A new approach to treating advanced anal cancer is safer and more effective than the most widely used current treatment, a study has found.
Because of the small number of patients, there is very limited evidence to guide treatment decisions, but researchers said the findings from their study will set a new standard of care for this rare type of cancer.
The international phase II trial, led by the Royal Marsden NHS Foundation Trust, analysed data from 91 patients in four countries, including the UK, Norway, the US and Australia, and found that patients with advanced anal cancer lived seven months longer overall.
The team found that a chemotherapy combination of carboplatin and paclitaxel - which is primarily used to treat other cancers, including ovarian, womb and lung cancer - performed better overall compared to chemotherapy treatment with cisplatin and 5-fluorouracil.
In the trial, endorsed by the International Rare Cancer Initiative (IRCI), carboplatin and paclitaxel performed better both in terms of survival rates and safety.
Until now, when anal cancer had spread or come back after treatment, doctors had considered cisplatin and 5-fluorouracil to be the preferred first-line treatment option.
The findings are being presented at the European Society for Medical Oncology (ESMO) Congress in Munich, Germany.
Study chief investigator Dr Sheela Rao, consultant medical oncologist at the Royal Marsden, said: "The results of this study will immediately change patient care.
"While treatment with cisplatin and 5-fluorouracil was generally considered a reasonable option for advanced anal cancer, we now know that carboplatin and paclitaxel is more effective and better tolerated.
"In our study, these patients lived seven months longer overall.
"Around 30 per cent of people with anal cancer will develop advanced disease which cannot be treated surgically, and all of these patients are eligible to receive this chemotherapy combination."
Study co-author, professor David Sebag-Montefiore, an anal cancer expert for Cancer Research UK, said: "Making progress in rare cancers is incredibly difficult, so it's very exciting to see these results which, in my opinion, are practice changing.
"This important research informs both patients and their cancer teams that the combination of the chemotherapy drugs carboplatin and paclitaxel should be first line treatment for advanced anal cancer.
"This study also shows the benefit of international collaboration within the IRCI - it can deliver results in rare diseases that individual countries cannot achieve on their own."
Professor David Cunningham, director of the NIHR Biomedical Research Centre at the Royal Marsden and the Institute of Cancer Research, London, said: "These findings set a new standard of care and highlight the importance of international collaboration for advances in the treatment of rare cancers.
"We now have the backbone for future trials into novel treatments for advanced anal cancer, including immunotherapy."
