Influence of dose intensity and density on therapeutic and toxic effects in Hodgkin's disease

From 1972 to 1976, 95 patients with clinical stages I-IIIA Hodgkin's disease were treated by chemotherapy with cyclophosphamide, vinblastine, procarbazine and prednisone (CVPP) before and after extended field radiotherapy. The CVPP schedule gave: (1) a constant drug dosage for each patient independent of body surface or weight; and (2) a total drug dosage dependent on haematological tolerance, since the treatment was given for 21 days or until the leukocyte count dropped to 2 x 10(9) l-1. The drug dosage per unit body surface (or 'dose density') significantly correlates with the drop in leukocyte count (P less than 0.001) and the tumour regression at the end of the induction course (P = 0.020). Disease-free survival is significantly related to dose density (P = 0.050) but not to dose intensity calculated on the duration of treatment (P = 0.240). However, after exclusion of three marginal recurrences due to border-line radiotherapy, the dose intensity significantly correlates with the disease-free survival (P = 0.031) and with the duration of complete remission (r = 0.870).