New research presented at the annual meeting of the American Society of Clinical Oncology revealed that the use of low-dose spiral CT scanning for the early detection of lung cancer is an ineffective screening tool because it produces an unacceptably high rate of false positive tests, leading to a substantial number of risky and invasive diagnostic procedures.
According to the study: "An individual's cumulative probability of at least one false-positive CT scan was 21% after one screen and 33% after two. ... Of those getting a CT false positive, 6.6% had an invasive diagnostic procedure and 1.6% had major surgery."
This means that approximately 2.2% of all patients screened will have an unnecessary invasive diagnostic procedure and about 0.5% of all patients screened will have unnecessary (and risky) major surgery.
The Rest of the Story
These new findings indicate that at the present time, the use of low-dose spiral CT scanning for the early detection of lung cancer is not effective as a screening tool and its use should not be recommended as a screening method.
The findings are in contrast to the assertions of Dr. Claudia Henschke, the researcher from the Weill Cornell Medical College who, as I reported here (post 1; post 2) in March of last year, has been a strong advocate for the use of CT scans as a screening technique for lung cancer.
The rub: Dr. Henschke covered up the fact that her work was funded by a tobacco company, failed to disclose a number of patents related to CT screening for lung cancer, and also failed to disclose royalties received from GE related to the use of CT scanning for the early detection of lung cancer.
To make matters worse, after being forced to properly disclose the financial conflicts of interest, Dr. Henschke and her institution still refused to admit that they had done anything wrong, defending their behavior with an inappropriate, uncompelling, and somewhat misleading excuse statement (post 1; post 2).
In other words, Dr. Henschke has a vested financial interest in showing that CT scans are an effective lung cancer screening tool, has been pushing that position, and pushed that position in the medical literature without disclosing her financial interest in pushing such a position.
This is a serious, and unfortunate, example of a severe conflict of interest and a resulting ethical breach of conduct by an an anti-smoking researcher.
The importance of the new research findings is that they demonstrate how off the mark Dr. Henschke was with her conclusions and how potentially damaging her apparently biased recommendations were.
The failure of Dr. Henschke and her institution to: (1) disclose the relevant funding source and conflicts of interest; and (2) to admit that they erred in failing to make those disclosures represent what in my mind are serious breaches of ethical conduct. Those breaches of conduct have been made ever so much worse by the recent news that CT scanning yields huge numbers of false positive results, causing unnecessary risk, pain, and suffering among human subjects.
In my view, every subject who is entered into clinical trials in which Dr. Henschke is an investigator and/or in which Cornell Medical College is involved should be informed of the relevant conflicts of interest as part of the consent procedure. The patients should also be informed of the high frequency of serious adverse effects from the study intervention, including the high possibility that they will require unnecessary invasive diagnostic procedures and/or major surgery. They should also be informed that there is currently no evidence that the screening will have any benefit for them or for the study population as a whole.
The failure of Dr. Henschke and Cornell Medical College to readily disclose the conflicts of interest is particularly egregious because of the high risk of harm to subjects in this research. We are talking not only about scientific harm caused by bias due to financial interests; we are also talking about real and serious harm to humans that is made much worse, and much less excusable, by the existence of the financial conflicts of interest.