2ND MALIGNANT-TUMORS AFTER ELECTIVE END OF THERAPY FOR A FIRST CANCERIN CHILDHOOD - A MULTICENTER STUDY IN ITALY

To evaluate the incidence of second malignant tumors in a cohort of su bjects previously treated for childhood cancer, we analyzed data from the Off-Therapy Registry (OTR) of the Italian Association of pediatric Hematology/Oncology, which collects information on children treated f or Hodgkin's disease, non-Hodgkin's lymphoma, Wilms' tumor, acute lymp hoblastic leukemia (ALL) and acute non-lymphatic leukemia and who had been removed from treatment in the absence of clinical signs of diseas e, i.e. the off-therapy stage. Second malignant tumors (SMT), diagnose d before December 31, 1988, were identified through a special enquiry to the 36 institutions cooperating in the registry. Observed cases wer e compared to expected numbers estimated from age- and sex-specific in cidence rates derived from the Cancer Registry of the Province of Vare se. In a total of 3,3 10 study subjects, 27 SMTs have been registered. The Cumulative Risk (CR) of SMT was 2.9% 15 years after the end of tr eatment and the Standard Incidence Ratio (SIR) was 10.8. The ALL sub-c ohort had the highest risk of SMT (SIR 13.6) and 9 cases of CNS tumor occurred in this group (SIR 58.9). All 9 had received prophylactic cra nial radiotherapy (CRT) and 5 had been treated on one protocol, charac terized by low-dose intrathecal methotrexate (IT MTX) given monthly fo r 2 years after CRT. The Off-Therapy Registry has unique criteria for inclusion; direct comparisons with similar studies are therefore somew hat problematic. However, our data suggest that the risk of SMT in chi ldhood ALL cancer survivors may be greater than previously reported, a nd that CNS tumors are the most common SMT in this group. The administ ration schedule of IT MTX may be an important risk factor. (C) 1994 Wi ley-Liss, Inc.