Long-term outcome, after first line intensified high-dose sequential (i-HDS) chemotherapy, was evaluated in 46 patients, aged < or =65 years, with advanced low-grade lymphoma. Seventeen patients had small lymphocytic lymphoma (SLL), 29 had follicular lymphoma (FL), 10 of them with histologic transformation. I-HDS included: (1) tumor debulking, by 2 APO+2 DHAP courses; (2) sequential administration of high-dose (hd) etoposide, methotrexate, and cyclophosphamide, followed by peripheral blood progenitor cell (PBPC) harvest; (3) hd-mitoxantrone + melphalan with PBPC autograft. Ten FL patients had their PBPC immunologically purged ex vivo. There were two treatment-related deaths; five FL patients had short-lasting response followed by disease progression, five SLL reached a stable PR; overall, 34 patients (74%) reached CR. At a median follow-up of 4.3 years, the estimated 9-year OS and EFS were 84% and 45%, respectively. No significant differences were observed in the OS among patients at low, intermediate or high IPI score, with an estimated OS projection of 95%, 78%, and 75%, respectively. FL had longer survival without evidence of residual disease (9-year EFS: 59%) as compared to SLL patients (8.8-year EFS: 17%); however, both groups had prolonged survival and no need of salvage treatment, as shown by the time to disease progression curve, projected to 66% and 62% for SLL and FL, respectively. The results indicate that hd-approach in low-grade lymphoma: (1) is associated with longer progression-free survival as compared to conventional therapies; (2) may imply higher tumor mass reduction in FL as compared to SLL patients; (3) offers long life expectancy, with potential survival benefits at least for patients at intermediate/high IPI score.