Patterns of the risk for subsequent primary cancer among survivors of adult-onset cancers in the United States.

Abstract

12060 Background: The number of cancer survivors who develop new cancers is projected to grow in the US. Few studies, however, have provided a comprehensive overview of the contemporary pattern in the risk of subsequent primary cancer (SPC) among survivors of adult-onset cancers. Herein, we evaluate overall and type-specific risks of SPCs among adult-onset cancer survivors by first primary cancer types and sex. Methods: We assessed the excess risk of SPCs among 1,442,374 persons aged 20-84 years who were diagnosed with first primary cancers from 1992-2010 and survived ≥5 years in the 12 Surveillance, Epidemiology, and End Results registries. We expressed the risks using excess absolute risk (EAR) per 10,000 person-years and standardized incidence ratio (SIR) by first primary cancer types and sex, compared to those expected in the general population. We also estimated percent contributions of each specific type of SPCs to the total EAR for all first primary cancers combined by sex. Results: The overall risk of SPCs was higher than expected for 24 of the 34 first primary types among male survivors and for 28 of the 35 first primary types among female survivors. The greatest SIR and EAR were estimated after laryngeal cancer in both men (SIR = 1.74, 95%CI = 1.67-1.82; EAR = 159.3, 95%CI = 143.6-175.5) and women (SIR = 2.48, 95% CI = 2.26-2.73; EAR = 202.7; 95%CI = 171.8-236). There were 290 type-specific associations with significantly higher risk of SPC, 36% of which being reciprocal, predominantly among smoking-associated, HPV-associated, and hematologic cancers. The SIRs in men ranged from 1.05 (95%CI = 1.00-1.10; EAR = 1.69) for lung/bronchus cancer after colorectal cancer to 73.9 (95%CI = 58.3-92.3; EAR = 23.3) for anal cancer after Kaposi sarcoma; and in women the SIRs ranged from 1.08 (95%CI = 1.02-1.15; EAR = 0.36) for pancreatic cancer after breast cancer to 19.9 (95%CI = 15.0-26.0; EAR = 39.5) for oral cavity/pharyngeal cancer after laryngeal cancer. For all first primary cancers combined, lung/bronchus cancer comprised the greatest proportion of the total EAR of SPCs, 34.6% in men and 29.1% in women, followed by urinary bladder (11.8%) and oral cavity/pharynx (7.5%) in men and by corpus uterus (12.9%) and colorectum (7.6%) in women. Conclusions: Despite the substantial heterogeneity in the risk of SPCs across the first primary types, only a few cancers comprised a considerable proportion of the total excess risk among survivors. Better understanding of contributing factors to these patterns will inform survivorship care plans and care delivery.