Predicting the Outcome of Salvage Radiation Therapy

I've been following the work of Dr. Andrew Stephenson, of the Cleveland Clinic, who for several years has been trying to predict the outcome of salvage radiation, like the treatments I had this spring.

He, along with experts in the field like Scardino, Kattan, Slawin, and others, have just published an important paper in the Journal of Clinical Oncology. You can read a summary of the work here.

I obtained the full text of the document (you can too--just go to your nearest public library and tell them you need interlibrary loan). The full title is " Predicting the Outcome of Salvage Radiation Therapy for Recurrent Prostate Cancer after Radical Prostatectomy" from JCO, May 2007, pp. 2035-41.

Stephenson and his colleagues looked at 1,540 patients across 17 medical centers in North America. All of these patients underwent salvage radiation (an attempt to rescue the patient when surgery fails to eradicate prostate cancer). The researchers created a nomogram to predict the outcome of salvage radiation. The nomogram is in the public domain and will be available soon in an easy to use web version at http://www.nomograms.org soon.

In general, Stephenson found as he did in earlier work, that the earlier you can get started with salvage radiation, the better. He writes "The 6-year response to SRT among patients treated at PSA levels of 0.50 n/mL or less appears to be durable because only two progression events were observed after 6 years among 32 patients at risk at 6 years (median follow-up, 90 months)" (p. 2037). Besides the pre-radiation PSA, other important variables are Gleason score, PSA doubling time (PSADT), surgical margins, hormone therapy administered along with or before radiation, and lymph node metastasis. In earlier work, Stephenson had found that of patients at high risk (because of a Gleason >= 8, or rapid PSA doubling time) many could still benefit from radiation, especially if they had positive surgical margins like I did. This new study validated this idea.


In my case, the nomogram shows I have about a 55-57% chance of being progression free at 6 years out from radiation. Those are pretty good odds, I think. The flow chart in the article, which for me goes like this:

Pre-RT PSA <= 2.0, Gleason 4-7, Positive margins, doubling time <=10 months and that comes out to 57% probability of being progression free at 6 years. This study goes back to way before the days of IMRT, though, and the average man in the study got less radiation than I did. So I think my odds are probably better than 57%, since the targeting of radiation and dose escalation are much better these days than was the case for most of the study participants. Of course, if my cancer was already systemic, then the radiation probably didn't do much good. I should get some idea soon--I had blood drawn yesterday and I get the results in one week. So check back, dear reader, on or after June 15--will this blogger get on with his life and career? Or will he start putting affairs in order? ?