Abstract 1056: Elevated incidence of rare cancers among solid organ transplant recipients (SOTRs) in the United States
Authors: Engels Eric , D'Arcy Monica , Pfeiffer Ruth , Shiels Meredith , Morton Lindsay , Kahn Amy , Lynch Charles 
Published: September 2020

Abstract
Background: SOTRs, like people with AIDS (PWA), have elevated rates of virus-related cancers. This is due to immunosuppression caused by anti-rejection medications. Cancer classification based only on organ site may mask rare cancer subtypes with distinct etiology that are elevated in SOTRs.
Methods: We used data from a linkage of the US SOTR registry with 17 population-based cancer registries. We categorized first cancers in SOTRs using a classification based on site and histology (Gatta, Eur J Cancer 2011). Standardized incidence ratios (SIRs) compared incidence in SOTRs to the general population.
Results: In a cohort of 262,455 SOTRs, we evaluated 694 cancer types, of which 33 had significantly elevated SIRs (Bonferroni p&lt;7.2E-05, Table). All 33 are rare and some have known viral etiology: Merkel cell carcinoma (SIR 24.7), leiomyosarcoma (26.5), and squamous cell carcinoma (SCC) of the anus (range 6.1-18.8), vulva/vagina (6.8), and penis (3.5). Other cancers with high SIRs include SCC of the lip (SIR 18.3-19.8), salivary gland (9.3), and conjunctiva (13.8); sebaceous adenocarcinoma (34.3); malignant fibrous histiocytoma (15.4); and subtypes of bladder and kidney cancers (10.3-13.3). Some of these cancers are also elevated in PWA to a lesser extent (Shiels, Cancer 2012).
Table:Standardized incidence ratios for cancers that occur at increased incidence among solid organ transplant recipientsCancer typeCasesSIR95% CIOral cavity/pharynxLip, SCC w/variants of lip, NOS2919.7913.2628.43Lip, SCC w/variants of lip, SCC16318.3015.6021.33Salivary gland, epithelial tumors, mucoepidermoid carcinoma184.322.566.82Salivary gland, epithelial tumors, SCC279.256.0913.45Oropharynx, SCC w/variants, SCC1612.231.902.60Digestive systemColon/rectum, adenocarcinoma, signet ring cell carcinoma314.453.026.31Anal canal, SCC, NOS1176.105.057.32Anal canal, SCC, verrucous carcinoma518.766.0943.78Liver and IBD, cholangiocarcinoma of IBD332.631.813.69Respiratory systemNasal cavity and sinuses, SCC, SCC214.472.766.83Lung, adenocarcinoma, mucinous adenocarcinoma213.211.994.91Lung, adenocarcinoma, papillary adenocarcinoma NOS193.552.145.54Soft tissueSarcoma of head and neck, leiomyosarcoma1226.5413.7146.36Sarcoma of head and neck, malignant fibrous histiocytoma815.416.6530.36Non-melanoma skin cancerAdnexal carcinoma NOS159.765.4616.10Adnexal carcinoma, malignant nodular hidradenoma720.398.2042.01Adnexal carcinoma, sclerosing sweat duct carcinoma613.394.9129.14Adnexal carcinoma, sebaceous adenocarcinoma6234.3426.3344.02Merkel cell carcinoma14024.6720.7529.11Soft tissue sarcoma536.464.848.45Breast, male302.351.593.36Genital systemVulva and vagina, SCC w/variants796.765.358.42Penis, SCC w/variants, SCC213.532.185.39Urinary systemBladder, adenocarcinoma NOS156.173.4510.18Bladder, adenocarcinoma, signet ring cell carcinoma610.593.8923.05Bladder, TCC, micropapillary714.185.7029.22Kidney, RCC, clear cell adenocarcinoma NOS3793.783.414.19Kidney, RCC, collecting duct carcinoma610.333.7922.48Kidney, RCC, papillary adenocarcinoma NOS32413.3011.8914.83Kidney, RCC, renal cell adenocarcinoma3963.653.304.03Kidney, RCC, RCC chromophobe type252.901.874.28Eye and adnexa, SCC, squamous carcinoma1613.757.8622.32NET, well differentiated endocrine tumors, carcinoid282.401.593.46Abbreviations: CI confidence interval, IBD intrahepatic bile duct, NET neuroendocrine tumor, NOS not otherwise specified, RCC renal cell carcinoma, SCC squamous cell carcinoma, SIR standardized incidence ratio, TCC transitional cell carcinoma
Conclusion: SOTRs experience elevated rates of selected rare cancers. Further characterization of cancers caused by immunosuppression and viral infections could facilitate prevention and treatment.
Citation Format: Eric Engels, Monica D'Arcy, Ruth Pfeiffer, Meredith Shiels, Lindsay Morton, Amy Kahn, Charles Lynch. Elevated incidence of rare cancers among solid organ transplant recipients (SOTRs) in the United States [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1056.