Sixty-six cases of
multiple primary neoplasms in children in Japan were collected, including 8 cases of our own. These could be divided into 19 synchronous and 47 metachronous multiple
neoplasms. Metachronous or
multiple primary neoplasms comprised
leukemia,
osteosarcoma, mesenchymal
sarcoma, epithelial
carcinoma and others in contrast to
synchronous neoplasms which consisted of many pairs of embryonic
tumors. The presumptive factors for
multiple primary neoplasms suggested
radiotherapy-associated
cancers in 30%,
radiochemotherapy-associated in 13%,
chemotherapy-associated in 34%, and genetic factor-related in 36% of cases. Chromosomal analysis was performed in 12 cases. Three of 4
leukemias revealed major karyotypic abnormalities in the leukemic cells. No 13q14, deletion was detected in 5 cases with
multiple primary neoplasms developed with
retinoblastoma. Frequent incidence of sister chromatid exchange (SCE) was detected in cultured fibroblasts or lymphocytes from one of 3 cases of
second primary neoplasms associated with
chemotherapy. The time interval between both
neoplasms ranged from 2 to 15 years in the majority of cases.
Chemotherapy-associated
multiple primary neoplasms seemed to appear more quickly than
radiotherapy-associated
multiple primary neoplasms. Seven children out of 459 long-term survivors of childhood
cancer developed
multiple primary neoplasms during the period from 5 to 20 years after diagnosis of the first
tumor at the National
Cancer Center Hospital, Tokyo. The relative risk was suggested to be 14 times higher than the expected incidence of childhood
cancer in Japan. Refinement of treatment, long-term monitoring and protective procedures for high-risk patients against
multiple primary neoplasms are therefore warranted.