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 Looking at 60 years of data on nearly 35,000 childhood cancer
survivors, researchers found decreasing mortality rates overall, and
fewer deaths from cancer itself or from after-effects of cancer
treatment. By the time survivors are in their 60s, circulatory
problems like cardiovascular disease are their biggest cause of
death – just like the rest of the population.
“Survival after almost all specific types of childhood cancer has
improved substantially,” said lead author Miranda Fidler of the
Center for Childhood Cancer Survivor Studies at the University of
Birmingham.
The improvements align with new developments such as chemotherapy,
introduced around 1970, and bone marrow transplants, developed
around 1990, both of which are life-saving, Fidler told Reuters
Health.
To investigate long-term health outcomes for childhood cancer
survivors, the researchers analyzed data on 34,489 survivors of
childhood cancer diagnosed between 1940 and 2006.
Using death information from national registries, the researchers
determined how long patients survived and what eventually caused
their death.
Overall, 4,475 subjects, or 13 percent, died, representing a
mortality rate more than nine times that of the general population.
Researchers calculated the proportion of excess deaths – those
beyond what would be expected in the general population – for the
childhood cancer patients overall and looked at death rates and
causes by age group.
Overall, 66 percent of excess deaths were from a return or
progression of the original cancer, 17 percent were due to a new
cancer and 5.6 percent of the excess deaths were attributed to
circulatory conditions such as heart disease and high blood
pressure.
The number of excess deaths was much lower among those treated more
recently for childhood cancer. For example, there were 70 percent
fewer excess deaths among survivors treated between 1990 and 2006
than among those treated before 1970. Patients treated after 1990
also had 70 percent fewer deaths from recurrence or progression of
their original cancer, according to the results in The BMJ.
The longer people lived, the less likely their deaths would be
linked to their original cancer or to a new one. Among cancer
survivors in their 50s, 41 percent of excess deaths were caused by
new cancers and 22 percent by circulatory conditions.
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After age 60, 31 percent of excess deaths were caused by new cancers
compared with 37 percent caused by circulatory issues.
This is the first study to observe this shift to where the greatest
risks to a group of childhood cancer survivors are circulatory
diseases, the study team writes.
Still, the extra circulatory deaths may be due to organ damage
children suffered during radiotherapy and chemotherapy, said Mary
McBride of the British Columbia Cancer Agency in Vancouver, who was
not involved in the study.
“Newer and more complex treatments have led to higher likelihood of
survival from cancer in children and adults, but sometimes at the
cost of damaging complications,” McBride said by email.
These effects can be mitigated, however, she told Reuters Health.
“With appropriate follow-up care, these complications can sometimes
be prevented or managed to reduce the harmful side-effects of these
life-saving treatments and improve survivor quality of life.”
Both doctors and patients should be aware of the risks of developing
circulatory conditions later in life, and long-term follow-up
programs should aim to prevent these issues through education and
interventions, Fidler said.
SOURCE: bit.ly/2cdmpXL The BMJ, Online September 1, 2016.
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