Emerging Cancer Survival Trends, Disparities, and Priorities in Adolescents and Young Adults: A California Cancer Registry-Based Study

Abstract

Background: Although landmark studies in the 1990s demonstrated that adolescents and young adults (AYAs, ages 15-39 years) with cancer had lower survival improvement compared to other ages, therapeutic advances warrant reappraisal of those observations. We utilized more recent data to study site-specific AYA survival trends and disparities and gain a more contemporary understanding of this problem.

Methods: Using California Cancer Registry data from 1988 to 2014, we calculated 1) 5-year overall survival improvement for AYAs compared to other age groups; 2) hazard ratios (HRs) of death for AYAs comparing 2001-2014 with 1988-2000 stratified by site, stage, sex, age group, race and ethnicity, and socioeconomic status (SES); and 3) site-specific adjusted HRs (aHRs) for AYA risk groups and interaction analyses by time period.

Results: For all cancers combined, AYAs demonstrated survival improvement that exceeded all other age groups, largely due to reduced mortality in human immunodeficiency virus and acquired immunodeficiency syndrome-related cancers. The strongest predictor of death was cancer stage (aHR = 6.32 for distant vs localized, 95% confidence interval [CI] = 6.20 to 6.45). The aHR of death was statistically significantly higher for blacks (1.46, 95% CI = 1.42 to 1.50), Asian and Pacific Islanders (1.12, 95% CI = 1.09 to 1.15), and Latino whites (1.06, 95% CI = 1.04 to 1.08) compared to non-Latino whites, and was statistically significantly higher for low SES compared to high (1.31, 95% CI = 1.29 to 1.34). Survival disparities by stage, race and ethnicity, and SES worsened over time.

Conclusions: For AYAs in aggregate, the historical cancer survival improvement gap has been closed. However, the growing survival disparities in AYA subsets reported here, including advanced stage disease, racial and ethnic minorities, and low SES, highlight new priorities in need of increased attention, including inequities in cancer care and delivery within this vulnerable population.

Figure 1.

Absolute observed 5-year survival (lines) and survival difference (bars) of all invasive cancer by sex and age group at 5-year intervals, California, 1988–2000 to 2001–2014. A) All invasive cancers. B) All invasive cancers excluding Kaposi sarcoma. Absolute 5-year survival difference calculated by subtracting 1988–2000 5-year survival from 2001–2014 5-year survival. Invasive cancer is all cancers with invasive behavior code (excluding brain and central nervous system benign behavior code) and including bladder in situ. Shaded area indicates ages 15–39 years. All differences in survival between the two time periods (bars) meet statistical significance (see Supplementary Table 3, available online).

Figure 2.

Kaplan-Meier survival curves by time period for all cancers by site, adolescent and young adult, California, 1988–2000 and 2001–2014. Log-rank two-sided P values are reported. A) All cancers combined; B) bone and other soft tissue; C) brain and CNS: benign; D) brain and CNS: invasive; E) breast; F) cervix; G) colorectal; H) Kaposi sarcoma; I) kidney; J) leukemia: ALL; K) leukemia: AML; L) leukemia: CML; M) lip, oral cavity, and pharynx; N) lung; O) lymphoma: Hodgkin; P) lymphoma: non-Hodgkin; Q) melanoma; R) ovary: carcinoma; S) ovary: germ cell; T) stomach; U) testis; V) thyroid; W) uterus; X) other. Other indicates all noncategorized invasive cancers and benign intracranial tumors. See Supplementary Table 2 (available online) for cancer sites included in other. ALL = acute lymphocytic leukemia; AML = acute myeloid leukemia; AYA = adolescent and young adult; CML = chronic myeloid leukemia; CNS = central nervous system.