Event free survival at 24 months: A new endpoint in diffuse large B-cell lymphoma

Background: The monoclonal antibody rituximab has changed the natural history of Diffuse Large B-cell Lymphoma (DLBCL). Recent data show that patients with DLBCL achieving EFS24 (event-free survival at 24 months) after treatment with immunochemotherapy have a normal life expectancy. We have explored what happens in our patient population. Methods: We reviewed our database of patients with lymphoma treated between 1987 and 2011. We selected DLBCL patients who had received a minimum follow up of 5 years. We included 228 patients in the analysis; 100 had received rituximab based treatment and 128 did not receive any antibody. We studied the pattern of relapse and event-free survival at 12 and 24 months from diagnosis in both populations. Results: Our data show that the pattern of relapse in DLBCL patients has changed in the post-rituximab era. There are fewer relapses (24% versus 33%, p = 0,04) but those who relapse do so earlier: 75% of relapse occur in the first two years and late relapse (after 5 years) are rare (less than 8%) in rituximab treated patients. Patients who achieve EFS12 have a better prognosis than patients who did not achieve it (80% OS 5 years versus 15%, p < 0,001) but patients who achieve EFS24 have a very good prognosis compared to patients who do not achieve EFS24 (p < 0,001), regardless of the treatment received (90% versus 15% OS at 5 years, p < 0,001). Comparing EFS12 and ESF24, ESF24 is a better prognostic tool to determine long term survival. Conclusions: Most of the patients who relapse after immunochemotherapy do so early, probably linked to a different biological behavior of the tumor. Patients who achieve EFS24 have a very good prognosis. We need to perform an accurate follow up with patients in the first 2 years after diagnosis to detect early relapses and focus on studying the molecular biology of these tumours to detect differences in relapsed patients. Follow up after 5 years from diagnosis will detect only a small account of relapses and probably will not impact on survival. Legal entity responsible for the study: Hospital Puerta de Hierro Majadahonda Funding: None Disclosure: All authors have declared no conflicts of interest.