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Correction
February 27, 2008

Incorrect Data Reported in Text and Figure in: Comparison of Conventional-Dose vs High-Dose Conformal Radiation Therapy in Clinically Localized Adenocarcinoma of the Prostate: A Randomized Controlled Trial

JAMA. 2008;299(8):899-900. doi:10.1001/jama.299.8.899

Incorrect Data Reported in Text and Figure: In the Original Contribution entitled “Comparison of Conventional-Dose vs High-Dose Conformal Radiation Therapy in Clinically Localized Adenocarcinoma of the Prostate: A Randomized Controlled Trial” published in the September 14, 2005, issue of JAMA (2005;294[10]:1233-1239), data were incorrectly reported. In the “Results” section of the Abstract on page 1233, the first and second sentences should have read as follows: “The proportions of men free from biochemical failure at 5 years were 78.8% (95% confidence interval, 73.1%-84.6%) for conventional-dose and 91.3% (95% confidence interval, 87.2%-95.4%) for high-dose therapy (P < .001), a 59% reduction in the risk of failure. The advantage to high-dose therapy was statistically significant in the low-risk subgroup (risk reduction, 84% [P < .001]).”

In the “Biochemical Outcome” section on page 1236, the first through third paragraphs should have read as follows:

“In the conventional-dose group, 79.2% had a PSA nadir below 1.0 ng/mL, and 41.6% had a nadir below 0.5 ng/mL. In the high-dose group those proportions were 86.6% and 58.8%, respectively. The difference between the proportions with a PSA nadir below 0.5 ng/mL was significant (P = .007). Median time to nadir was 27.0 months after conventional-dose and 39.6 months after high-dose therapy.

The 5-year freedom from biochemical failure was 78.8% (95% confidence interval [CI], 73.1%-84.6%) for conventional-dose and 91.3% (95% CI, 87.2%-95.4%) for high-dose therapy (P<.001) (Figure 2). This represents a 59% reduction in the risk of failure at 5 years. This advantage for high-dose therapy was seen when those with low-risk disease (PSA level <10 ng/mL, stage T1b-T2a tumors, or Gleason score ≤6; n = 227 [58% of total]) were examined alone (82.6% in the conventional-dose group and 97.3% in the high-dose group; 84% risk reduction; P<.001) (Figure 3). The reduction was not significant for the higher-risk patients taken overall (74.1% vs 81.8%; 30% risk reduction; P = .10). When the higher-risk patients were broken out into contemporary intermediate- and high-risk subgroups,20 significance emerged for the intermediate-risk subgroup (74.5% vs 87.4%;51% risk reduction; P = .02) but was not observed in the small number (n = 33) of high-risk patients (P = .49).

The backdating used in the ASTRO definition of biochemical failure may affect the timing and rate of failure,13 so we performed an analysis without it. The differences between the groups persisted and remained significant (Figure 2). At 5 years it was 81.3% vs 93.2% for conventional-dose and high-dose therapy, respectively (P<.001). Significant differences also persisted when men were divided into low-risk (84.7% vs 97.8%, P<.001) and intermediate-risk (79.1% vs 90.9%, P = .02) subgroups, although again there was no difference seen in the very small number of men with high-risk disease.”

In the fourth paragraph of the “Biochemical Outcome” section, the value reported as P = .40 should have been reported as P = .11. On page 1237, Figure 2 and Figure 3 should have appeared as shown here. In the “Comment” section on page 1238, the fifth and sixth sentences of the second paragraph should have read “The advantage to higher radiation dose was as clear and significant for those with low-risk disease as it was for those with intermediate risk, and this represents the novel finding of the trial. The advantage was slightly greater for the low-risk group than for the intermediate-risk group (84% reduction in risk of failure at 5 years, compared with 51%), perhaps reflecting the fact that these men are more likely to have locally confined disease and thus are more likely to benefit from an improved local therapy.” See also related letter in this issue.

Figure 2. Freedom From Biochemical Failure (Increasing PSA Level) Following Either Conventional-Dose (70.2 GyE) or High-Dose (79.2 GyE) Conformal Radiation Therapy
Figure 2. Freedom From Biochemical Failure (Increasing PSA Level) Following Either Conventional-Dose (70.2 GyE) or High-Dose (79.2 GyE) Conformal Radiation Therapy

A, Analysis of outcome using American Society for Therapeutic Radiology and Oncology criteria, in which biochemical failure occurs on the third increase but is backdated to a point midway between the last nonincreasing value and the first increase. B, Same analysis as in A, but without backdating. GyE indicates gray equivalents (see “Methods” section); PSA, prostate-specific antigen. Error bars indicate 95% confidence intervals.

Figure 3. Freedom From Biochemical Failure (ASTRO Definition) Following Either Conventional-Dose (70.2 GyE) or High-Dose (79.2 GyE) Conformal Radiation Therapy
Figure 3. Freedom From Biochemical Failure (ASTRO Definition) Following Either Conventional-Dose (70.2
GyE) or High-Dose (79.2 GyE) Conformal Radiation Therapy

Analysis of these early cases is by risk subgroup. Low-risk patients have prostate-specific antigen level <10 ng/mL, stage ≤T2a tumors, and Gleason score ≤6. ASTRO indicates American Society for Therapeutic Radiology and Oncology; GyE, gray equivalents (see “Methods” section).

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