Full dose vincristine (without 2‐mg dose limit) in the treatment of lymphomas

Background. Most current lymphoma protocols limit vincristine dose to 2 mg per single dose. Because a lower dose of vincristine may be associated with poorer outcome, there is some rationale to increase the dose of vincristine. Methods. The feasibility of full dose vincristine (i.e., 1.4 mg/m2 without 2-mg dose limit) was prospectively evaluated in lymphoma patients treated with various combinations. After an initial dose of 1.4 mg/m2, patients were carefully monitored, and dose was modified according to toxicity. Results. One hundred and four consecutive patients (31 with Hodgkin's disease and 73 with non-Hodgkin's lymphoma), aged 18–78 years were evaluated. The first dose was greater than 2 mg in 90% of the patients. The mean actual dose (percent of projected dose) was 100% in the first course and gradually decreased to 64% in the eighth course. The mean actual dose intensity of vincristine (percent of projected dose intensity) during the initial six cycles of prednisone, methotrexate, calcium leucovorin, doxorubicin, cyclophosphamide, etoposide, and mechlorethamine, vincristine, procarbazine, prednisone (ProMACE/MOPP), cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP), and MOPP/doxorubicin, bleomycin, and vinblastine (MOPP/ABV) was 82% and MOPP/doxorubicin, bleomycin, and vinblastine was 82%, 83%, and 87%, respectively. Symptoms of neuropathy developed in 92% of the patients and were usually of mild or moderate severity. Toxicity included World Health Organization (WHO) Grades 3 and 4 constipation in 10 (10%), and WHO Grade 3 peripheral neurotoxicity in 16 (15%) patients. Rapid improvement was usually noticed within a few weeks after withdrawal of vincristine. The median duration of symptoms from discontinuation of vincristine was 3 months for paresthesiae and motor weakness and 5 months for muscle cramps. Conclusions. Full dose vincristine in lymphoma protocols is feasible but is associated with increased toxicity. The therapeutic advantage of full dose vincristine has yet to be proven.