Multiple primary cancer: an increasing health problem. Strategies for prevention in cancer survivors.

This study was set to look for associations between the sites of the first and subsequent tumours in patients with multiple primary cancer (MPC) diagnosed from 1975 to 2002 in the reference hospital of a Spanish northern region, and propose prevention strategies. Patient and tumour variables were measured. Crude and standardized incidence rates per 100 000 inhabitants were obtained, and the association between MPC incidence and time was analysed by means of lineal regression. Relative risks were calculated to analyse associations between tumour sites. A total of 2737 MPC cases were registered (male/female ratio = 2). The percentage of MPC with respect to the total cancer increased from 1.78% in the 1975-1979 period to 7.08% in the 2000-2002 period (R(2) = 0.92; P = 0.003). Great increase of incidence by time was found (R(2) = 0.90; P = 0.004). Breast, prostate and bladder cancers increase risk of second tumour in female genital organs [RR 4.78 (3.84-5.93)], urinary system [RR 3.69 (2.89-4.69)] and male genital organs [RR 3.76 (2.84-4.69)] respectively. The MPC incidence is increasing. Interventions for MPC prevention, according to the European Code against Cancer, should be implemented early after the first cancer principally if patients suffer breast, bladder, prostate, larynx and colon cancers.