Although considered a rare occurrence in adolescents and young adults (AYAs), aged 15 to 39 years, the incidence of cancer in this age group has been increasing by approximately 30% since the 1970s. This year, it is estimated that nearly 90,000 new cases of cancer will be diagnosed in this population and nearly 9,200 AYAs will die from the disease.

A new study by Berkman et al published in Cancer Epidemiology, Biomarkers & Prevention investigating long-term mortality patterns among 5-year AYA leukemia survivors—specifically survivors of acute lymphocytic leukemia (ALL) and acute myeloid leukemia (AML)—found that the 10-year survival of AYA leukemia survivors was approximately 10% lower than that of the age-adjusted general population in the United States. Additionally, these differences persisted for up to 30 years of follow-up. Research investigating the factors placing AYA survivors at risk for late morbidity and mortality is needed to develop surveillance strategies and reduce risk factors, according to the study authors.

Study Methodology

The researchers used data from the Surveillance, Epidemiology, and End Results (SEER) registry to assess the long-term outcomes of AYA acute leukemia survivors who were alive 5 years after diagnosis. They obtained information for 1,938 ALL survivors and 2,350 AML survivors for the years 1975 to 2011, and assessed the differences in lifespan between the ALL and AML cohorts and a U.S. national cohort obtained from the National Vital Statistics Reports.

As long-term survival by decade of diagnosis was assessed, patients were excluded whether they were diagnosed prior to 1980 or after 2009, as data spanning the entire decade of diagnosis was not available for the 1970s or 2010s.

Among the ALL survivors, 6% were Black, 29% were Hispanic, 7% were Asian or Pacific Islander, and 58% were White. Among the AML survivors, 9% were Black, 22% were Hispanic, 10% were Asian or Pacific Islander, and 59% were White. The median age of diagnosis was 23 years for ALL survivors and 28 years for AML survivors. Median follow-up times from diagnosis were 12.3 and 12.7 years for ALL and AML, respectively.

The impact of diagnosis, age, sex, race/ethnicity, socioeconomic status, and decade of diagnosis on long-term survival were assessed utilizing an accelerated failure time mode.

Results

The researchers found that the 10-year survival for ALL and AML survivors was 87% and 89%, respectively, and 99% for the general population. Survival for AYA leukemia survivors remained below that of the age-adjusted general population at up to 30 years of follow-up. Primary cancer mortality was the most common cause of death, becoming more prevalent in later decades of follow-up.

Male AML survivors had significantly worse survival than female AML survivors (survival time ratio = 0.61, 95% confidence interval = 0.45–0.82).

“AYA leukemia survivors have higher mortality rates than the general population that persist for decades after diagnosis,” concluded the study authors.

The Impact of Disease and Late Side Effects From Treatment

Michael Roth, MD

“Some of these patients aren’t being fully cured of their initial cancer,” said senior study author Michael Roth, MD, Associate Professor, Co-Director of the Adolescent and Young Adult Oncology Program, and Director of the Childhood Cancer Survivorship Program at The University of Texas MD Anderson Cancer Center, in a statement. “So, between 5 and 10 years post–initial diagnosis, most of the deaths are due to disease progression or relapse, whereas after that, most of the deaths result from late side effects from treatment, including cardiovascular disease and secondary cancers…. While we anticipate we will see more durable cure rates due to recent new treatments, it’s hard to know whether the number and intensity of late side effects will decrease.”

Disclosure: Funding for this study was provided by National Cancer Institute, the Archer Foundation, and LyondellBasell. For full disclosures of the study authors, visit aacrjournals.org/cebp.