The co-authors of Invasion of the Prostate Snatchers, blog alternate posts weekly. We invite you to post your comments.

Tuesday, July 7, 2015

Active Surveillance for Men with Intermediate Risk Prostate Cancer


People are starting to become familiar with the modern way of conceptualizing prostate cancer.  When men are newly diagnosed, they are split into three broad categories: Low-Risk, Intermediate-Risk and High-Risk. This system, which was invented by Dr. Anthony D’Amico, is helpful for the proper selection of optimal treatment; men with more favorable types of prostate cancer can receive milder therapy and still maintain normal survival rates.
As far as treatment selection is concerned, as a general rule of thumb, men with Low-Risk disease are encouraged to simply monitor the disease, withholding therapy altogether unless tumor growth is detected on subsequent testing.  At the other extreme, men with High-Risk disease typically undergo combination treatment with three forms of therapy: seed radiation, IMRT and hormone therapy, which is continued for a year and a half.
Treatment recommendations for men with Intermediate-Risk range widely from surgery, to the many types of radiation—IMRT, seed implants, SBRT and Proton therapy to focal therapy, as well as the alternative of simply giving hormone therapy by itself. This wide variety of treatment options is not merely a result of physician bias.  It turns out that the types of cancer that occur in the Intermediate-Risk category also vary widely.  At the “good” end of the spectrum, men with the favorable type of Intermediate-Risk disease have a condition that behaves more like Low-Risk while cancers men at the unfavorable end of the Intermediate-Risk spectrum have a condition that behaves more like High-Risk.
The indicators that define an unfavorable type of Intermediate-Risk disease are multiple intermediate characteristics rather than having a single Intermediate-Risk factor.  For example, it is considered unfavorable when the PSA is over ten and the Gleason is 4 + 3 (instead of 3 + 4) and there are more than 50% of the biopsy cores containing cancer.  At the other extreme are men with the favorable type of Intermediate-Risk disease. These men are characterized by having all the Low-Risk factors in combination with only a single Intermediate-Risk factor.
Making a proper distinction between the favorable and unfavorable types of intermediate risk disease can be monumentally important as it relates to treatment selection. Studies show that men with favorable Intermediate-Risk disease are potential candidates for active surveillance.  A recently published report at this year’s Genitourinary ASCO meeting bears directly on this issue:
In Abstract #82 from the meeting, authored by Ann Caroline Raldow from Harvard, 6500 newly-diagnosed men treated with radiation and hormone therapy at the Chicago Prostate Cancer Center between 1997 and 2013 were evaluated.  Dr. Raldow calculated their survival rate after treatment based on their risk category: low, favorable-intermediate, unfavorable-intermediate, and high. Eight years after treatment 820 men had died, 72 of them from prostate cancer. Men in the favorable Intermediate-Risk category had the same survival rates as men in the Low-Risk category.  Men in either the High-Risk category or in the unfavorable Intermediate-Risk category demonstrated an increased mortality rate from prostate cancer.
Bottom line, the cancer of men with the favorable type of Intermediate-Risk prostate cancer behaves the same as Low-Risk.  Dr. Raldow’s analysis provides further clinical evidence that men with the favorable type of Intermediate-Risk prostate cancer can forgo immediate radical therapy and embark on active surveillance.


Anonymous said...

Having recently been diagnosed (Gleason 3+4) and having undergone HDR (used in this study), this abstract was interesting, but raised many questions (perhaps answered in the full text).

Isn't it a rather large leap to conclude that because the prostate cancer mortality was similar between the low and favorable intermediate-risk groups undergoing treatment that they would behave the same without treatment? The cancer mortality was very low in both groups (less than 1%). So was the treatment effective in the favorable intermediate risk group and just overkill in the low risk group?

They mention "high dose radiation therapy and androgen deprivation therapy as appropriate. Does that mean the groups were treated differently? How much differently? Did everyone get ADT? I got HDR as monotherapy because of my favorable risk status, and I've heard that ADT isn't all that helpful when combined with radiation for intermediate risk patients, but I'm not sure this was the case at the beginning of the study back in 1997.

Also, how much of the similar behavior in the two lowest risk categories is because most (or all) of the biopsies were random and missed some Gleason 7's in the low risk group?

I guess with today's imaging, active surveillance means something different that it did just a few years ago. I'm not sure I would be brave enough to trust that my slightly more aggressive (than Gleason 6) cancer didn't microscopically spread outside my prostate while watching it. I had 9 of 9 cores with Gleason 7 (MRI directed--3 each in 3 lesions), so I'm pretty sure I really have Gleason 7, but this study wouldn't be giving me the courage to do AS.

Then again, not so long ago, and I'm sure even today, Urologists were/are ripping out Gleason 6 prostates and telling their patients they don't have time for a second opinion.

This will be interesting to watch. Hopefully some genetic typing can provide further clues.

Robert Young said...

He doesn't mention surgery for any treatment