Jan. 16 (HealthDay News) -- Treatment that combines the monoclonal antibody rituximab with six cycles of chemotherapy improves survival in elderly patients with aggressive lymphoma, German doctors report.

Their research was published in the Jan. 15 online issue of The Lancet Oncology. The study was expected to appear in the February print issue of the journal.

Researchers studied 1,222 patients aged 60 to 80 with diffuse B-cell lymphoma and found that six cycles of CHOP-14 chemotherapy (cyclophosphamide, doxorubicin, vincristine, and prednisolone) combined with eight applications of rituximab (R-CHOP-14) was as effective as eight cycles of CHOP-14 chemotherapy alone.

Dr. Michael Pfreundschuh, of the Saarland University Medical School in Homburg, and his colleagues noted this means elderly patients can be spared the toxicity and side effects of two additional cycles of chemotherapy.

The study found that three-year, event-free survival was: 47.2 percent after six cycles of CHOP-14; 53 percent after eight cycles of CHOP-14; 66.5 percent after six cycles of R-CHOP-14; and 63.1 percent after eight cycles of R-CHOP-14.

Three-year overall survival was: 67.7 percent for six cycles of CHOP-14; 66 percent for eight cycles of CHOP-14; 78.1 percent for six cycles of R-CHOP-14; and 72.5 percent for eight cycles of R-CHOP-14.

"Six cycles of R-CHOP-14 significantly improved event-free, progression-free, and overall survival over six cycles of CHOP-14 treatment. Response-adapted addition of chemotherapy beyond six cycles, though widely practiced, is not justified," the researchers wrote. "Of the four regimens assessed in this study, six cycles of R-CHOP-14 is the preferred treatment for elderly patients, with which other approaches should be compared."

This diffuse lymphoma is an aggressive type of non-Hodgkin's lymphoma. More than half of patients with this type of lymphoma are more than 60 years old.

SOURCE: The Lancet, news release, Jan. 14, 2008