Historically 15- to 39-year-olds have been treated like an overlooked middle child whose parents are too busy lavishing cancer prevention and therapeutic attention on the youngest and oldest, but the Keck School of Medicine of USC is looking to change that dynamic with a first-of-its-kind report card.

Published this year, “Cancer in Los Angeles County: Trends Among Adolescents and Young Adults 1988-2011” is a large-scale, comprehensive evaluation of the cancer trends of 15- to 39-year- olds, said Dennis Deapen, lead author of the report and director of the Los Angeles Cancer Surveillance Program.

“There has been tremendous improvement in survival of pediatric cancer patients over the last three decades,” Deapen said. “Thirty years ago, 80 percent of pediatric cancer patients died of their disease. Now over 80 percent are cured. Yet in what we define as the ‘AYA population,’ between the ages 15 and 39, there has been no overall improvement in their survival.”

Cancer is the leading cause of non-accidental death among adolescents and young adults, according to the report card. An estimated 71,180 AYAs were diagnosed with cancer in 2011 — seven times more than those under the age of 15. Los Angeles County doctors identify cancer in about 2,600 AYAs each year, according to the January report.

USC is a leader in tackling intractable problems such as cancer. For the past 44 years, the Los Angeles Cancer Surveillance Program has tracked every diagnosed case of cancer. Keck Medicine of USC and the USC Norris Comprehensive Cancer Center oversee the program.

Hypotheses to consider

Lack of health insurance, paltry clinical trial participation and adherence to treatment, and differences in tumor biology are a few of the hypotheses for why improvements in modern medicine has been of little or no benefit to the AYA group.

“It is a vulnerable point in human development characterized by uncertainty and change — probably the worse possible time for a disease like cancer to enter their world as a very ‘uninvited guest,’” said Stuart Siegel, former director of the Adolescent and Young Adult Cancer Program at the USC Norris Comprehensive Cancer Center (AYA@USC). “By focusing on the population of AYA cancer patients in Los Angeles County with its highly diverse composition and especially large population of Hispanic patients, the authors provide new insights into the characteristics and needs of this population of patients that make up a growing percentage of our nation’s people.”

Second only to age and gender, race and ethnicity is the strongest predictor of differences in cancer risk, Deapen said.

“Part of the reason the general population is unaware of this ‘AYA Gap’ is fortunately, this population has a relatively low rate of cancer; however, that’s also the challenge,” Deapen said. “The numbers are small enough that unless you come to a population like Los Angeles County, the numbers get so small that it’s really hard to spot trends or make survival analyses. I’m eager to see investigators, clinicians, researchers at USC and elsewhere use our data to begin to answer the question of why cancer survival is not improving among 15- to 39-year-olds.”

Between Jan. 1, 1988 and Dec. 31, 2011, 62,355 AYA cancers were newly diagnosed among Los Angeles County residents. Some of the key findings were as follows:

  • Testis cancer has increased steadily from 1988-1991 and 2007-2011. Rates are more than five times higher among whites than blacks. Testicular cancer begins to rise in adolescence, peaks in the 20s and declines thereafter. While this disease is relatively easy to diagnose and treat, it sometimes results in death.
  • Thyroid cancer incidence rates are increasing, especially among women, and is highest among Filipinas and Vietnamese. While thyroid cancer is usually responsive to treatment, there can be long-term side effects.
  • Cervical cancer incidence is dropping with greater use of screening, which also reduces death from this disease. Vaccination and the HPV vaccine was approved in 2006 and is effective in reducing cervical cancer.
  • Uterine cancer has become more frequent with the highest rate found in Filipinas and the lowest in blacks.
  • Melanoma rates are highest among white women and men. More affluent AYAs tend to have higher rates of melanoma.

— Zen Vuong