A range of drugs widely used to treat high blood pressure and heart failure may be linked to cancer, a new study suggest.
Use of angiotensin receptor blockers (ARB) was associated with a "modestly increased risk" of new cancer diagnosis, said researchers.
Although the likelihood of developing cancer while taking one of the drugs was small, one expert called the findings "disturbing and provocative".
Others urged patients on the potentially life-saving drugs not to stop taking their medications. ARBs are commonly prescribed for the treatment of high blood pressure, heart failure, and kidney damage due to diabetes.
They work by blocking the activity of a hormone that prevents blood vessels from dilating, thus raising blood pressure.
Although the drugs are considered safe, one previous trial reported a significant increase in fatal cancers in patients treated with the ARB candesartan.
To carry out the new investigation, US researchers pooled together and analysed all the previously published data from ARB studies prior to November 2009.
They also looked at new data from five trials involving 61,590 patients, and trends relating to lung, prostate and breast cancers, and cancer deaths. Part of the analysis involved deaths among 93,515 patients who took part in eight trials. More than 85pc of the patients were taking one type of ARB, telmisartan.
The findings showed that 7.2pc of patients taking ARBs were diagnosed with a new cancer over a period of four years compared with 6pc of patients not treated with the drugs.
Although the result was significant, the authors led by Dr Ilke Sipahi, of Cleveland, Ohio, stressed that it should be seen in context.
Among specific solid organ cancers examined, only the risk of lung cancer was significantly increased in patients taking ARBs. Their risk was raised from 0.7pc to 0.9pc.