Adult survivors of childhood cancer who were diagnosed in the 1990s are expected to live longer than those diagnosed in the 1970s, likely as a result of evolving treatment approaches, according to a new simulation study.
"Our study highlights both the success of efforts to reduce treatment-related late effects, as well as the challenges that remain to improve long-term survival in children diagnosed with cancer," Dr. Jennifer M. Yeh of Boston Children's Hospital told Reuters Health by email, noting that survivors "are still at risk for a shortened lifespan."
An earlier model-based study estimated that life expectancy was reduced by as much as 28% among survivors who originally received a diagnosis of childhood cancer between 1970 and 1986. The association of childhood cancer with life expectancy after more modern therapy, often chosen based on concerns over late toxic effects, remains unclear.
Dr. Yeh's team used data from the Childhood Cancer Survivor Study (CCSS) to develop a microsimulation model to estimate projections of long-term survival for childhood- and adolescent-cancer survivors diagnosed between 1970 and 1999.
Conditional life expectancy, the number of years of survival starting at five years from diagnosis, improved from 48.5 years for survivors who received a diagnosis in the 1970s to 53.7 years for those diagnosed in the 1980s and to 57.1 years for survivors diagnosed in the 1990s, representing significant increases.
During these three decades, the gap in life expectancy of survivors compared with the general population declined from 16.5 years (25%) to 12.3 years (19%) to 9.2 years (14%), the researchers report in JAMA Oncology.
The gap in life expectancy decreased by nearly half among survivors who had been treated only with chemotherapy, but there were only modest improvements in the gap in life expectancy among survivors treated with radiotherapy alone or with chemoradiotherapy.
Over this period, the gap in life expectancy remained stable for the subgroups that received no treatment or surgery alone.
Cumulative late recurrence and excess late mortality risk for secondary cancers, cardiac events, pulmonary and other causes decreased by treatment era.
Background mortality risk surpassed childhood cancer-related mortality risks at the age of 40 years among survivors who received no treatment or were treated with surgery only; at age 50 years for those treated with chemotherapy alone; and at age 60 years for those treated with chemoradiotherapy or radiotherapy alone.
"As secondary cancers and cardiac events are the leading causes of early mortality, adherence to follow-up care and risk-reduction behaviors can play an important role in improving life expectancy among survivors," said Dr. Yeh, also at Harvard Medical School. "This includes recommendations by the Children's Oncology Group which are available at www.survivorshipguidelines.org."
"Primary-care providers and oncologists who see these survivors should be sure to discuss follow-up care and risk-reduction behaviors, such as secondary breast-cancer screening, colorectal-cancer screening, and heart-disease assessments," she said.
"It is worth recalling that the CCSS includes data from patients diagnosed prior to 2000, before targeted biologic therapies or immunotherapies were widely available," Dr. Stephanie M. Smith of Stanford University School of Medicine, in Stanford, California, and colleagues write in an editorial.
"Radiotherapy has also evolved with the development of conformal approaches such as intensity-modulated radiation therapy and newer techniques such as proton therapy. Each of these new treatments is hypothesized to have fewer long-term and late adverse health effects compared with earlier approaches, but it is too early to be certain," they add.
"As pediatric oncology moves into the era of precision medicine to improve upfront survival rates, the future of late effects prevention in survivors of childhood cancer lies in genomic advances to detect susceptibility to treatment-related toxic effects," they conclude. "Although we have come a long way since the early days of pediatric oncology treatment, our work is far from complete."
SOURCE: https://bit.ly/2Qzw9jH and https://bit.ly/2Qx0Dma JAMA Oncology, online January 2, 2020.
Reuters Health Information © 2020
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