Friday, April 15, 2011


You all may remember that in June 2010, I reported on a meta-analysis by the now world famous Dr Sipahi, which showed that the use of ARB may be assocaited with an increase cancer risk, especially lung cancers. This prompted the FDA and European EMA to look into this issue before deciding on the long term safety of ARBs.
Well this month of April, saw tow studies, trying to answer this question. One is a Dutch observational study and the other is another meta-analysis.
The Dutch observational study was reported in the April 11 issue of Circulation. It was led by Dr Bjorn Pasternak. The researchers looked into the records ob more then 300,000 patients. 107,466 were on ARBs and 209,692 were on ACE-I, for hypertension. At the end of 3 years of follow up, they found no increase incidence of cancers among those who were on ARBs.
The second study was a meta-analysis, called the ARB trialist collaboration. They looked at 15 RCT, involving about 140,000 patients, comparing the use of ARBs, with comparable medications, including ACE-I, CCBs etc. After 5 years follow-up, they also also concluded that there was no increase in cancer rates among ARB users. The authors also mentioned, in particular that there was also no increase in cancer risks amongst those who were taking ARB+ACE-I.
This last statement was put in, because a Nov 2010 meta-analysis, led by the hypertension expert, Dr Frank Messerli, seemed to suggest that although there was no increase in cancer risk amongst ARB users, his meta-analysis reported in Nov 2010, seemed to suggest that there was an increase risk amongst those taking ARB + ACE-I.
Whenever these kinds of statements are made at the end of an expert's statement, it always leave a slightly bitter taste, leaving one to wonder, whether there was or there was not. Afterall, ARB+ACE-I, is like a very powerful ARB. Then the worries go on.
Well, at the moment, the score seems to be 3-1 in favour of ARBs having no increase risk of cancers, or to put it more crudely, it is Sipahi versus the rest. say what you like, we should in a way thank Dr Sipahi, and group for bringing up the potential issue. It has certainly generated more work for researchers. Unfortunately, it may have scared off some potential ARB users as well.
Personally, looking at all the evidence, I would think that in those who are susceptible to cancers, ARBs and ARB+ACE-I should be used with caution. The complex physiological reactions that the powerful ARBs can trigger, may provoke cancers ( in those who are somewhat susceptible. I have always wonder why researchers did not look into the issues of ARB use, in those who have survived Ca Lungs, or Ca Prostates, and see their outcome after 5-10 years.
I am also concerned that all our meta-analysis and follow-up, may not be long enough. This was one of the concerns raised after Dr Sipahi's paper in June 2010. Maybe, with longer follow-up, the findings may be different, especially in those proned to cancers.
Well, for now, the score is 3-1, but I am sure, the debate will go on. Exercising caution and close monitoring of patients on ARBs should continue, and also a close watch on the literature, as we are doing.

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