SYNCHRONOUS AND METACHRONOUS DIAGNOSIS OF MULTIPLE PRIMARY CANCERS

Aims: In the time period near to the diagnosis of a new cancer, other tumors (synchronous cancers), especially slow-growing tumors, may be d etected because several diagnostic examinations are performed. The fre quency of synchronous in comparison with metachronous carcinomas has b een evaluated in a population-based series of multiple primary cancers , Methods: The case series of multiple primary cancers of the Tuscany Tumor Registry, incident during the period 1985-1991 was analyzed. For each site of a second independent tumor, the proportions of synchrono us (diagnosed within 2 months of the first primary) and metachronous c ancers were compared with the mean distribution (all sites except the specific one). Results: During 1985-1991, 1095 patients had two indepe ndent tumors diagnosed; 216 were synchronous. The proportion of synchr onous compared to metachronous cancers was significantly higher for bl adder, prostate and renal cell carcinomas; it was significantly Tower for lung cancer. When cancers following skin epitheliomas were evaluat ed, only the proportion of synchronous skin cancers was significantly increased. Conclusions: Silent slow-growing tumors are suspected to be more frequent in patients with prostate, bladder or renal cell carcin omas. In fact, they were most frequently diagnosed during ascertainmen t for another cancer. When few examinations were performed, as after t he diagnosis of a skin epithelioma, no difference between metachronous and synchronous cancers was evident, except for skin.