In a breakthrough that could revolutionise the treatment of cancer, a new gel treatment for breast cancer is being developed and tested in the US to shrink tumours. The treatment is rubbed on to the skin daily and has far fewer unpleasant side effects than the tablet tamoxifen – the most commonly used drug in Britain. But it contains the same active ingredient, and concentrates it in the breast rather than dispersing it around the entire body like pills do. \"We think it may be a very good solution for women who are reluctant to take tamoxifen,\" the Daily Mail quoted researcher Professor Seema Khan, of Northwestern University near Chicago who is testing the gel, as saying.