Last week's news about Herceptin made quite a splash, and there are several reasons for that. The main one is the correct one: this is good news for breast cancer patients, and a real advance in the treatment of the disease. The other reasons for all the excitement may not be quite as justifiable, though. In short, while this is significant, it's a long way from a cure.
Herceptin (trastuzumab) is an antibody targeted to a growth factor receptor called HER2 (more background from a previous post here, and from Genentech here. Those are the short version and the long version, more or less). If the cancer doesn't express HER2, it will not respond to Herceptin. The more dependent the tumor is on HER2 for its growth, the better the antibody will work, which is a common theme among cancer therapies. (An extreme version is found with Iressa, where if the tumor doesn't have the rare mutation that makes it dependent on the drug's targets, it doesn't work at all).
So, how many breast cancers express HER2? There are several ways to assay that, and the numbers disagree a bit, but a bit under 20% seems like a reasonable answer. Put more harshly, for about 80% of breast cancer patients, herceptin is of little or no use. This has been proven quite thoroughly, but it's going to be hard to explain to patients who are newly diagnosed and want to know where that cure is that they've read about.
I haven't seen any headlines that have tried to explain that these results are good news for only a certain group of breast cancer sufferers. Many of the press reports get around to mentioning this eventually, although rarely in the first paragraphs - you wonder how many people are still reading when they get to the fine print. The fine print, in this case, would include the numbers that show a twelve per cent increase in disease-free survival after three years. That's big news in oncology, but isn't generally the kind of number that you makes you throw around the word "cure". I hope that some of the people in these news stories have been quoted out of context.
It's true that by the time you add up the taxanes, the estrogen receptor ligands like Tamoxifen, the aromatase inhibitors, and the general advances in surgery and early detection, that breast cancer is a less fearsome disease than it was five (or ten, or twenty) years ago. But advances in this area get overhyped because - and I hate to bring this up - the disease itself is overhyped. Don't get me wrong - it's bad. But it's far from the worst.
The rate of breast cancer, like many other cancers, appears to be declining (PDF), measured both by incidence and by death rate. It's well behind that of lung cancer in the female population, which moved into first place nearly 20 years ago (see the graph on page 5 of this PDF), but it gets easily ten times the press, and surely generates ten times as much worry. Lungs, though, are not visible manifestations of femininity, and come with no cultural or political meaning attached. I'm sure that there's a ribbon color for lung cancer, although I don't know what it is, and I don't know when their Awareness Month might be. This is especially odd when you consider that most of the high incidence of lung cancer is from a completely avoidable cause. . .
(I see that Medpundit has a very similar take on this: "Don't sell the house" is her advice.)
1. otey on October 25, 2005 8:10 AM writes...
Just a note to say thanks. These are the kind of entries that keep laymen like me visiting your blog daily. Informative, well written pieces that only you seem to be able to do.
Permalink to Comment2. Still Scared of Dinosaurs on October 25, 2005 9:48 AM writes...
I notice that the ACS document mentions that herceptin only works in HER2/neu+ cancers when describing the drug, but does not mention HER2 in its section about factors that affect survival in br ca patients. I think this might be related to HER2+ cancers being more aggressive so that herceptin levels the playing field(??). If this is true then even that bit of information might be useful to HER2- women who want to ask about "that miracle treatment I heard about from my cousin".
What I think really frustrates a lot of patients is the experience of gathering information piecemeal and wondering what the relevance to their case is. The ACS brochure could be a start, but what would really be useful would be a companion "scorecard" where the information for a given patient could be entered and the relevant pages of the document could be given. Even when it adds up to pretty bad news at least that's real news that can be used to inform treatment and lifestyle decisions.
Permalink to Comment3. Dr Snowboard on October 25, 2005 11:20 AM writes...
Burke the whole vitamin "splash" runs as a clear tactic of complementary quackery for the past 15+ years as a method of maintaining a positive perception of a lucrative direct selling industry. A report about an unsubstantiated research finding gives the general gullible public hope that a miracle "cure" is just around the corner. Which creates the phony impression that vitamin companies are aggressively seeking to fund and find cures when selling treatments is the proper word here. That their motivating factor is the good of mankind, when in fact as a publicly traded company their primary concern is profit.
When you dig beneath the surface Burke and your vision is not clouded by the dollars deposited in your bank account by the perpetrators of deception and carnage to mankind (a more accurate description of vitamin direct sellers) you begin to see clearly that the main reason vitamin peddlers are among the leading advertisers and pushers of unsubstantiated news stories (which are in fact advertisement under the guise of science) is that without it they would lose their tenous grip on the gullible uninformed market, which is their Golden Goose.
Doubters just watch, before long you'll have another news story about a cure for diabetes or cancer or heart disease of even HIV/AIDS that is 'natural' and completely safe - so predictable it is pathetic. But the sheep know their shepherd and respond - Thank God I'm not a member of that flock. Others would do well to seek better counsel than that of Mr. Burke, who despite tireless typing exploits is seemingly incapable of finding truth that withstands expose.
Permalink to Comment4. Derek Lowe on October 25, 2005 11:52 AM writes...
Dr. S, I'd be lying if I said I didn't enjoy that.
Permalink to Comment5. daen on October 25, 2005 12:11 PM writes...
It's so nice to read WBurke's lucid, well-reasoned, intelligent prose again ...
Permalink to Comment6. Milo on October 25, 2005 12:56 PM writes...
Dr. Snowboard...
Two words: You Rock.
Permalink to Comment7. Timothy on October 25, 2005 2:59 PM writes...
Ahh, WBurke, where else could I turn for my daily dose of crazy?
Permalink to Comment8. Sigivald on October 25, 2005 3:31 PM writes...
I think the avoidability of lung cancer is probably the main reason there's less press and worry; everybody knows most of it can be avoided, and how to do so.
Breast cancer, though... can't really be avoided.
Permalink to Comment9. Marc on October 25, 2005 5:36 PM writes...
it is articles like these : [from slashdot]
http://chronicle.com/free/v52/i10/10a01401.htm
that make us distrust the never-ending flow of miracle cures.
Burried in some of these articles (ok, maybe not this one) are occasional good ideas or possibilities. By the time it gets to the front page, it has been blown out of proportion.
Scientists, Journalists and the end-readers all add their own optimism factor.
Permalink to Comment10. WBurke on October 26, 2005 7:17 AM writes...
Wow Dr. Snowshaft that was very illuminating - mirroring the very sad condition of the drug industry, aka Big Pharma, that they have little new to offer only copycat drugs and a tragically balloned sense of self-import.
I'd expect no less than that in a den of thives and delusional misfits. Carry on... Carry on...
Permalink to Comment11. daen on October 26, 2005 7:49 AM writes...
... a tragically balloned sense of self-import. ... a den of thives
Permalink to CommentGo on Burke ... give us all a laugh and try typing "trastuzumab" a few times.
12. WBurke on October 26, 2005 12:48 PM writes...
Daen, I can correct my spelling and typos quite easily, but your rotten soul condition and your willful ignorance of reality, well that would take a miracle to correct. One it would appear you have no desire to seek as you revel in your musings with the riffraff who frequent this cesspool of misinformation a veritable gathering of scientific gasbags.
Permalink to Comment13. daen on October 26, 2005 1:34 PM writes...
I can correct my spelling and typos quite easily
... once they're pointed out to you.
Permalink to Comment14. George on October 28, 2005 1:58 PM writes...
If the average person with an HER-2 positive breast cancer has a 50 % chance of relapsing with standard treatment, and 1 year of adjuvant herceptin cuts the recurrence rate by an extra 50% of what is left then that means that it improves the "cure" rate( if we presume that the benefit is sustained as the years go by), from 50% to 75% which is a pretty good result from the addition of one relatively non-toxic drug. It also means that one life is saved for every four patients given the drug. Also, the difference in disease free survival is now around 20% if you look at the latest graphs. Ladies - sell your houses!
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