Earlier, intense radiation after prostatectomy benefits patients

9 Feb 2015

Prostate cancer patients with detectable prostate specific antigen (PSA) after radical prostatectomy should receive earlier, more aggressive radiation therapy treatment. This is according to a study published in the International Journal of Radiation Oncology, the official scientific journal of the American Society for Radiation Oncology.

This study is a 10-year post-treatment analysis of a German prospective clinical trial (codenamed ARO 96-02). The trial compared a wait-and-see approach versus an adjuvant radiation therapy approach for patients with node negative prostate cancer who had a prostatectomy.

Detailed clinical design and results

The clinical trial accrued 388 patients between 1997-2004 from 22 centers in Germany. Patients had prostate cancer with positive or negative margins (classified as "pT3-4pN0") who had already undergone radical prostatectomy.

After their prostatectomy, patients were grouped as follows:

  • Arm A: 159 patients who reached an undetectable PSA, followed a wait-and-see approach
  • Arm B: 148 patients who reached an undetectable PSA, received radiation therapy (in particular, 60 Gy of 3D conformal radiation therapy).
  • Arm C: 78 patients who did not reach an undetectable PSA, received radiation therapy (in particular, 66 Gy of 3D conformal radiation therapy).

Follow-up was conducted for all eligible patients in the trial quarterly for the first 2 years, twice a year from 3 to 6 years post-treatment and annually thereafter.

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During the study:

  • In Arms A and B7% patients experienced distant metastasis
  • In Arm C16% experienced distant metastasis.
  • In Arm C, 58% of patients also underwent hormone therapy as a result of recurrence (at the discretion of the attending physician).
  • In Arm C, 7 of the 48 patients who had data available reached an undetectable PSA after completion of salvage radiation therapy.

Regarding side effects:

  • 7 patients experienced severe late effects with 5 patients reporting grade 3 bladder impairment, and 2 patients reporting grade 2 bladder impairment.
  • In Arm C:
    • 68% did not report any genitourinary late toxicity, and 80% did not report any gastrointestinal late toxicity.
    • Patients with detectable PSA post-prostatectomy experienced limited side effects as a result of radiation therapy and they did not report any grade 3 or grade 4 acute toxicities.

Optimistic outcomes on 10-year overall survival

Clinical relapse-free survival (cRFS) and overall survival (OS) were calculated (using a method called Kaplan-Meier).

Hence:

  • Patients in Arm A had a 10-year OS rate of 8%
  • Patients in Arm B had a 10-year OS rate of 83%
  • Patients in Arm C had a 10-year OS rate of 68% and a 10-year cRFS rate of 63%.

"The impact of PSA persistence on 10-year overall survival is evident based on this new analysis. Improved imaging or surrogate markers beyond PSA are desirable to distinguish risk groups among men with PSA persistence. Larger, prospectively randomized clinical trials should examine additional treatment options to come to a standardized therapy for prostate cancer patients with PSA persistence" indicated Thomas Wiegel, MD, director of the radiation oncology department at University Hospital Ulm in Ulm, Germany, and lead author of the study.

 

Source: eCancer News
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