Organ transplant recipients are at increased risk of a wide range of malignancies, especially cutaneous squamous cell carcinomas (SCC). Few previous population-based studies have quantified and compared cancer risks according to graft type and with long-term follow-up. Using nationwide Swedish registers, we identified 10,476 recipients transplanted from 1970 to 2008 and followed them for cancer occurrence. Relative risks of cancer in comparison with the general population were expressed as standardized incidence ratios (SIR) and within the transplanted cohort as incidence rate ratios (IRR). During a total follow-up of 93,432 person-years, patients were diagnosed with 1,175 cancers excluding SCC, and with 2,231 SCC, SIR cancer excl SCC 2.4 (95% CI, 2.2-2.5); SIR SCC 121 (95% CI, 116-127). Cancer risks were most increased among heart and/or lung recipients SIR cancer excl SCC 3.3 (95% CI, 2.8-4.0); SIR SCC 198 (95% CI, 174-224), followed by kidney SIR cancer excl SCC 2.3 (95% CI, 2.1-2.4); SIR SCC 121 (95% CI, 116-127) and liver recipients SIR cancer excl SCC 2.3 (95% CI, 1.9-2.8); SIR SCC 32 (95% CI, 24-42). During follow-up, risk of cancer excluding SCC remained stable while risk of SCC tripled over 20 years irrespective of graft type, partly due to a subgroup of patients developing new SCCs at a rapidly increasing rate. In summary, posttransplant cancer risk varied by transplanted organ and by cancer site, with the bulk of the excess risk driven by an exceptionally high and accelerating risk of SCC. These findings underscore the importance of regular skin screening in organ transplant recipients.

This study suggests a general but not universal increase in the incidence of tongue SCC worldwide. In some regions of the world, we observed a shifting trend toward women and/or younger patients. © 2016 Wiley Periodicals, Inc. Head Neck 39: 297-304, 2017.

Given the preponderant period effect and the abrupt onset observed or inferred in most populations, the epidemic appears to be caused by some exposure that was first introduced around 1950. At least 30 years' variation in estimated time of onset opens prospects for hypothesis-generating ecological analyses.

In this study we aimed to identify cancers where there is a consistent sex disparity, with the goal of identifying unexplained sex disparities that may offer promising opportunities for etiologic research. Age- and sex-specific cancer incidence data from Cancer Incidence in Five Continents, provided by the International Agency for Research on Cancer, were used to calculate incidence rate ratios for 35 cancer sites, comparing men to women, adjusting for attained age, gross domestic product (GDP), and geographical region. Genital cancers and breast cancer were excluded. The consistency of relative risks was examined by GDP and geographical region and, in a subset of longstanding cancer registers, by calendar year. For each cancer site, the sex disparity was broadly classified as plausibly explained by established environmental risk factors, partly explained, or unexplained. Cancer incidence was statistically significantly higher in men than women at 32 of 35 sites, with disparities >2-fold for 15 sites and >4-fold for 5 sites. For nearly all sites, the sex disparity was consistent across GDP groups and geographical regions. However, the incidence rate ratios varied considerably by age at diagnosis. The sex disparity for 13 cancer sites was considered to be entirely unexplained by known risk factors; these sites showed strikingly little variation in the incidence rate ratios over decades. Thus, the basis of many of the largest sex disparities in cancer incidence seems mostly unknown, highlighting the need for intensified research into its origins.