Changing Trends in the National Practice for External Beam Radiotherapy for Clinically Localized Prostate Cancer: The 1999 Patterns of Care Survey for Prostate Cancer
Reviewer: Heather Jones, MD
Last Modified: October 7, 2002
Presenter: M.J. Zelefsky
Presenter's Affiliation: Memorial Sloan-Kettering Cancer Center, New York, NY, USA
Type of Session: Scientific
This study is an evaluation of the changing trends in external beam radiotherapy (EBRT) delivery practice for clinically localized prostate cancer based on the 1999 survey from the American College of Radiology National Patterns of Care Study (PCS) compared to the 1994 PCS.
Materials and Methods
- The 1999 PCS survey included 443 patients surveyed from 47 institutions treated between 1/1999 and 12/1999.
- The majority of the population was treated with EBRT only 320 (72%) and the rest with of the population was treated with brachytherapy + EBRT, 123 (28%). Only the EBRT group is included in this evaluation
- The study population was categorized as favorable, intermediate and unfavorable groups base on PSA, Gleason Score and T stage (PSA <10, Gleason Score <6 and T stage < T3); the presence of one or more of these features classified patients into intermediate and unfavorable risk groups, respectively.
- 40% were considered favorable, 39% were considered intermediate and 21% were considered unfavorable.
- The following trends in clinical practice were analyzed according to these prognostic risk groupings and other variables and compared to the prior survey from 1994: the use of androgen deprivation therapy in combination with EBRT, higher prescription dose levels, and the administration of elective whole pelvic radiation (WPR).
- The median age in this group was 72 years (range: 49-86 years).
- The clinical stages in these patients were as follows: TX-6%, T0-6%, T1-43%, T2-34%, T3-6%, T4-0.3% and unknown in 6%.
- The pre-treatment PSA levels were as follows: (<4)-11%, (4-10)-57%, (11-20)-20%, and (>20)-12%.
- The Gleason score distribution was (2-6)-53%, (7)-29% and (8-10) -18%.
- Large portion of patients were treated with androgen deprivation therapy (ADT) in conjunction with EBRT, (50%) of patients
- The use of ADT was significantly more prevalent among treated patients in the 1999 survey compared to the 1994 survey (50% versus 9%, p < 0.0001).
- In a multivariate analysis PSA >10 and Gleason scores of 7-10 were the only significant variables influencing ADT usage in the 1999 survey.
- Conformal radiotherapy was reported to be used in 85% of treated patients; with a median prescription dose of 70.45 Gy (range: 27-79.2 Gy).
- Compared to the 1994 survey, a greater percentage of patients were treated with higher radiation doses (>72 Gy, 1999-48% vs. 1994-3%, p < 0.0001).
- In the 1999 survey the percentage of patients with favorable, intermediate and unfavorable tumors treated to doses >72 Gy were 48%, 43% and 56%, respectively, compared to 3%, 3% and 4%, respectively, in the 1994 survey.
- Compared to the 1994 survey, there was a significant increase in brachytherapy (28% vs. 3% p<0.001).
- There was no significant difference observed for the use of WPR in the 1999 compared to the 1994 survey (1999-28% vs. 1994-33%, p = 0.17).
In the 1999 PCS there is a significant increase in the use of androgen deprivation therapy in high-risk patients. Also, we see the use of a higher radiation doses, especially for intermediate and high-risk patients. Most of the high-risk patients were not treated with elective whole pelvis radiation.
The evaluation of the 1999 patterns of care survey clearly reflects the growing acceptance of recent clinical trial results. As recent clinical trials have demonstrated the efficacy of dose escalation and adjuvant hormonal therapy, the patterns of care survey reflects the penetrance into clinical practice. The high percentage of favorable risk patients treated with high dose EBRT is greater than expected. This serves to remind us to be mindful of an all-inclusive application of a treatment arm from a positive clinical trial.
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