Genetic test for cancer could result in reduced side effects from
treatment in children
2 April 2010
A genetic analysis technique that can identify a less
agressive form of a cancer could enable children to be given less
intensive treatment than current practice to reduce their risk of
damaging side-effects.
A collaboration between scientists at The Institute of Cancer
Research (ICR) in London and the Institut Curie in Paris has found a
genetic test that can identify patients with a less aggressive form
of the childhood cancer alveolar rhabdomyosarcoma. Rhabdomyosarcoma
is a cancer that resembles skeletal muscle and can arise in many
different locations in the body. The research was published in the
Journal of Clinical Oncology this week.
Patients with this less aggressive cancer may be receiving toxic
treatment they don’t need. Currently, treatment is based on whether
a patient’s cancer is classified as alveolar or embryonal, which is
determined by the appearance of a tumour sample under the
microscope.
Alveolar rhabdomyosarcoma is considered more aggressive, so these
patients are given a more intense combination of chemotherapy,
radiotherapy and sometimes surgery.
These treatments have helped improve rhabdomyosarcoma survival
rates, but also carry risk of serious and long-term side-effects
including the potential to develop another cancer later in life.
When the ICR scientists examined samples from 210 rhabdomyosarcoma
patients, they identified 39 cancers that looked like aggressive
alveolar type but behaved more like the milder embryonal type. This
group of patients had less cancer spread and higher survival rates.
Genetic testing revealed that the cancers from these patients lacked
a genetic abnormality, known as a PAX/FOX01 fusion gene, which has
previously been linked to the alveolar subtype.
ICR scientist Dr Janet Shipley says subsequent analysis of thousands
of genes confirmed alveolar rhabdomyosarcomas without a fusion gene
are biologically similar to the embryonal subtype but very different
from alveolar cancers with a fusion gene.
“We have shown that presence of a fusion gene — not tumour
appearance — is a key factor in predicting cancer aggressiveness,”
Dr Shipley says. “This study should lead to a re-think in the
management of children with the fusion gene-negative alveolar cancer
in order to minimise side-effects for these patients. There is no
longer any evidence to support treating all alveolar cases the
same.”
Dr Shipley says the next step is to hold a clinical trial to see if
reducing treatment intensity can improve these patients’ quality of
life while maintaining survival rates.
Lynn Lucas, whose son passed away in July 2000 after a three year
battle with rhabdomyosarcoma, says the treatment left Chris with
serious side-effects including weight loss, difficulty walking and a
painful mouth.
“We saw first-hand the horrific side-effects of the treatment for
this disease. We will be very pleased if this research leads to some
children diagnosed with alveolar rhabdomyosarcoma not suffering in
the same way,” Mrs Lucas says.
The research was funded by Chris Lucas Trust, Cancer Research UK, La
Ligue Nationale Contre le Cancer, Institut National du Cancer and
Enfants et Sante Association.