Lymphopenia assessed during routine follow-up after immunochemotherapy (R-CHOP) is a risk factor for predicting relapse in patients with diffuse large B-cell lymphoma

A specific predictor during routine follow-up to ascertain risk for relapse after standard chemotherapy in non-Hodgkin's lymphoma (NHL) has not been identified. Thus, we studied absolute lymphocyte count (ALC) as a marker of poststandard chemotherapy (rituximab, cyclophosphamide, adriamycin, vincristine and prednisone (R-CHOP)) NHL relapse in patients with diffuse large B-cell lymphoma (DLBCL). ALC was obtained at the time of confirmed relapse and at last follow-up. From 2000 until 2006, 149 consecutive DLBCL patients, originally diagnosed, treated with R-CHOP and followed up at Mayo Clinic, Rochester, were included in this study. Patients at last follow-up without relapse (N = 112) had a higher ALC compared with those with relapsed lymphoma ((N = 37) median ALC x 10(9)/l of 1.43 (range: 0.33-4.0) versus 0.67 (range: 0.18-1.98), P < 0.0001, respectively). ALC at the time of confirmed relapse was a strong predictor for relapse with an area under the curve = 0.91 (P < 0.0001). An ALC <0.96 x 10(9)/l at the time of confirmed relapse had a positive predictive value of 72% and a positive likelihood ratio of 7.4 to predict relapse after R-CHOP in DLBCL. Patients with an ALC >= 0.96 x 10(9)/l (N = 103) had a cumulative incidence of relapse of 6 versus 79% with an ALC <0.96 x 10(9)/l (N = 46) (P < 0.0001). This study suggests that lymphopenia measured by ALC can be used as a marker to assess risk of DLBCL relapse during routine follow-up after standard chemotherapy. Leukemia (2010) 24, 1343-1349; doi:10.1038/leu.2010.108; published online 20 May 2010