The lower peripheral blood lymphocyte/monocyte ratio assessed during routine follow-up after standard first-line chemotherapy 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 first-line chemotherapy in non-Hodgkin's lymphoma (NHL) has not been identified, although blood counts, lactate dehydrogenase (LDH) and imaging studies, such as computed tomography (CT) scans or positron emission tomography, have been recommended. Therefore, we studied the absolute lymphocyte count/absolute monocyte count ratio (ALC/AMC ratio) as a marker of poststandard first-line chemotherapy for predicting relapse in patients with diffuse large B-cell lymphoma (DLBCL). 220 consecutive DLBCL patients, originally diagnosed, treated with CHOP or R-CHOP and followed up at two institutions. ALC/AMC ratio was obtained at the time of confirmed relapse or last follow-up. Patients at the time of confirmed relapse (n = 163) had a lower ALC/AMC ratio compared with those at last follow-up (n = 57) (P < 0.001). ALC/AMC ratio at the time of confirmed relapse was a strong predictor for relapse with an area under the curve = 0.813 (P < 0.001). The sensitivity and specificity for ALC/AMC ratio at the time of confirmed relapse or at last follow-up were 68.1% and 87.7%, respectively, and the relative risk of relapse with an ALC/AMC ratio < 2.8 at the time of confirmed relapse or at last follow-up was 1.845 with an odds ratio of 15.247 (95% cumulative incidence: 6.473-35.916) after CHOP or R-CHOP in DLBCL. Patients with an ALC/AMC ratio (< 2.8) had a higher cumulative hazard rate of relapse compared with an ALC/AMC ratio (≥2.8) (P < 0.001). This study suggests that the lower ALC/AMC ratio can be used as a marker to assess risk of DLBCL relapse during routine follow-up after standard first-line chemotherapy.