Extra months for cancer patients

Some patients with cancers which have spread to their bones could survive slightly longer with a new radiotherapy treatment.

While their lives are lengthened on average by a matter of a few months, this still represents a step forward for scientists because cancer is extremely hard to treat at this stage. Bone metastases are formed when tumour cells are present in large numbers in the bone marrow, and begin to grow there. Cancers that can form bone metastases in their later stages include common forms such as prostate and breast cancers. These growths can cause extreme pain for the patient, and often the aim of treatment is simply to relieve this, rather than try to extend life. Radiation deliveryHowever, a team of scientists from the University of Bonn in Germany have developed a new type of treatment which they believe targets bone metastases far more effectively. Prostate cancer patients given more than one dose of the treatment survived almost twice the length of time that doctors predicted. The treatment works by delivering a high dose of radiation to the tumour cells in the bone marrow. This is easier said than done – simply flooding the body with radiotherapy is impossible, so experts have to find a way to “deliver” their radiation directly to the cells they want. They do this by harnessing their radioactive molecule to a “disphosphanate”, a molecule which tends to accumulate naturally around prostate cancer cells. They used radioactive rhenium-188 which gives a powerful burst of beta radiation – but only over a few millimetres. The progress of their radioisotope was monitored using a camera sensitive to radioactivity. Months moreIn all, 64 patients were enrolled in their clinical trial, and one group given a single injection of the radioisotope, while the other had two injections. In the second group, the results were promising, and tests revealed clear signs that the cancer cells were under attack. Prostate cancer cells produce a chemical called PSA – and levels of this fell away as the treatment kicked in. Researcher Dr Holger Palmedo said: “In 39% the amount of the tumour marker PSA decreased by more than half – an effect that continued for at least eight weeks. “At the same time the survival of the patients to whom more than one injection was administered rose from seven to 13 months.” The treatment had few side-effects, and now the scientists plan to give three or more injections to see if the effect continues. (Source: BBC, Saturday, 9 August, 2003, 00:08 GMT 01:08 UK)