Cancer of unknown primary: Incidence rates, risk factors and survival among adolescents and young adults

Abstract

Cancer of unknown primary (CUP) is a clinical challenge especially when it occurs in adolescents and young adults (AYA), aged 15–39 years, due to the sparse data in this population. The available data has not described the population‐based epidemiological features of CUP among AYA. Therefore, we collected patient information from the Surveillance, Epidemiology and End Results (SEER) registry, 1990–2015. Age, gender, ethnic, five pathological classification groups were assessed along with an aggregate level socioeconomic status (SES) index and population density at the county level. Incidence rates, modeled relative risks and survival of AYA patients with CUP were assessed. Among 2,480 AYA patients, 907 met the definition of standard pathology classifications. The majority of AYA patients with CUP had a neuroendocrine, squamous cell and poorly differentiated carcinomas with 0.4 cases per 1,000,000 population. AYA living in areas with the highest SES level had the highest risks of CUP; adjusted relative risks (ARR) of 1.17 (95% CI 1.0–1.4) and 1.99 (95% CI 1.5–2.6), respectively. AYA living in nonmetropolitan areas had a lower risk of CUP (ARR = 0.16; 95% CI 0.1–0.2). The incidence of differentiated neoplasms has been decreasing slower than undifferentiated neoplasms since the early 1990s. The median overall survival (OS) was 11 months (95% CI 9–13 months) with squamous CUP having the longest median OS 16 years (95% CI 3–24 years). In conclusion, this analysis answers several gaps in the knowledge of CUP among AYA and provides a platform to better understand this disease and its management within this group.

Clinicopathological, molecular and prognostic characteristics of cancer of unknown primary in China: An analysis of 1420 cases

“…An epidemiological analysis reported that adolescents and young adults had a higher incidence of squamous cell carcinoma than the general CUP population (29% vs. 10%), which is consistent with our results. 26 Lymphatic metastasis is a relatively early process in distant metastasis and nodal metastasis for most solid tumors. Yilin et al found that the sentinel lymph node is the first stop of lymphatic spreading of CUP cases, which helps track the primary tumor, especially for well-differentiated tumors.…”

Integrated clinicomolecular characterization identifies RAS activation and CDKN2A deletion as independent adverse prognostic factors in cancer of unknown primary

“…Among histologic subtypes, adenocarcinoma was the predominant entity, but the study also included a substantial number of undifferentiated and squamous cell carcinomas. Only 12/252 (4.8%) of patients fell into the adolescent and young adults age group (15–39 years), among them nine with ≥36 years of age. The distribution of histologic subtypes in this young age cohort was comparable to the overall study cohort with adenocarcinoma as the leading subtype ( n = 8).…”

Global, Regional, and National Burden of Cancer in Children Younger Than 5 Years, 1990–2019: Analysis of the Global Burden of Disease Study 2019

“…The genetic and epigenetic aberrations in human cells are primarily attributable to the interaction of genetic and exogenous cancer risk factors ( 10 ). Cancers in children are likely linked to prenatal and congenital factors ( 11 ), with at least 10% of pediatric cancer patients harboring a germline mutation in a cancer predisposition gene ( 12 ). For instance, children with certain constitutional genetic abnormalities in the TP53 gene face an increased risk of acute lymphoblastic leukemia (ALL) ( 13 ); germline mutations in SUFU and PTCH1 have also been revealed as risk factors for infant medulloblastoma ( 14 ).…”