By Michael Smith, North American Correspondent, MedPage Today
Increasing access to clinical trials in the U.K. was paralleled by a sharp rise in childhood cancer survival, researchers reported.
In 1966 through 1970, 5-year survival for all types of childhood cancers was just 28%, according to Charles Stiller, MSc, of the University of Oxford, and colleagues, but by 2005, the 5-year survival was 78%.
And survival increased significantly from 1978 through 2005 for every diagnostic category, Stiller and colleagues reported online in Annals of Oncology.
The increases took place after the 1997 establishment of the U.K. Children’s Cancer Study Group. During this period, two-thirds of children diagnosed with cancer in Britain had a cancer type for which there was an open national or international clinical trial, Stiller and colleagues noted.
The “improvements in childhood cancer survival match those reported by the relevant clinical trials that were running between 1978 and 2005,” Stiller said in a statement.
“Although trends in childhood cancer survival have been reported in relation to improvements in treatment in the U.K. and elsewhere,” Stiller said, “this is the first time that population-based survival has been examined in relation to the clinical trials open to entry at the time.”
Inclusion in clinical trials is usually regarded as best practice for children with cancer, the researchers noted, but the impact of that on population-based survival has only rarely been studied.
To help fill the gap, they studied outcomes for 25,853 children, diagnosed in Britain from 1978 through 2005, with diseases for which there was a multicenter trial of first-line treatment, which was open to entry during at least 10 years within the study period.
The children in the analysis — diagnosed with conditions ranging from acute lymphoblastic leukemia to Wilms tumor — represented 66% of all childhood cancers diagnosed in England, Scotland, and Wales during the study period.
Participation in trials has increased steadily, the researchers reported, with up to 90% of children with many cancer types enrolled in recent years.
The analysis showed that for each diagnostic category, there was an annual reduction in the risk of death, ranging from 2.7% a year for rhabdomyosarcoma to 12% a year for germ cell tumors of the testes and ovaries.
However, trends were not universally steady, the researchers noted.
For example, in children ages 1 through 14 with acute lymphoblastic leukemia, 5-year survival was 49% in 1978, but rose steadily to 90% at the end of the study period. On the other hand, in neuroblastoma in the same age group, there was no consistent trend in survival before 1990 but a clear increase after that, reaching about 50% by 2002.
And for several other cancer types, including Ewing’s sarcoma of bone, 5-year survival increased until the mid-1980s but has not improved much since then.
The researchers noted that changes in adult care can take several years to diffuse into general oncology practice, but “in this study of a wide range of childhood cancers, the most dramatic increases in survival occurred much more immediately.”
That’s not surprising, they argued, given the large number of children enrolled in trials. Also, even non-trial patients would mostly have been treated at the same pediatric oncology centers, using the standard arm of the current trial as best practice, they wrote.
The investigators noted that as diagnostic techniques improved over time, patients may received an earlier and more accurate diagnosis, which also may have improved survival.
The study had support from the Department of Health, the Scottish Government and CHILDREN with CANCER UK.
The authors declared no conflicts of interest.
Primary source: Annals of Oncology
Source reference:
Stiller CA, et al “Population survival from childhood cancer in Britain during 1978-2005 by eras of entry to clinical trials” Ann Oncol 2012; DOI: 10.1093/annonc/mds183.
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Michael Smith
North American Correspondent
North American Correspondent for MedPage Today, is a three-time winner of the Science and Society Journalism Award of the Canadian Science Writers' Association. After working for newspapers in several parts of Canada, he was the science writer for the Toronto Star before becoming a freelancer in 1994. His byline has appeared in New Scientist, Science, the Globe and Mail, United Press International, Toronto Life, Canadian Business, the Toronto Star, Marketing Computers, and many others. He is based in Toronto, and when not transforming dense science into compelling prose he can usually be found sailing.
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