Supplementary Material for: Characteristics of Cancers in Adolescents and Young Adults Compared with Those in Adults in Their 60s: A Single-Center Experience

<b><i>Introduction:</i></b> Cancer is one of the main causes of death among adolescents and young adults (AYAs) aged 15–39 years. The improvement in overall 5-year survival in AYA cancer patients was far below than that of adult cancer patients. The purpose of this study was to clarify the features of cancer in AYAs by comparing them with those of controls. <b><i>Methods:</i></b> Patients in the cancer registry of the University of Tsukuba Hospital between 2007 and 2017 (median age, 65 years) were included in this study. We used patients between the ages of 64 and 66 years as controls. We then obtained the age at diagnosis, sex, primary site, and pathological type. <b><i>Results:</i></b> Among 27,281 cancer patients in the registry between 2007 and 2017, 1,947 (7.1%) patients were categorized into the AYA group, and 2,354 into the control group. Among men in the AYA group, central nervous system (CNS) tumors accounted for 22.7% of all cancers, followed by germ cell tumors, 22.5%, and hematopoietic malignancies, 12.5%. Among women in the AYA group, cervical cancer accounted for 35.9% of all cancers, followed by breast cancer, 14.6%, and CNS tumors, 11.6%. The proportion of specific cancer types relative to all cancers in the CNS, thyroid, adrenal glands, germ cells, cervix uteri, hematopoietic tissues, and sarcomas was higher in the AYA group than that in the control group. <b><i>Conclusion:</i></b> The present results for AYAs were in sharp contrast to those for adult cancers and may be related to different modes of pathogenesis in AYAs. The identification of high-risk groups of these tumors in the AYA generation is crucial for prevention and early detection and will be a major topic for future research. While most of adult cancers are treated independently by each medical department, AYA cancers need to be treated in collaboration with experts from several departments. It is desirable to address the issues involved in applying treatments established for adult cancers to AYA cancers on a cancer-by-cancer basis.

**引言**：癌症是15~39岁青少年与年轻成人（AYAs）的主要死亡原因之一。青少年与年轻成人癌症患者的整体5年生存率提升幅度，远低于成年癌症患者。本研究旨在通过与对照人群比较，明确青少年与年轻成人群体的癌症特征。
**方法**：本研究纳入2007年至2017年筑波大学附属医院癌症登记库中的患者（中位年龄65岁），以64~66岁的患者作为对照。研究收集了患者的确诊年龄、性别、原发部位及病理类型等信息。
**结果**：2007年至2017年期间，该登记库中共收录27281名癌症患者，其中1947例（7.1%）归入青少年与年轻成人组，2354例归入对照组。青少年与年轻成人组男性患者中，中枢神经系统（CNS）肿瘤占所有癌症的22.7%，其次为生殖细胞肿瘤（22.5%）与造血系统恶性肿瘤（12.5%）。该组女性患者中，宫颈癌占所有癌症的35.9%，其次为乳腺癌（14.6%）与中枢神经系统肿瘤（11.6%）。相较于对照组，青少年与年轻成人组中中枢神经系统、甲状腺、肾上腺、生殖细胞、子宫颈、造血组织及肉瘤相关的特定癌种占总癌症的比例均更高。
**结论**：本研究中青少年与年轻成人群体的癌症特征与成年癌症群体存在显著差异，这可能与该群体不同的发病机制相关。识别该群体中上述肿瘤的高危人群，对于疾病预防与早期筛查至关重要，也将成为未来研究的重点课题。多数成年癌症可由各临床科室独立开展诊疗，但青少年与年轻成人癌症需要多学科专家协作诊疗。针对成年癌症建立的治疗方案，需逐癌种评估其在青少年与年轻成人癌症患者中的适用性，并解决相关应用问题。