Scientists recently discovered that improved cancer treatment approaches over time correlate with higher life expectancy in adult survivors of childhood cancer.
As cancer treatment evolves to be more effective, more patients are surviving, with some even living long lives disease free. In order to determine if life expectancy also rises with evolving treatment, the investigators examined data derived from the Childhood Cancer Survivor Study, which included data on 5-year survivors of childhood cancer who were diagnosed between 1970 and 1999. Information was analyzed using a microsimulation model comprised of competing mortality risks. The model included data on late recurrence, treatment-related late effects, and US background mortality rates. The population subgroups included those who received no treatment or surgery only, chemotherapy alone, radiotherapy alone, or radiotherapy with chemotherapy. The researchers also separated the study population by the era in which they were diagnosed with cancer (1970-1979; 1980-1989; and 1990-1999).
The results, which were published in JAMA Oncology, revealed that conditional life expectancy (defined as the number of years a 5-year survivor can expect to live) was 48.5 years for 5-year survivors diagnosed in 1970-1979, 53.7 years for those diagnosed in 1980-1989, and 57.1 years for those diagnosed in 1990-1999. The gap in life expectancy compared to individuals with no history of cancer was 25% in those diagnosed in 1970-1979, 19% for those diagnosed in 1980-1989, and 14% for those diagnosed in 1990-1999.
The percentage of survivors who were treated with chemotherapy only increased during the three decades from 18% in 1970-1979 to 54% in 1990-1999; in addition, the life expectancy gap decreased from 11 years to 6 years for this group. The patients treated with radiotherapy or radiotherapy plus chemotherapy only experienced a marginal improvement in the gap in life expectancy in survivors versus individuals with no history of cancer. For patients who survived acute lymphoblastic leukemia, the gap in life expectancy decreased from 14.7 years to 8.0 years during the three decades.
"Evolving treatment approaches are projected to be associated with improved life expectancy after treatment for pediatric cancer, in particular among those who received chemotherapy alone for their childhood cancer diagnosis," conclude the study authors, led by Jennifer M. Yeh, PhD, Associate Scientific Researcher and Assistant Professor of Pediatrics at Harvard Medical School. "Despite improvements, survivors remain at risk for shorter lifespans, especially when radiotherapy was included as part of their childhood cancer treatment."
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