Primary Central Nervous System Lymphoma in Japan: a Nationwide Survey

Purpose: To analyze clinical features, treatment results, and prognostic factors of primary central nervous system lymphoma (PCNSL) in Japan, we conducted a nationwide survey.

Methods And Materials: We analyzed 466 patients with histologically proven PCNSL treated between 1985 and 1994 at 62 institutions, including 56 medical schools.

Results: Patient and tumor characteristics of the 466 patients were not greatly different from those reported previously, except for the relatively high proportion of T-cell lymphoma (8.5%). The median survival time of the 466 patients was 18 months, and the 5- and 10-year survival rates were 15.2% and 8.2%, respectively. Complete response was observed in 63% of evaluable patients, but 64% of the complete responders developed recurrence (77% within the irradiated volume). Among patient- or tumor-related factors, higher age, worse performance status, presence of B symptom, multiple lesions, presence of meningeal dissemination, and elevated lactate dehydrogenase (LDH) level were associated with poorer survival, whereas no significant difference was observed in prognosis with respect to sex, T/B phenotype, or histological subclassification. In 410 patients receiving at least 40 Gy to the tumor, there was no difference in survival with respect to total radiation dose or field. Patients receiving 2 or more cycles of systemic chemotherapy had a slightly longer median survival time (22 months) and higher 5-year survival rate (20%) than those receiving radiotherapy alone (18 months and 17%, respectively), but the difference was not significant (p = 0.13). No chemotherapy protocol appeared to be better than any other.

Conclusions: In addition to age and performance status, which are well-known prognostic factors, B symptom, tumor number, presence of meningeal dissemination, and serum LDH level also seemed to influence survival. Higher radiation dose was not associated with better prognosis. The role of chemotherapy could not be clarified because of the use of various protocols, but it seemed that the influence of various prognostic factors is greater than the effect of chemotherapy.