What are the outcomes of 3-dimensional conformal radiotherapy (3D-CRT) for the treatment of prostate cancer?

Updated: Nov 29, 2018
  • Author: Isamettin Andrew Aral, MD, MS; Chief Editor: Edward David Kim, MD, FACS  more...
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Answer

The results of 3D-CRT demonstrate superior bNED (biochemical, no evidence of disease) control rates, largely because of the ability to escalate the dose with less concern over the toxicity to normal tissue. 3D-CRT allows delivery of higher doses of radiation to the prostate without significant complications to the normal tissue.

Even small degrees of dose escalation have been shown to improve the biochemical outcome in patients diagnosed with prostate cancer. Comparison studies have shown superior outcomes with doses of 78 or 79 Gy versus doses of 70 Gy. [14, 15]

The 5- and 10-year follow-up results with 3D-CRT indicate increased rates of bNED control, especially in patients with intermediate prognostic factors (ie, Gleason score of 7 and PSA level of 10-20 ng/mL). The bNED rates in patients with pretreatment PSA levels of 10-20 ng/mL are approximately 30% better than those in patients treated with conventional radiotherapy at 5 years.

Patients with more favorable prognostic factors (ie, Gleason score ≤ 6 and PSA level ≤ 10 ng/mL) may not benefit from dose escalation, although this issue remains highly controversial. Similarly, the bNED rates in patients at high risk for locally or regionally advanced disease (ie, Gleason scores of 8-10 and PSA ≥ 20 ng/mL) may not markedly improve after dose escalation, probably because this group of patients is ultimately at higher risk for distant metastasis.


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