Despite cancer survival rates increasing dramatically for children and older adults in the last 20 years, there has been minimal improvement in the survival rates in the Adolescent and Young Adult (AYA) population, an age range defined as 15 – 29 years by the presenters. A lack of participation in clinical research trials, biological differences of the disease, limited resources of this age group, and fragmented treatment by pediatric and adult oncologists are some of the reasons for the lack of progress within this patient population according to physicians who recently presented an overview of AYA oncology at the NCCN 15th Annual Conference.
“Today, more than twice as many AYA patients than children under the age of 15 die of cancer. The dramatic progress made in the last three decades in curing children has not been seen in the AYA age group.”
“Cancer is the leading cause of death from disease in adolescents and young adults in the United States. Although 20,000 new cases are diagnosed each year — twice as many as in children under 15 — programs tailored to this population simply have not developed as they have for children,” noted Peter F. Coccia, MD of UNMC Eppley Cancer Center at The Nebraska Medical Center.
Dr. Coccia underscored the impact further stating, “Today, more than twice as many AYA patients than children under the age of 15 die of cancer. The dramatic progress made in the last three decades in curing children has not been seen in the AYA age group.”
“Traditionally, care of adolescent and young adult patients has been widely dispersed among pediatric and medical oncologists, which creates inconsistencies in treatment approaches,” echoed Nita Seibel, MD of the National Cancer Institute.
The large disparity of outcomes between children and the AYA population can be attributed to their lack of participation in clinical trials or not being referred to a cancer center to be offered a clinical trial or treatment approach with the best outcome.
Dr. Seibel explained that research shows that survival rates directly correlate with the level of participation in clinical trials and AYAs are the least likely group to participate in clinical trials. On the contrary, more than 90 percent of patients under the age of 15 years are managed by multidisciplinary teams using standardized treatment approaches in centers participating in the Children’s Oncology Group (COG) clinical trials.
“Older adolescent cancer patients have far less participation in clinical trials than younger patients due to a lack of knowledge of the specialized services available for these patients,” said Dr. Coccia.
Low participation rates in clinical trials are compounded by the lack of consistency in the approach to treatment in addition to scarcity of specific outcome data on AYAs noted the presenters.
In the age range of 15 – 29 years, some patients are treated by pediatric oncologists while others are managed by medical oncologists who traditionally have had different treatment approaches to their care.
However, research has shown that treating AYA patients with a “pediatric-directed approach” tends to lead to improved outcomes, most dramatically in patients with acute leukemia as well as bone and soft tissue sarcomas.
Dr. Seibel presented data from investigators in North America and Europe to support this concept using Acute Lymphoblastic Leukemia (ALL) to demonstrate the differences between pediatric and adult based treatment approaches. The improved outcome for AYA patients treated on pediatric regimens for ALL is probably in part related to a greater dose intensity of non-myelosuppressive drugs, earlier and more intensive central nervous system therapy, and a longer duration of maintenance therapy.
Another contributing factor to the lack of progress in AYA patients is the paucity of research into the genetic composition of cancers in this population. Little is known about potential differences in pharmacokinetic or pharmacogenomics regulation as patients get older as well as the impact of puberty and hormonal changes in this age group.
George D. Demetri, MD of Dana-Farber Cancer Institute spoke about the biological differences in solid tumor sarcomas between children, adolescents and young adults, and adults noting research demonstrating the unique gene expression of pediatric gastrointestinal stromal tumors (GIST).
“Data shows that pediatric GIST is a totally different disease biologically than adult GIST and needs to be managed accordingly,” said Dr. Demetri. “There needs to be a focus on defining the incidence of new molecular genetic prognostic markers in AYA patients as well as insights into drug toxicities, delays, and omissions in treatment for AYA patients to see more dramatic progress in the survival rates of this group.”
The presenters also touched upon the potential social challenges in the AYA population as each individual possesses varying degrees of independence.
“Whether patients are emancipated adolescents or still under parental supervision can have a huge impact particularly in compliance with oral medications,” stated Dr. Seibel.
The physicians concluded the presentation by stating that a focused effort to make sure patients are treated in centers where they will be offered either a clinical trial or treatment showing a high success rate along with a better understanding of the biology and clinical needs of this population will increase the likelihood of cure and enhance the quality of life.