“If all you have is a hammer, everything looks like a nail”


It was called “instrument bias” by Abraham Maslow and Abraham Kaplan, but for present purposes, we’ll call it “specialty bias” — over-reliance on the tool one is most familiar with.

Kishan et al. conducted a survey among urologists (“UROs”) and radiation oncologists (“ROs”) concerning their opinions about how best to treat high-risk prostate cancer patients in various situations from initial treatment to recurrence after initial treatment. They tabulated responses from 846 ROs and 407 UROs:

  • 63 percent of ROs and 96 percent of UROs practiced in the US; the rest mainly in Australia and NZ.
  • They had a median of > 10 years of experience.
  • 41 percent of ROs and 51 percent of UROs were in private practice.

Initial Treatment of High-Risk Patients

ROs were five times more likely to believe that initial treatment with radiotherapy (RT) with androgen deprivation therapy (ADT) and with local salvage therapy, if needed, was preferred. They were also twice as likely to believe that it offered the patient equivalent outcomes as radical prostatectomy (RP) and salvage radiation (SRT), if needed.

UROs were four times more likely to believe that RP ± SRT was the preferred treatment. Only 29 percent of UROs believed that RT had a place in initial treatment.

The “right” answer is…

Currently, the American Urological Association (AUA) and the American Society of Radiation Oncologists guidelines state that:

Clinicians should recommend radical prostatectomy or radiotherapy plus ADT as standard treatment options for patients with high-risk localized prostate cancer. (Strong Recommendation; Evidence Level: Grade A)

NCCN guidelines also list both as options. They note, however (see MS25):

A large, multicenter, retrospective cohort analysis that included 1809 men with Gleason score 9–10 prostate cancer found that multimodality therapy with EBRT, brachytherapy, and ADT was associated with improved prostate cancer-specific mortality and longer time to distant metastasis than either radical prostatectomy or EBRT with ADT. In addition, an analysis of outcomes of almost 43,000 men with high-risk prostate cancer in the National Cancer Database found that mortality was similar in men treated with EBRT, brachytherapy, and ADT versus those treated with radical prostatectomy, but was worse in those treated with EBRT and ADT.

This can only be decided definitively by a randomized clinical trial, but given the difficulties of recruiting for such a trial, patients must make the decision based on lower level evidence.

Adjuvant RT (ART) and SRT for High-Risk Patients after RP

ROs were 2.7 times as likely to advocate for ART with undetectable PSA, and were twice as likely to believe that ART is underutilized. Conversely, UROs were 2.5 times more likely to approve of waiting until PSA has risen to 0.2 ng/ml. Most believed it is utilized appropriately (it is seldom utilized in this situation) or over-utilized. About 2 in 5 ROs and UROs were OK with early SRT.

Two-thirds of ROs thought SRT was appropriate with two consecutive rises, or at any detectable level or any level under or equal to 0.1. Less than half of UROs held that belief. ROs were more likely than UROs to believe that SRT is underutilized.

The “right” answer is…

The 2019 AUA/ASTRO guidelines state that:

Guideline Statement 2. Patients with adverse pathologic findings including seminal vesicle invasion, positive surgical margins, and extraprostatic extension should be informed that adjuvant radiotherapy, compared to radical prostatectomy only, reduces the risk of biochemical recurrence, local recurrence, and clinical progression of cancer. They should also be informed that the impact of adjuvant radiotherapy on subsequent metastases and overall survival is less clear; one of three randomized controlled trials that addressed these outcomes indicated a benefit but the other two trials did not demonstrate a benefit. However, these two trials were not designed to identify a significant reduction in metastasis or death with adjuvant radiotherapy. (Clinical Principle)

Guideline Statement 3. Physicians should offer adjuvant radiotherapy to patients with adverse pathologic findings at prostatectomy including seminal vesicle invasion, positive surgical margins, or extraprostatic extension because of demonstrated reductions in biochemical recurrence, local recurrence, and clinical progression. (Standard; Evidence Strength: Grade A)

Guideline Statement 8.Patients should be informed that the effectiveness of radiotherapy for PSA recurrence is greatest when given at lower levels of PSA.  (Clinical Principle)

… patients should be advised that if recurrence is detected without evidence of distant metastases, then RT should be administered at the earliest sign of PSA recurrence …

The 2019 NCCN guidelines state:

Indications for salvage RT include an undetectable PSA that becomes subsequently detectable and increases on 2 measurements or a PSA that remains persistently detectable after RP. Treatment is more effective when pre-treatment PSA is low and PSADT is long.

Salvage for High-Risk Patients after RT

About two-thirds of UROs believed that RP and cryotherapy are appropriate salvage therapies after biochemical recurrence following primary RT (when imaging was negative for distant metastases). Very few thought salvage radiation or other ablation therapies were appropriate. Among ROs, most approved of salvage RP, but sizeable minorities felt that salvage brachytherapy and salvage cryotherapy was appropriate. About one in five thought salvage SBRT or salvage HIFU was appropriate.

However, two-thirds of both ROs and UROs agreed that salvage after RT was not as effective as salvage after RP.

And most of both groups believe that focal salvage is inferior to whole-gland salvage after RT failure, but UROs were much more likely to hold this belief vs ROs.

The “right” answer is…

NCCN guidelines state:

Salvage RP is an option for highly selected patients with local recurrence after EBRT, brachytherapy, or cryotherapy in the absence of metastases, but the morbidity (ie, incontinence, loss of erection, anastomotic stricture) is high and the operation should be performed by surgeons who are experienced with salvage RP.

Brachytherapy can be considered in men with biochemical recurrence after EBRT. In a retrospective study of 24 men who had EBRT as primary therapy and permanent brachytherapy after biochemical recurrence, the cancer-free and biochemical relapse-free survival rates were 96% and 88%, respectively, after a median follow-up of 30 months. Results of a phase 2 study of salvage HDR brachytherapy after EBRT included relapse-free survival, distant metastases-free survival, and cause-specific survival rates of 68.5%, 81.5%, and 90.3%, respectively, at 5 years.

HIFU also has been studied for treatment of radiation recurrence. Analysis of a prospective registry of men treated with HIFU for radiation recurrence revealed median biochemical recurrence-free survival at 63 months, 5-year OS of 88%, and cancer-specific survival of 94%.

For a discussion of salvage therapies after RT, see this link. Salvage after RT is generally as effective or better than SRT after RP. Focal salvage is as effective as whole-gland salvage in many cases.

What to Do about Specialty Bias

It is not surprising that specialists are more knowledgeable about, and more favorably disposed to their own field (otherwise, they’re in the wrong job). However, there are knowledge gaps even within their own field. Many patients expect their doctors to be knowledgeable about their own field, and to be able to compare it to other therapies. We have seen that this is an unrealistic expectation.

Here are some recommendations for patients:

  • Don’t expect a specialist to be knowledgeable outside his own field. Consult with a variety of specialists, if possible.
  • Remember that it is radiation oncologists, not urologists, who treat and follow-up on SRT for surgical recurrences. ROs are more experienced than UROs at SRT.
  • Salvage brachytherapy after RT recurrence is highly specialized – there aren’t many practitioners with expertise. Salvage ablation and salvage SBRT specialists are even more rare. Patients should avoid salvage surgery due to its high morbidity.
  • Second opinions are critical. Finding specialists may involve travel, which may be precluded by cost/insurance limitations.
  • For patients who are inclined to research these topics themselves, they must be aware that the quality of research on all of these topics is low to moderate. There have been very few randomized clinical trials focused on high-risk patients, so we have to make informed judgments based on observational studies or single-arm, single-institution clinical trials in most situations. AUA, ASTRO, and NCCN guidelines are updated and may be the best source of information (other than this website 😉).

Focusing on physicians, the authors recommend interdisciplinary clinics, which might work well in academic centers. However, a substantial proportion of both ROs and UROs were in private practice. They also suggest continuing medical education, and cross-specialty training. Professional organizations typically do not currently require cross-specialty training. UROs do not typically attend ASTRO meetings, nor do ROs typically attend AUA meetings.

Editorial note: This commentary was written by Allen Edel for The “New” Prostate Cancer InfoLink. Allen thanks Dr. Christopher King of the University of California, Los Angeles, for allowing him to see the full text and questionnaire.

7 Responses

  1. Reblogged this on Dan's Journey through Prostate Cancer and commented:

    Here’s an interesting article that a former boss of mine would call a “B.G.O.” — a blinding glimpse of the obvious.

    If you go to a radiation oncologist, they’re likely to recommend radiation as your treatment option of choice, and if you go to a urologist, they’re more likely to recommend surgery. Duh!

    This study was focused on treatment of patients with high-risk prostate cancer. I’d be interested to see if the recommendations become a little more muddied for those of us with Gleason 3 + 4 or 4 + 3. I’d really like to see what their answers would be to the last question in the second table: Lowest PSA at which SRT is appropriate. That’s of obvious interest to me.

  2. Dan,

    One of the reasons they focused on high-risk patients is because of the paucity of available data, creating greater uncertainty about ideal treatments. Because high risk constitutes only about 5% of patients, it is a very hard group to research — its difficult to recruit enough patients quickly enough to conduct prospective clinical trials. For that reason, doctors have to rely on lower levels of evidence — retrospective and database analyses — that are fraught with selection bias and non-comparable treatments.

    Fortunately, there are a lot more data available on low- and intermediate-risk patients, and there is, at least, the ProtecT randomized controlled trial (RCT) that provides some randomized comparative data. Of course, as the specs for the sub-groups get more focused — say, among those with a Gleasons score of 4 + 3 = 7 with rising PSA after prostatectomy — it becomes harder to study. But even in the larger groups, there are important knowledge disparities between ROs and UROs in community practice.

  3. I think there is an error for the adjuvant radiation therapy responses. You state that ROs are 2.7 times more likely to choose ART but the number for UROs you wrote is 61% when it probably should be about 16%.

  4. Regarding the seeming inferiority of EBRT in guideline MS25 above:

    As someone who had to select a kind of radiation for a once life-threatening case, I became acutely aware of the key role that EBRT dose differences made in success, basically meaning non-recurrence. In essence, in earlier years EBRT radiation was inadequate for many patients because the doses were too low, basically with grey levels in the high 60s/low 70s. The referenced guideline falls into this pit, in my opinion.

    Table 2 of the study referenced in the guideline, shows that the average dose for the EBRT group was just 74.3 Gy, with a range from 65 to 81.4 Gy, which is not surprising for a study for patients treated from 2000 to 2013, for which period men in the earlier years were extremely likely to get doses below the typical doses of 78 to 81 Gy for treatments in recent years (and the latter years of this study). It is now well-known that the “escalated dosing” range is associated with substantially superior results. Of course we also now know that a long course of ADT to support radiation is best for high-risk patients. In this study, that was recognized, but non-use of ADT was not an exclusion criterion. ADT use for the two radiation group is detailed in “eTable 4. Distribution of EBRT and EBRT + BT Patients by ADT Duration,” but I was not able to access it. I’m presuming that most patients would have also been on ADT for at least several months if not for a long course.

    In other words, it is reasonable to expect that if those 734 men in the EBRT group were to be treated with escalated dose EBRT plus ADT today, their success rate would be considerably closer to the success rate of men treated with EBRT, brachy and ADT in the study.

    Thanks, Allen, for this well-done report on RO vs. URO preferences!

  5. Dr Chodak:

    Thanks for catching that. The numbers in my original were exactly as you say: 43% for ROs and 16% for Uros. I’m sure Mike will correct that.

  6. Jim:

    That is exactly the question that was addressed by ASCENDE-RT. The EBRT-only group received an escalated prostate dose — 78 Gy. Both groups received 12 months of ADT. Brachy-boost had significantly superior oncological outcomes. See here.

  7. Gerry/Allen:

    Error corrected. All my fault. Typo when building table.

    Mike

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