30 June 2011

Unhealthful News 181 - Avastin likely to be de-listed for treating breast cancer; if only they explained why

This week there was some seriously unhelpful health news.  One of the most talked about bits of health news of the last few days (example, example) is that an FDA committee concluded that the drug Avastin used to treat several types of cancer, is a bad choice for treating breast cancer.  It is likely that the FDA will therefore withdrawal approval for that use.

I was curious about what was known, what the concerns were, what motivated the decision, what will happen, etc., so read some of the news and health pundit reports on the topic.  I could have kept going, and probably pursued a more technical angle, but I started to find it more interesting to realize that I was learning almost nothing from what I was reading that was not contained in the headline. 

The committee's unanimous judgment was that the risk outweighed the benefits.  The only counter-arguments discussed were breast cancer patients who believe they have benefited from the drug begging not to lose it.  Today it was announced that Medicare would still cover its use for breast cancer (because it will still be approved for other cancers, it will be on the market and FDA regulations do not prevent it from being used "off label").  This brings up some questions.

"Risks outweigh the benefits" can have rather different meanings.  One of them is the subtle "if you use this drug rather than another then, adding up all the outcomes including cures and side effects, you are a bit worse off."  That is a case where nothing much can be done except look at the overall statistics and go with them.  But there are other variations, an extreme version of which might be, "this drug saves 5% more of those who take it for a year compared to the alternative, but it rapidly kills 6% of those who take it."  There is no practical difference among these unless it is possible to figure out if someone is in the group that benefits or suffers from the choice, and presumably that has already been done based on demographics and details of the cancer to the extent currently possible. 

There is one other possibility, where it is possible to start a treatment and figure out whether it is going well.  I have no idea whether that might be possible in this case.  You would think that after reading thousands of words analyzing the regulatory decision some information might have creeped in, but no.  Some of the severe side effects mentioned (digestive system perforations, bleeding) are such that they can be detected and perhaps treatment can be changed, but perhaps it is then too late or changing the treatment is not safe.  I am sure these are known, but no on reported them. 

Some pundits complained that the news stories took many paragraphs to get to the most important point, that the studies show that the drug does not improve survival.  I agree that this is the most important point.  But I take issue with the implication that this is all that is useful to know.  There is talk about continued research to find if there is a subset of breast cancer victims who might benefit; that is what pharma companies always want to do in cases like this.  But it might be possible to identify cases that are benefiting.  Or it might not.  The news and pundits appear to be utterly silent on that point.

This is interesting because of the amount of attention devoted to women who were asking that the drug not be taken away from them because they believed it was helping.  Not a single report or analysis I saw argued made the obvious point, that they have no way to know that because they have no idea what would be happening if they were not taking the drug.  (There is evidence that the drug slows cancer growth even while not improving longevity, which would create the appearance of benefit.)  On the other hand, no one suggested it might be the case that this subset is right about them being the ones who benefit (which would mean that others have been hurt because we know the balance is "no benefit").  Perhaps it is the case that if someone escapes the nasty obvious side effects then having the drug is better than not having it.  That is kind of like the 5%/6% scenario I made up, wherein if it does not kill you early it is helping you.  Presumably this information exists, but the allusions in the news to there being some slight prognosis improvements for some stages of cancer were not very useful.

This brings up a second question, which is why anyone expert would suggest continued use is a good idea.  Individual consumers are often irrational, and mistakenly think that averages do not apply to them, and think they can see causation (that the drug is causing them to be healthier) when it is really too complicated to see.  Individual medics are no better.  But Medicare's policy decision implies that someone who is supposed to understand these things thinks it is wise to keep using Avastin to treat breast cancer.  Yet to the news reader, there seems to be no basis for expert disagreement in the discussion.  If there is no benefit, then there is no benefit.  Again, presumably I could dig deeper into expert discussions and make sense of this, but how can it be that the news reports implicitly tell us there is this controversy, but no one thinks to report the basis of disagreement?

The only consternation reported was not about the challenge of scientific disagreement, but what to do with all of those poor women who are benefiting from the drug and testified in favor of keeping the indication.  (Answer: Um, let them keep taking it if they really want it so much?  It is not being banned after all.)  The committee hearing was even called a "death trial" for them (as in "death panel"), because they were not just statistics.  Some local news stories picked up individual examples of the human interest drama of those who will be deprived of this wonderful drug.  Oh, where to start.

We expect superficial news reporting that emphasizes uninformative stories over useful statistics.  In is pretty typical that the useful statistics are buried in the article.  But in this case, nothing that was reported allows the reader to have any idea if the anecdotal claims have any basis, or should have any effect on decision making.  There is the usual spate of statements like "the plural of anecdote is not data" from self-styled pundits, but that statement is not actually true.  There are plenty of situations where anecdotes about the non-average cases are informative.  There are cases where off-label use of makes sense for an identifiable subset, and so Medicare should pay for it.  Is this one of those cases.  Maybe someone understands these points and knows the answers, but they are apparently not among those writing the news and commentary.

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