Primary lymphoma of bone: a prospective study of 28 cases

To conduct a prospective study of primary lymphoma of bone (PLB) comparatively with extraskeletal non-Hodgkin's lymphomas (ESNHLs) and secondary lymphoma of bone (SLB).

The 28 cases of PLB, 2932 cases of ESNHL, and 219 cases of SLB included between April 1, 1993, and October 1, 1997, in a treatment protocol for NHL developed by the Adult Lymphoma Study Group, were studied prospectively.

Of the 28 PLB patients, 17 were men and 11 women; median age was 48 years (range, 18-69). The disease was monostotic in 17 cases (involving the peripheral skeleton in 14) and polyostotic in nine cases. The proportion of patients younger than 60 years was 86% in the PLB group, 59% in the ESNHL group, and 55% in the SLB group. The Ann Arbor stage distribution (I-II/III-IV) was as follows: 54%/46% in the PLB group, 50%/50% in the ESNHL group, and 20%/80% in the SLB group. Performance status was 0 or 1 in 100% of the PLB patients, 50% of the ESNHL patients, and 20% of the SLB patients. The phenotype was B in 89% of the PLBs and 85% of the ESNHLs and SLBs. In the PLB group, 54% of patients had diffuse large cell tumors and 11% diffuse mixed tumors; in the ESNHL group, 39% had diffuse large cell, 13% diffuse mixed, and 8% diffuse immunoblastic tumors; and in the SLB group, 45% had diffuse large cell, 10% diffuse mixed, and 12% diffuse immunoblastic tumors. A complete or partial response to induction therapy was noted in 86% of PLB patients, 84% of ESNHL patients, and 78% of SLB patients. Overall five-year survival was 65% in the PLB group, 50% in the ESNHL group, and 40% in the SLB group.

Survival was better in the PLB group. Further studies are needed to determine the effect of radiation therapy at completion of the treatment protocol and to look for prognostic factors associated with bone involvement.