Over the past few years, sex-based differences in lung cancer have become increasingly recognized as relevant in prognosis overall and potentially in predicting response to treatment, such as EGFR inhibitors and other targeted therapies. At ASCO 2007, a group led by Dr. Kathy Albain, long committed to learning more about sex differences in lung cancer outcomes, presented a review of results from a series of six recent chemotherapy-based trials conducted by the Southwest Oncology Group (SWOG) in the setting of advanced NSCLC, divided by patient sex (abstract here):
(Click to enlarge)
Among the 1334 patients enrolled in these six trials, 36% were women; having women under-represented on lung cancer trials is unfortunately typical (although better than it used to be in the US, and still much better than in European trials, where women constitute just 10-15% of patients in some studies). Women and men didn’t differ in their characteristics going into the trial, such as age, performance status, and stage, but women were a little less likely to have weight loss of 5% of baseline weight or more compared to men (33% vs 41%).
Despite starting out with the same characteristics as the men and experiencing a very similar range and severity of treatment-related side effects as men, women had a significantly better overall survival than men, with a median survival of 11 vs. 8 months, a one year survival of 46% vs. 35%, and a two-year survival of 19% vs. 13% (P = 0.02 for the entire overall survival analysis by sex):
But it really wasn’t all women. Instead, the better survival was limited to women over 60, while women and men under 60 had a very similar survival:
That may sound surprising, but we’re seeing more and more that hormonal differences may be pretty important. Next I’ll describe some of the mounting evidence that is converging to show that women with high serum estradiol levels (a premenopausal picture) don’t do as well as women with low serum estradiol levels most commonly seen in older, post-menopausal women.
posted by Dr. West @ 12:47 pm link to this post
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August 5th, 2007 at 8:22 pm
Doesn’t chemo pretty much send most women into menopause? I probably don’t understand the menopause subject very well, and maybe hormone levels vary depending on how long you’ve been in it? It just seems as though pre-menopausal women w/ LC would quickly become post-menopausal, so I’m not sure that I understand.
August 5th, 2007 at 8:35 pm
Well, these are assessments of whether they’re menopausal before the start of treatment, and the effects of chemo on women in terms of going into menopause is pretty variable. In general, many premenopausal women do at least have a suspension of periods, but younger ones who are further from their true menopausal age are more likely to have a little or no interruption and resume their periods again.
I’ll show a little bit of work on estradiol levels in the next post, and I’m not sure at all what happens to the estradiol levels of premenopausal women as they receive chemo. As far as I’m aware, there has been remarkably little research on this thus far; we’re only just starting to appreciate how relevant these issues might be.
-Dr. West
August 5th, 2007 at 8:55 pm
And, how does HRT play in this picture. Since, until recently, many post-menopausal women were receiving HRT, either estrogen alone or with progesterone, has the research taken this into account?
August 6th, 2007 at 3:28 pm
I’ll get into the little known about hormone levels in the next post in this subject.
August 6th, 2007 at 7:02 pm
Speaking of sex-based differences as relevant in (potentially) predicting response to treatment, an oncologist has once said that whereas women do better with EGFR inhibitors, MEN DO BETTER WITH AVASTIN (I’m not sure if that will extend to all anti-angiogenic agents). Has anyone heard the same or seen data supporting the second part of the statement?