Kjell Dahl is a specialist physician at Stockholm South General Hospital. In his thesis, he presents 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.”
The 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.
Thesis: “Human colorectal cancer; Experimental staging and therapeutics”, Kjell Dahl, The Department of Clinical Research and Education, Stockholm South General Hospital, Karolinska Institutet