Possible pills for cancer - and how they work


The figure for cure rates for cancer in adults has improved year on year for the last 14 years.  On average 5,000 fewer people have been dying of cancer each year since 1990.  There has been a 12-14% increase in cure rates in breast cancer whilst children's cancer treatment is increasingly successful.

Breakthrough treatments have been in rare cancers such as testicular cancer, childhood leukaemia, Hodgkin's disease and lymphoma.  But cancer researchers anticipate that within 10 to 15 years new drugs, based on molecular biology, should be available that will tackle all the big cancers - lung, breast, colon and prostate.

Cell killing
One promising line of research is into ADEPT, an acronym for antibody-directed enzyme pro-drug therapy.  This is a two stage therapy.  In the first stage, the patient is injected with antibodies which have the characteristic that they bind onto cancer cells.  The antibodies have an enzyme attached to them as it were piggy backed on the antibody.  A few days later comes stage two, in which the patient is injected with a toxic cancer drug.  This toxic drug is activated by the enzyme which is already on the cancer cells but not attached to healthy cells.  The idea is that the cancer cells are killed in a matter of minutes leaving the healthy cells alone.  ADEPT has been worked on for the past eleven years and clinical studies have just started at the Royal Free Hospital, London.

Starvation
Another line of research about which many experts are enthusiastic is vascular targeting.  Tumour cells like other cells cannot multiply without a blood supply.  In aggressive tumours blood vessels grow rapidly and chaotically.  Now, drugs have been developed which aim to cut off the blood supply to tumours, causing vascular shutdown and so shrinking them to a manageable size.

Gene therapy
Destroying cancer cells through gene therapy is yet another promising approach.  Dr Ros Eeles and Dr David Dearnaley, at the Institute of Cancer Research in Surrey have undertaken a nationwide search for prostate cancer genes.  The project will be examining the DNA of large numbers of men.  To deal with the volume of results, Prostate Research Campaign UK has helped finance a new gene sequencer which can analyse DNA samples 36 times faster than earlier equipment.

The team at the Sutton based institute has already been responsible for discovering an important breast cancer gene, BRCA2.  For prostate cancer Dr Eeles is looking for two kinds of gene - a high risk gene which is likely to show up from the study of families with a history of prostate cancer and a low risk gene which is likely to be more prevalent in the general population.  If the genes are found, it opens up the prospect of screening to detect those at high risk..