Sex ratio among childhood cancers by single year of age

Abstract

Background The male excess in childhood cancer incidence is well‐established; however, the underlying biologic mechanisms remain unknown. Examining the association between male sex and childhood cancer by single year of age and tumor type may highlight important periods of risk such as variation in growth and hormonal changes, which will inform etiologic hypotheses. Methods Using data from the Surveillance, Epidemiology, and End Results (SEER) 18 registries (2000–2015), incidence rate ratios (IRR) and 95% confidence intervals (95% CI) were estimated as the measure of association between male sex and childhood cancer by single year of age (0–19). Results The IRR for male cancer overall was 1.19 (95% CI, 1.18–1.20) and was similar in magnitude at nearly every year of age. Burkitt lymphoma was strongly associated with male sex (IRRs ≥2 at each year of age). Increased incidence was observed among males for acute lymphoblastic leukemia, Hodgkin and non‐Hodgkin lymphomas for nearly all years of age. Medulloblastoma was the only central nervous system tumor with a significant male predominance at nearly every age. Male sex displayed a consistent inverse association with nephroblastoma and thyroid carcinoma over the ages studied. Conclusions Male sex was positively associated with most cancers. The higher incidence rates observed in males remained consistent over the childhood and adolescent periods, suggesting that childhood and adolescent hormonal fluctuations may not be the primary driving factor for the sex disparities in childhood cancer. The observed incidence disparities may be due to sex differences in exposures, genetics, or immune responses.

Childhood cancer incidence among specific Asian and Pacific Islander populations in the United States

“…A male excess of childhood cancer, especially among NHWs, has been well described in the literature 49 . In addition, this pattern has been seen at the global level, including, a previous report from Steliarova‐Foucher et al, 28 which collected data from hundreds of registries worldwide and found a global excess in cancer among males.…”

Male Sex and the Risk of Childhood Cancer: The Mediating Effect of Birth Defects

“…For some cancers, we observed age-dependent variation in our results when comparing analyses of the entire study population with subgroup analyses among children younger than 5 years and younger than 1 year of age. It is well established that the sex ratio among childhood cancer cases differs by age ( 1 ). Analyses of the birth defect and cancer associations have also seen age-dependent results, with stronger effect estimates for younger age at cancer onset ( 3 , 7 ).…”

“…The unexpected sex ratios are likely because of the lower linkage success rates of older cancer cases. In osteosarcoma and Ewing sarcoma occurring at younger than 18 years of age, the male excess is due almost entirely to adolescent cases; there is nearly no difference in sex ratio among younger cases ( 1 ). Despite this limitation, we do not expect that early life migration is differential by birth defects status or child sex, as noted above.…”

“…It is well established that males have a higher risk of childhood cancer compared with females ( 1 ). This male excess in incidence is observed for most major tumor types and the overall male-to-female incidence rate ratio for all childhood cancers is 1.19 (95% confidence interval [CI] = 1.18 to 1.20) ( 1 ), with a range for specific cancers from 1.13 (astrocytoma and neuroblastoma) to 4.62 (Burkitt lymphoma). The tumors with a female preponderance are nephroblastoma (Wilms tumor), extracranial and extragonadal germ cell tumors, and thyroid carcinoma.…”

Comparison of Hodgkin’s Lymphoma in Children and Adolescents. A Twenty Year Experience with MH’96 and LH2004 AIEOP (Italian Association of Pediatric Hematology and Oncology) Protocols

“…It is well known that the male gender is related to most cancers, and it is strongly associated with each type of lymphoma, including HL. This suggests a role of gender itself in hematologic tumors connected to genetic and immune-related factors, rather than hormonal variations, which better relate to bone tumors and germ-cell tumors (GCTs) [ 19 ]. Our patient population is predominantly male, except for adolescents in the most recent protocol, where the male-to-female ratio showed an increase in girls with age, similarly to other publications [ 18 , 20 , 21 , 22 , 23 ].…”