Improvements in treatments and outcomes for teenagers and young adults (TYAs) with cancer are being held back by faltering recruitment rates for clinical trials, new UK data suggest.

According to Dr Lorna Fern of University College Hospital in London, the recruitment gap is particularly pronounced in 15-24 year-olds, with an average of 16.6% joining clinical trials for cancer between April 2005 and March 2008, compared with 44.1% of 5-14 year-olds over the same period.

Dr Fern is research and development co-ordinator for the National Cancer Research Institute’s Teenagers and Young Adult Clinical Studies Development Group. Addressing Teenage Cancer Trust’s Fifth International Conference on Teenage and Adult Cancer Medicine this week, she presented the results of an analysis of 23 trials involving 4,429 cancer patients aged 0-59 years who were recruited in England, Scotland and Wales between April 2005 and March 2008.

Dr Fern found considerable variations from one cancer type or year to another in the proportion of newly diagnosed patients entering clinical trials. Some cancers had particularly poor accrual rates. For example, up until 2006/07 no young people over the age of 16 years had been recruited to treatment trials for brain tumours in England, despite four trials having been open during the study period.

However, new data for 2007/08 showed that two patients in this age range had entered trials for brain tumours during the past year. Brain tumours are one of the most common cancers that prove fatal in young people, with the incidence of some types reported to be on the rise.

In terms of age groups, Dr Fern’s data revealed that accrual rates for patients aged 20-24 years dropped substantially between April 2005 and March 2008.

Specifically, in 2005/06 42.6% of 10-14 year-olds with cancer were recruited to clinical trials compared with 22.9% of 15-19 year-olds and 13.4% of 20-24 year-olds. In 2006/07 there were slight increases in accrual rates for 15-19 year-olds (down to 41.3% for the 10-14 year-old group but up to 27.3% for 15-19 year-olds) while the proportion of 20-24 year-olds recruited to cancer trials fell to 10.9%.

Dr Fern was concerned these trends would continue, as the 2007/08 data suggested recruitment of 20-24 year-olds had dropped to around 7.5% compared with 39.7% of 10-14 year-olds and 25.4% of 15-19 year-olds.

Among the reasons for the low level of recruitment among TYAs with cancer were inappropriate study design and poor accessibility to trials, she said. Moreover, not enough young people were being treated by specialist cancer teams.

"At present, the design and age eligibility criteria for trials tend to reflect whether the trial organisers treat children or adult patients, rather than the biology of the particular cancer, and the age group which it is mostly likely to occur in,” Dr Fern commented. “Traditionally, trials will have an age cut-off between 16 and 20. TYAs are constantly falling through the gap created by the tendency for paediatricians to treat the younger ages, and for the older ages to be treated in adult cancer wards.”

The higher proportion of 10-14 year-olds entering cancer trials was partly explained by the tendency to treat this population in specialised paediatric units, which in the UK run Children’s Cancer and Leukaemia Group (CCLG) trials, Dr Fern added. There was no such co-ordinated body for TYAs aged 17-24 years, who “will most likely be treated in an adult ward and so access to CCLG trials is limited or non-existent”.

If advances were to be made in the treatments and outcomes for TYAs with cancer, “there needs to be closer dialogue between research groups when they are planning cancer trials”, Dr Fern warned. “They should give particular consideration to the specific needs of this over-looked age group so that a more appropriate trial portfolio for TYAs can be established in the UK.”