18 January 2015
People who develop cancer during childhood are much likelier to live longer lives in the modern day due to the availability of improved therapy options.
This is according to a new study from St Jude Children's Research Hospital in the US, which has shown how the evolution of medical technology and scientific understanding in the last few decades is helping more and more childhood cancer survivors to enjoy better life expectancies than was ever possible in the past.
Published in the New England Journal of Medicine, the research examined 34,033 childhood cancer survivors whose cancers were diagnosed and treated between 1970 and 1999 when they were aged 20 or younger. All the patients in this group lived at least five years after their cancers were discovered and were therefore considered long-term survivors.
It was shown that the 15-year death rate among survivors has decreased steadily since 1970, dropping from 12.4 per cent in 1970-74 to six per cent in 1990-94. During the same period, deaths from the late effects of treatment also decreased from 3.5 per cent to 2.1 per cent, with a drop in death rates from secondary cancers and lung or heart problems cited as the reason for this.
Patients diagnosed with standard-risk acute lymphoblastic leukaemia (ALL), Hodgkin lymphoma or Wilms tumour as their primary cancer during childhood were shown to have benefited most prominently, with five-year survival rates for these groups now estimated at 90 per cent or better.
It was explained that these improvements can largely be attributed to changes in paediatric cancer therapy and follow-up care, including reductions in the use and dose of radiation therapy and chemotherapy drugs called anthracyclines, which can put patients at increased risk of developing subsequent cancers, heart failure or other serious health problems.
Between the 1970s and the 1990s, the percentage of ALL survivors involved in the research who were treated with potentially harmful brain irradiation techniques decreased from 86 per cent to 22 per cent, with St Jude publishing evidence in 2009 that paediatric ALL is curable without brain irradiation, leading the hospital to phase the technique out entirely.
Additionally, it was shown that the percentage of Hodgkin lymphoma patients treated with radiation fell from 96 per cent to 77 per cent over the same period, while for Wilms tumour the rate dropped from 77 per cent to 49 per cent. During the same period, the average cumulative anthracycline dose also declined.
Study principal investigator Dr Greg Armstrong, an associate member of the department of epidemiology and cancer control at St Jude Children's Research Hospital, said: "This study is the first to show that younger survivors from more recent treatment eras are less likely to die from the late effects of cancer treatment and more likely to enjoy longer lives.
"The results are a testament to the physicians and scientists who in the past 30 years took a calculated risk of developing new protocols that used less intense therapies that reduced the risk of late effects and maintained excellent five-year survival."
Posted by Jeanette Royston
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