What different specialists believe about adjuvant radiation therapy


A recent study published in “The Red Journal” suggests (perhaps not surprisingly) that radiation oncologists and urologists have different mindsets about the application of immediate adjuvant radiation therapy following surgery for prostate cancer patients with a variety of adverse pathologic risk factors.

Showalter et al. invited 926 radiation oncologists and 561 urologists to complete a web-based survey that asked questions about these physicians’ policies and beliefs regarding immediate adjuvant radiation therapy. The adverse pathologic risk factors that were specifically listed as being potential indicators for adjuvant radiation included:

  • Extracapsular extension
  • Seminal vesicle invasion
  • Positive surgical margin(s)

Here is what they found:

  • The overall response to the survey was only 20 percent.
  • Surveys were completed by
    • 218/926 radiation oncologists (23.5 percent)
    • 92/519 urologists (17.7 percent)
  • Based on the adverse pathologic features provided, adjuvant radiation was recommended by
    • 68 percent of all respondents
    • 78 percent of radiation oncologists who responded
    • 44 percent of urologists who responded
  • Urologists were significantly less likely than radiation oncologists to agree that adjuvant radiation improves survival and/or biochemical control (p < 0.0001).
  • PSA thresholds for salvage (as opposed to adjuvant) radiation therapy were higher among urologists than among radiation oncologists (p < 0.001).
  • Predicted rates of erectile dysfunction as a consequence of radiation therapy were higher among urologists than among radiation oncologists (p <0.001).
  • On multivariate analysis, respondent specialty was the only predictor of recommendations about use of adjuvant radiation therapy.

There are most certainly data that suggest that immediate adjuvant radiation therapy can extend the overall survival of men with high-risk features after first-line radical prostatectomy. However, the data from these trials are perhaps not as compelling as some would like to believe. One of the major trials (in the USA) that attempted to address and resolve this question never enrolled sufficient patients. Another, carried out largely in the UK, combined adjuvant radiation with adjuvant hormone therapy, which is a much more aggressive form of treatment.

The basic problem here is that we have really failed — to date — to differentiate between the value of adjuvant radiation and salvage radiation therapy based on all the risk factors for individual patients. There might well be consensus between the urologists and the radiation oncologists that adjuvant radiation (perhaps with neoadjuvant and adjuvant hormone therapy too) was a good idea for this patient:

  • GK is 52 years of age, diagnosed with a PSA of 4.8 ng/ml, Gleason 8, with 7/12 positive biopsy cores. After robot-assisted surgery he is pT3a, still Gleason 8, with one positive surgical margin, and an initial nadir PSA of 0.18 ng/ml.

However, its value in the following patient is not as immediately evident:

  • RL is 67 years of age, diagnosed with a PSA of 4.9 ng/ml, Gleason 8, with 5/12 positive biopsy cores. After robot-assisted surgery he is pT3a, still Gleason 8, with negative surgical margins, and an initial nadir PSA of 0.01 ng/ml.

At present the appropriate use of immediate adjuvant radiation therapy is really a judgment call, based on the individual characteristics of the individual patient and on the risks that that patient is willing to take. It is hardly surprising that most surgeons want to take some time to see if the patient is in full remission after a radical prostatectomy. By comparison, it is also hardly surprising that the radiation oncologists want to give adjuvant radiation early — when the chances of it working best in the men who most need adjuvant radiation are at their highest.

As Showalter et al. note in their conclusions, what we really need is further research to better define the toxicities of second-line radiation therapy in patients who have received first-line radical prostatectomy and on better identifying subgroups of patients who will really gain  from immediate adjuvant radiation therapy as compared to deferred (salvage) use of radiation.

7 Responses

  1. That pretty much matches my experience exactly. I was in the RL camp but 20 years younger (all the indications listed but undetectable PSA after surgery). Surgeon was pretty downbeat when he gave me the news but didn’t seem to want to take any further action. He referred me to a medical oncologist, someone who is pretty well known and generally conservative. The SWOG 8794 results (which I think you refer to above) had just come out though, and to the surgeon’s great surprise the oncologist told me to see a radiation oncologist. I got differing radiation opinions from the two doctors I saw. Whether to radiate now, how much ADT, and whether to include the lymph nodes. I sought still more advice and got more differing opinions. Having decided to radiate at that point I went with the most aggressive treatment on offer. Two and a half years out from surgery, my PSA is still <0.01, but my bladder is shot, I have lymphedema, and sexual function is possible but requires creativity. So I guess I got what I paid for.

    :)

  2. And all that I can offer in response to Richard’s comment above is that it demonstrates with great precision just how extremely difficult making these decisions can be for all concerned.

  3. What would be very useful are: (i) better tools to predict future biochemical failure, (ii) better lymph node imaging, and (iii) studies to prove that addressing the lymph nodes with radiation actually helps. I hope that the NADiA® ProsVue™ ultra-sensitive PSA test can help with the first of these. It is unfortunate that Combidex MRI for lymph node detection failed to get FDA approval, but I have heard that other iron nano-particle tests are under investigation. And for (iii) I don’t know of any studies and I guess it is pretty hard without an accurate test but it seems like more radiation oncologists are coming around to the opinion that pelvic lymph nodes can be successfully addressed in high-risk patients before the disease has spread further. The urologist I see now definitely thinks I had too much radiation.

  4. Could someone please comment on my observation that the standard of care for T3aN0M0 in the face of a surgical finding of capsule breach is either adjuvant radiation or salvage radiation at the point of identification of remaining PSA?

  5. Dear Jo:

    There is no well-defined standard of care for clinical stage T3aN0M0. If there is extracapsular extension through the capsule of the prostate, the appropriate care would depend on the size of the extension and how far the extension went into the surrounding tissue, the Gleason score of the patient (at biopsy and at surgery — if surgery is carried out), the patient’s original PSA at the time of diagnosis, and perhaps other factors as well.

    T3aN0M0 disease can normally and appropriately be treated with any one of: (a) first-line surgery alone; (b) first-line surgery followed by adjuvant radiation therapy (with or without adjuvant hormone therapy); and (c) various types of first-line radiation therapy (with or without hormone therapy). If surgery is the first-line treatment, the decision whether to use adjuvant radiation and adjuvant hormone therapy would normally depernd on exactly what was found at the time of surgery.

    Salvage radiation therapy (again with or without adjuvant hormone therapy) is the standard treatment for a man with a rising PSA at any time after first-line surgery if and only if it is believed that the cancer is still confined to the prostate bed or the immediate anatomic area of the pelvis.

  6. Would the belief in confinement to the prostate bed or the immediate area be determined by scans, i.e. MRI, bone scan, etc?

  7. Dear Jo:

    It can be extremely difficult to determine whether recurrence is confined to the prostate bed. This is most likely to be the case in men who gave every sign of having truly localized disease prior to their first-line treatment and who have a positive biopsy of a suspicious area after the recurrence. Neither a bone scan nor any other currently known imaging technique can determine with absolute certainty that a patient’s recurrence is actually localized to the prostate bed or the immediately surrounding tissues. Many early recurrences are far too small to be visible using currently available imaging technologies (up to and including PET scans).

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