Dose escalation with three-dimensional conformal radiation therapy affects the outcome in prostate cancer Journal Article

Authors: Zelefsky, M. J.; Leibel, S. A.; Gaudin, P. B.; Kutcher, G. J.; Fleshner, N. E.; Venkatramen, E. S.; Reuter, V. E.; Fair, W. R.; Ling, C. C.; Fuks, Z.
Article Title: Dose escalation with three-dimensional conformal radiation therapy affects the outcome in prostate cancer
Abstract: Purpose: Three-dimensional conformal radiation therapy (3D-CRT) is a technique designed to deliver prescribed radiation doses to localized tumors with high precision, while effectively excluding the surrounding normal tissues. It facilitates tumor dose escalation which should overcome the relative resistance of tumor clonogens to conventional radiation dose levels. The present study was undertaken to test this hypothesis in patients with clinically localized prostate cancer. Methods and Materials: A total of 743 patients with clinically localized prostate cancer were treated with 3D-CRT. As part of a phase I study, the tumor target dose was increased from 64.8 to 81 Gy in increments of 5.4 Gy. Tumor response was evaluated by post-treatment decrease of serum prostate-specific antigen (PSA) to levels of ≤1.0 ng/ml and by sextant prostate biopsies performed ≤2.5 years after completion of 3D-CRT. PSA relapse-free survival was used to evaluate long-term outcome. The median follow-up was 3 years (range: 1-7.6 years). Results: Induction of an initial clinical response was dose-dependent, with 90% of patients receiving 75.6 or 81.0 Gy achieving a PSA nadir ≤1.0 ng compared with 76% and 56% for those treated with 70.2 Gy and 64.8 Gy, respectively (p < 0.001). The 5-year actuarial PSA relapse-free survival for patients with favorable prognostic indicators (stage T1-2, pretreatment PSA ≤10.0 ng/ml and Gleason score ≤6) was 85%, compared to 65% for those with intermediate prognosis (one of the prognostic indicators with a higher value) and 35% for the group with unfavorable prognosis (two or more indicators with higher values) (p < 0.001). PSA relapse-free survival was significantly improved in patients with intermediate and unfavorable prognosis receiving ≤75.6 Gy (p < 0.05). A positive biopsy at ≤2.5 years after 3D-CRT was observed in only 1/15 (7%) of patients receiving 81.0 Gy, compared with 12/25 (48%) after 75.6 Gy, 19/42 (45%) after 70.2 Gy, and 13/23 (57%) after 64.8 Gy (p < 0.05). Conclusions: The data provide evidence for a significant effect of dose escalation on the response of human prostate cancer to irradiation and defines new standards for curative radiotherapy in this disease.
Keywords: adult; cancer survival; controlled study; human tissue; treatment outcome; aged; aged, 80 and over; middle aged; major clinical study; clinical trial; cancer recurrence; cancer radiotherapy; radiation dose; chemotherapy, adjuvant; follow up; prostate specific antigen; radiotherapy dosage; biopsy; prostate cancer; prostate-specific antigen; prostatic neoplasms; prostate biopsy; androgen antagonists; radiation injuries; regression analysis; conformal radiotherapy; radiotherapy, computer-assisted; dose escalation; humans; prognosis; human; male; priority journal; article
Journal Title: International Journal of Radiation Oncology, Biology, Physics
Volume: 41
Issue: 3
ISSN: 0360-3016
Publisher: Elsevier Inc.  
Date Published: 1998-06-01
Start Page: 491
End Page: 500
Language: English
DOI: 10.1016/s0360-3016(98)00091-1
PUBMED: 9635694
PROVIDER: scopus
Notes: Article -- Export Date: 12 December 2016 -- Source: Scopus
Citation Impact
MSK Authors
  1. Venkatraman Ennapadam Seshan
    310 Seshan
  2. Zvi Fuks
    383 Fuks
  3. Michael J Zelefsky
    670 Zelefsky
  4. Paul B Gaudin
    57 Gaudin
  5. Steven A Leibel
    250 Leibel
  6. Gerald J Kutcher
    90 Kutcher
  7. Victor Reuter
    1068 Reuter
  8. C Clifton Ling
    330 Ling
  9. William R Fair
    268 Fair