Diffuse large B-cell lymphoma: sites of extranodal involvement are a stronger prognostic indicator than number of extranodal sites in the rituximab era

The National Comprehensive Cancer Network (NCCN) International Prognostic Index (IPI) is an enhanced prognostic tool that has identified some specific extranodal sites as a poor prognostic factor. We retrospectively analyzed 148 Taiwanese patients with newly diagnosed diffuse large B-cell lymphoma receiving rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone (R-CHOP)-like regimens from January 2001 to December 2010 at the Tri-Service General Hospital. In univarate analysis, ≥ 2 extranodal involved sites had no significant prognostic relevance (p = 0.108), although extranodal involvement of the lung/pleura, liver, lower urinary tract or bone marrow was a statistically significant poor prognostic factor (p < 0.001). In multivariate analysis, specific extranodal sites had a stronger predictive value for poor prognosis (relative risk 3.654, 95% confidence interval 1.514-8.815, p = 0.004) compared with the number of extranodal sites involved. This finding suggests that specific extranodal involved sites have prognostic value in the R era.