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Ibrance and Letrozole: Newly Diagnosed Treatment
Breast Cancer | Last Active: Jan 22, 2023 | Replies (104)Comment receiving replies
@callalloo the conclusions of this study were more complicated, mainly because of missing date that affected results. All in all the article you linked favors the use of both drugs, Femara and Ibrance (brand names). I urge people to read the entire article and not just the headline, which is misleading. I am posting excerpts and hope people will read them.
"To demonstrate the impact of missing data, Dr. Finn showed a post hoc analysis excluding patients for whom survival data were not available. In that analysis, the median overall survival was 51.6 months with palbociclib/letrozole vs 44.6 months with letrozole alone (HR = 0.869; 95% CI = 0.706–1.069)."
"The time to chemotherapy was 38.1 months with palbociclib/letrozole vs 29.8 months with letrozole alone (HR = 0.730; 95% CI = 0.607–0.879)."
"Regarding other outcomes that affected quality of life, Dr. Finn reported the median duration of treatment and the time to chemotherapy were prolonged with palbociclib plus letrozole. The median treatment duration was 22.0 months vs 13.8 months, and at each benchmark, more of the palbociclib arm were still on treatment. “At 6 years or longer, this was three times as many (16% vs 5%),” he noted."
" For the largest subgroup of patients—those with a disease-free interval of more than 12 months—overall survival increased from 44.6 months in the control arm to 64.0 months with palbociclib/letrozole"
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I included the link so that people can read the whole article and am glad that you did. In a few places the author noted where the results of both drugs v. letrozole and a placebo or letrozole alone "were not statistically significant." I assume that it is that, that points to a lack of clear benefit that led to the headline conclusion.
The authors cited the problem of missing data as you noted. But statistically-valid conclusions cannot be drawn by ignoring missing data in such a study. That would be cherry-picking data or biased outcome.
So they mentioned what they could deduce (which you excerpted) from the incomplete data but nonerheless concluded as stated in the headline. At least that's what I deduce from the seeming discrepancies.
It would be valuable to know the cause of the missing data. E.g., if people dropped out if the study and why. And why it was the missing data was "disproportionate"? One reason people drop our of studies is adverse effects. In such a case, had the people stayed in the study, several of the measure variables would have been negatively affected.
But here's one conclusion from the study and the link again for anyone interested.
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“Overall survival was numerically longer in the palbociclib-plus-letrozole arm, but the results were not statistically significant,” Dr. Finn announced. “The interpretation of overall survival is limited by the large and disproportionate percentage of patients with missing survival data [ie, lost to follow-up or censored] between the treatment arms.”
https://ascopost.com/news/july-2022/no-overall-survival-benefit-reported-with-palbociclibletrozole-in-advanced-breast-cancer/?utm_source=TAP%2DEN%2D072622&utm_medium=email&utm_term=4cf962011c9ee11a42cbb2ed9ce1807f