Case Review Form

      * Denotes required field.

      Title

      * First Name

      * Last Name

      * Email Address

      * Phone Number

      Cell Phone Number

      Office Phone Number

      Street Address

      Apartment/Suite

      City

      State

      Zip Code

      Please provide the best method and times to contact you:

      Date of birth of injured person
      (mm-dd-yyyy):

      Name of drug:

      Date you started taking the drug (mm-yyyy):

      Date you stopped taking the drug (mm-yyyy):

      Please describe any side effects:

      Other Info:

      No Yes, I agree to the Parker & Waichman LLP disclaimers.Click here to review all.

      Yes, I would like to receive the Parker & Waichman LLP monthly newsletter, InjuryAlert.

      please do not fill out the field below.

Are Observational Cancer Drugs Studies Biased?

Filed April 22nd, 2008 amy

Are observational studies of really all that reliable? A recent study published in the American Cancer Society’s peer-review journal “Cancer” concludes that certain biases may exist in observational studies that compare outcomes of different cancer therapies, making the results questionable. Their research is suggesting that these observational studies should be better designed to minimize inaccuracies, as well as to include more thorough information.

Unlike clinical trials, which are considered golden, observational studies which do not involve randomization but where available data are nonetheless analyzed to make treatment comparisons, have also been used to provide information on how well patients respond to particular drugs. According to ScienceDaily, many investigators perform these types of studies by analyzing data from the Surveillance, Epidemiology and End Results (SEER) Tumor Registry, a national population-based cancer registry that collects cancer-related information.

To determine the accuracy of observational studies on cancer treatments, Dr. Sharon H. Giordano of the University of Texas MD Anderson Cancer Center in Houston and her colleagues compared the effectiveness of different cancer therapies in terms of prolonging survival in patients, using data from the SEER registry. They presented several examples, including re-analyses of previously published data. In all cases, they came up with improbable results, indicating how easy it is to generate questionable results when conducting an observational study.

In their first analysis, the researchers looked at data on a hormone therapy called androgen deprivation in men with stage III prostate cancer. Randomized clinical trials have shown that androgen deprivation can improve survival in these patients. When the investigators analyzed data from the SEER registry of more than 5,000 men, they found that men treated with androgen deprivation actually had a higher risk of death from prostate cancer than men who did not receive the therapy.

Dr. Giordano and her team next re-analyzed data from a previously published study of more than 43,000 men with localized prostate cancer who were treated compared with men who were not treated. Like the original study, the researchers’ analysis revealed that men who were treated for prostate cancer experienced lower mortality rates. However, they also found that in many cases, the cause of death was due to something other than prostate cancer, such as diabetes or pneumonia.

Finally, the investigators re-analyzed data from a previously published study on the effects of fluorouracil-based chemotherapy for colon cancer. They came to the same conclusion as the original research study–that chemotherapy for node positive colon cancer is associated with improved survival. However, they found that the link between the treatment and survival was strongest for non-cancer deaths, which presumably are not related.

The authors attributed the improbable results found in their three analyses to selection biases when patients are treated. For example, selection bias occurs when patients with poorer prognoses are more likely to receive a more efficacious drug, or when patients with better underlying health are more likely to receive a more toxic treatment because they are more likely to tolerate it.

The authors concluded that their findings “suggest that the results of observational studies of treatment outcomes should be viewed with caution.” They recommended that analyses of observational data should at a minimum attempt to segregate patient outcomes into those that could possibly be due to the treatments vs. those that could not. Many observational studies on cancer treatments only report death rates from all causes and do not specify cancer-related deaths.

Be Sociable, Share!

Comments are closed.

Click Here Now, to Have an Attorney Answer Your
Medicinal Drug Injuries Questions
No Cost - No Obligation!