A treatment for an incurable blood cancer has been found to reduce by 45 per cent the chance of a relapse among patients who have gone into remission. The finding is the result of an international clinical survey of the effectiveness of an antibody-based treatment targeting patients suffering from follicular lymphoma. The treatment has been in use at Queen Mary Hospital in Pok Fu Lam since 2008. Professor Kwong Yok-Lam, of the hospital's haematology, oncology and bone marrow transplant department, said the survey confirmed the hospital's experience. Unlike chemotherapy, in which drugs kill the cancer cells, targeted therapy uses antibodies to prompt the immune system to attack the cells. It is mainly used in patients who have responded well to chemotherapy in a bid to keep them in remission. 'This is not a replacement for chemotherapy,' Kwong said. 'What people don't understand is that remission needs to be maintained. Targeted therapy is maintenance therapy.' Of the 90 people who are diagnosed with follicular lymphoma every year in Hong Kong, almost half will suffer a relapse within three years of their first-line treatment. At present, the direction of treatment offered by the Hospital Authority does nothing to combat this. Patients are given chemotherapy and then a wait-and-see policy is adopted; if a relapse occurs, then a second round of treatment begins. Rituximab, the drug used in targeted therapy, has previously been used in this type of treatment. 'This medication has been around for 12 years, it is not new,' Kwong said. 'Maintenance therapy is a new use of it.' He said the Hospital Authority was reluctant to use it in its institutions because of the cost - one injection cost HK$17,000 and maintenance therapy required an injection every three months for two years. A clinical survey of 1,217 patients by the Groupe d'Etudes de Lymphomes de L'Adulte in Lyon, France, found that 71.5 per cent of patients who received maintenance therapy for two years were in complete remission, compared with 52.2 per cent of those who did not receive the therapy. Kwong said he hoped the study's results would push the Hospital Authority to start using the treatment more readily. Targeted therapy also has fewer obvious side effects than chemotherapy has. An engineer who is undergoing the therapy while still working said the only side effect was 'that I feel tired for four to six days afterwards, like I have the flu'.