Just a day after launching a thread on cholesterol and prostate cancer I have become aware of a new, very encouraging study about the anti-cholesterol drug class "statins" and better results for prostate cancer patients having radiation. I'll cross reference this new thread, but this specific advance is too good to bury in that most encouraging but more general thread of yesterday.
For those who like to do their own research, here's the citation.
Int J Radiat Oncol Biol Phys. 2011 Mar 1;79(3):713-8. Epub 2010 May 6.
Improved biochemical outcomes with statin use in patients with high-risk localized prostate cancer treated with radiotherapy.
Kollmeier MA, Katz MS, Mak K, Yamada Y, Feder DJ, Zhang Z, Jia X, Shi W, Zelefsky MJ.
Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA.
The senior author is Dr. Michael Zelefsky, the highly respected radiation oncologist from the stand-out department at Memorial Sloan Kettering in New York City, the site of a number of major advances in radiation treatment for prostate cancer.
They looked at 1,681 men who had had radiation for clinically localized prostate cancer (stages T1-T3) who were all treated with conformal radiation at a median dose (meaning half got lower, half got higher) of 81 Gy (the modern dosing range that has proven much more effective) between 1995 and 2007, and for whom lists of pre-radiation medications were available. About half of the men had had a short course of androgen deprivation therapy (hormonal therapy) in support of their radiation.
What they found was that the five year PSA relapse free survival rate for those on statins was 89% (very good for external beam radiation at the five year point, especially considering that there were some higher risk stage T3 patients involved and probably some higher risk stage T2b patients) compared to 83% for for those not taking a statin. They also took a snapshot at eight years, finding that the success rate was 80% for statin users versus 74% for non-statin users. A statistical test showed an extremely small possibility that the results were due to chance and artificial, which is encouraging.
Now for the drum roll: among the men taking statins, only high risk patients showed improvement in the success rate!
That is a great finding as other patients are likely to have been cured by the radiation, whereas the high risk group is the group that really needs extra help! It appears that the improvement in results was nearly 50% (hazard ratio 0.52, p-0.02 for those with a statistical bent).
The authors also commented that their results suggest not only anticancer activity for statins but also that statins sensitize prostate cancer cells to radiation!
The two questions I have about the study are whether the distribution of the riskier patients was even, especially the stage T3 patients, and whether both groups got about the same radiation. Hopefully they were more or less equally distributed between the statin and non-statin groups, as a preponderance of T3 patients in the non-statin group could have skewed the results. Similarly, if a preponderance of patients in the non-statin group got radiation doses of significantly less than 78 Gy, that too could distort the results. I'm quite confident that neither distortion occurred as Dr. Zelefsky is a noted researcher who almost certainly would have paid attention to a substantial imbalance and commented on it. They did perform the kinds of statistical tests that should have teased out the real relationships. I would like to know the risk distribution of the patients in the two groups; all had localized though not always confined prostate cancer, but the PSA and Gleason characteristics were not provided in the study abstract.
As far as I know, knowledge of the relationship of statins and radiation for prostate cancer is fresh, though the report was electronically available about a year ago. I haven't seen this news in any of the newsletters I follow, though I may have missed it. Dr. Freeman, who spoke at the IMPaCT conference described in the thread on cholesterol did not mention it either. That leads me to conclude that we are dealing with a great advance in knowledge here. Moreover, it seems reasonable that statins would also boost results for patients having other forms of radiation. This looks like a game-changer to me!
I'm interested what our radiation veterans think about this and whether they had been aware of it.
I'll sum up my reaction to this study in one word: Wow
! Okay, I need to add another word: AWESOME
Take care all,