[back] Medical tests
THE DOWNSIDE OF SCREENING FOR CANCER
by Ralph W. Moss, Ph.D.
It is a modern day mantra that screening for cancer offers the best chance of catching the disease early and thereby reducing deaths. But is this really true? Does screening really reduce cancer mortality? Are there any drawbacks to widespread routine screening in populations not at heightened risk for cancer?
Anyone pondering these difficult questions would do well to consider the letter written to the editor of the journal Radiology by William J. Casarella, MD, of the Department of Radiology, Emory University School of Medicine.
During a routine colonoscopy, Dr. Casarella's vigilant radiologist observed a suspicious-looking area on one kidney, another on the liver, and several small lung nodules as well.
After undergoing further extensive tests including CT and PET scans, a liver biopsy and thoracoscopy (a visual examination of the interior of the chest cavity, necessitating deliberate collapsing of his right lung), Dr. Casarella, in his own words, "woke up in the recovery room after 5 hours, with a chest tube, a Foley [bladder] catheter, a subclavian central venous catheter, a nasal oxygen catheter, an epidural catheter, and arterial catheter, subcutaneously administered heparin, a constant infusion of prophylactic antibiotics and patient-controlled analgesia with intravenously administered narcotics" (Casarella, 2002).
A further 2 weeks of rest at home were needed before the pain became tolerable. After 5 weeks, Dr. Casarella was able to return to work. The total cost of these procedures exceeded $50,000. And Dr. Casarella's various suspicious lesions all turned out to be entirely benign.
Screening for cancer is a two-edged sword. While early detection does indisputably mean that the lesions detected are easier to treat, there is considerable evidence to suggest that not all lesions detected through screening are uniformly menacing. Many would never progress to invasive cancer at all. The trouble is that currently there is no way of telling which are menacing and which are innocent except by further invasive tests such as surgical biopsy.