Treating colorectal cancer with lymphocytes is alternative to
13 May 2007
Researchers at Karolinska Institutet in Sweden have
discovered a new method of treating advanced colorectal cancer without the
need for chemotherapy. By removing special lymphocytes (white blood cells),
cultivating them and returning them to the patient s body, scientists can
strengthen the patient's immune defence and stop the spread of the tumour.
Kjell Dahl, a specialist physician at Stockholm South General Hospital, has
written his thesis on immunotherapy as an alternative to chemotherapy
(cytotoxins and cytostatics) for the treatment of advanced colorectal
cancer. The method has no adverse effects and may save and prolong the lives
of seriously ill patients.
Cancer tumours in the large bowel spread into
the body through the lymphatic system, passing into the lymph nodes via the
lymphatic vessels. The first lymph node passed is commonly called the
sentinel node, from where the lymph spreads in different directions around
the body. The sentinel node is therefore a good indicator of whether or not
the cancer has spread. The lymph nodes contain lymphocytes, which form part
of the body's immune defence. Different lymphocytes react with and kill
different intruders that invade the body.
The scientists have managed to
identify the sentinel nodes during surgery and have found the lymphocytes
that attack cancer tumours in the large bowel. They have also succeeded in
isolating the lymphocytes and cultivating them in vitro, and then returning
them to patients via blood transfusions. This procedure, which strengthens
their immune defence, is called immunotherapy and has no adverse effects
since it uses the body's own material.
"Patients treated with this method
fared better than those treated in the conventional way," says Dr Dahl. "In
some patients, the tumour was completely eradicated. The average lifespan of
patients with serious forms of advanced colorectal cancer was prolonged from
less than a year to, on average, just over two and a half years."
scientists have also discovered that it is possible to identify the first
draining lymph node of the daughter tumours of a tumour (metastases), and
that these nodes also contain tumour-reactive lymphocytes. These nodes are
called metinel nodes and they too can be isolated and cultivated in vitro
before being returned into the patient's body.
Dr Dahl stresses that the
study has its limitations, but also that the indications are good. A more
broad-based trial is now being planned in a multi-centre study to be run by
SentoClone, a company specialising in immunotherapy.
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