We're unable to sign you in at this time. Please try again in a few minutes.
We were able to sign you in, but your subscription(s) could not be found. Please try again in a few minutes.
There may be a problem with your account. Please contact the AMA Service Center to resolve this issue.
Contact the AMA Service Center:
Telephone: 1 (800) 262-2350 or 1 (312) 670-7827  *   Email: subscriptions@jamanetwork.com
Error Message ......
Letters |

Correction: Inaccurate Analysis and Results in a Study of Radiation Therapy in Adenocarcinoma of the Prostate

Anthony L. Zietman, MD
JAMA. 2008;299(8):898-899. doi:10.1001/jama.299.8.898-c.
Text Size: A A A
Published online


To the Editor: I am writing to inform the editors and readers of JAMA of errors in a study of conventional-dose vs high-dose conformal radiation therapy in clinically localized prostate cancer, published in the September 14, 2005, issue of JAMA, for which I was principal investigator.1

These errors were uncovered in the process of working on a series of secondary analyses for which access to the raw data was needed. All of the original data had been collected, stored, and analyzed by the statistics department of the American College of Radiology (ACR). For one secondary analysis, the raw data were obtained from the ACR and the original Kaplan-Meier analysis of cancer-free survival was rerun. This outcome had been defined as freedom from 3 successive increases in the level of prostate-specific antigen (PSA). We were unable to reproduce the curves reported in the JAMA article and brought this to the attention of the ACR statisticians. They traced the problem to an error in the definition of PSA failure coded in the computer program. Although the primary outcome of the study was biochemical failure defined as 3 successive increases (as indicated in the “Methods” section of the article), the computer code identified any 3 increases as biochemical failure. This erroneously identified additional patients as “failures” along with those correctly classified.


Sign in

Purchase Options

• Buy this article
• Subscribe to the journal
• Rent this article ?

First Page Preview

View Large
First page PDF preview




Also Meets CME requirements for:
Browse CME for all U.S. States
Accreditation Information
The American Medical Association is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. The AMA designates this journal-based CME activity for a maximum of 1 AMA PRA Category 1 CreditTM per course. Physicians should claim only the credit commensurate with the extent of their participation in the activity. Physicians who complete the CME course and score at least 80% correct on the quiz are eligible for AMA PRA Category 1 CreditTM.
Note: You must get at least of the answers correct to pass this quiz.
Please click the checkbox indicating that you have read the full article in order to submit your answers.
Your answers have been saved for later.
You have not filled in all the answers to complete this quiz
The following questions were not answered:
Sorry, you have unsuccessfully completed this CME quiz with a score of
The following questions were not answered correctly:
Commitment to Change (optional):
Indicate what change(s) you will implement in your practice, if any, based on this CME course.
Your quiz results:
The filled radio buttons indicate your responses. The preferred responses are highlighted
For CME Course: A Proposed Model for Initial Assessment and Management of Acute Heart Failure Syndromes
Indicate what changes(s) you will implement in your practice, if any, based on this CME course.


Some tools below are only available to our subscribers or users with an online account.

0 Citations

Sign in

Purchase Options

• Buy this article
• Subscribe to the journal
• Rent this article ?

Related Content

Customize your page view by dragging & repositioning the boxes below.