy in Heavily Pretreated Bulky Rituximab-Refractory NHL
Dr. I.W. Flinn presented results of ibritumomab tiuxetan (Zevalin) radioimmunotherapy in heavily pretreated bulky rituximab-refractory NHL patients (abstract #1141). Zevalin is an anti-CD20 murine IgG1 kappa antibody bound to an yttrium isotope. In this clinical trial, Zevalin was administered to 57 NHL patients refractory to rituximab. Patients were excluded if they had more than 25% bone marrow involvement by lymphoma. The toxicity was mainly hematologic and reversible. Myelotoxicity reversed in 1 to 2 weeks. Seven percent of patients had neutropenic febrile episodes. Seventy-four percent had objective remissions, and even patients with large bulky masses responded. Zevalin appears to be a very promising agent in the treatment of these patients.
In a related presentation, Dr. C. Emmanouilides from UCLA (abstract #1143) presented data on Zevalin in geriatric patients with low-grade follicular or CD20-positive transformed NHL. The treatment consisted of rituximab given for 2 doses 1 week apart followed by yttrium-labeled Zevalin. The study pooled the experience in 211 patients, 65 years or older, being treated for NHL. The treatment was well tolerated and, in this older patient population, there was no statistical difference in safety, compared with patients less than 65 years of age. The primary toxicity was hematologic, transient, and reversible. Efficacy was also not compromised. The authors felt that Zevalin is safe in this population of older patients.