The threat of
cancer is daunting for many and health care providers as well as the general
public have long held beliefs that screening for the presence of cancer will
aid in early detection as well as reduce mortality due to cancer. A startling
new study by Dr Vinay Prasad and colleagues has found that screening for cancers
may not be all that good.
involves checking for cancers when the patient shows no symptoms of the disease. This, doctors believe will -
- Aid in detecting cancers at an early stage.
- Be effective in treatment procedures.
- Reduce cancer mortality rates.
However, this study published in The British Medical Journal
(January, 2016) dispels
these commonly held beliefs.
‘Cancer screening procedures should be restricted to high-risk groups, considering the harm associated with them.’
Concerns Raised by the Study:
- Cancer screening may decrease mortality that is disease specific but does not affect overall mortality
- Deaths are associated with the negative impact of cancer screening procedures
- False positive tests
- Increased attention, diagnosis and
cancer treatment afforded to tumors that are harmless
Colon Cancer Screening
Study at Minnesota
Colorectal cancer i.e the cancer affecting the lower digestive system comprising of colon and rectum is the most common cancers affecting both men and women, Stool tests and endoscopic tests are used in the screening of
The study by Moayyedi and Achkar showed that
- 128 deaths due to colon cancer per 10,000 in the screened group
- 192 deaths due to colon cancer in
the control (non-screened) group
- Overall mortality - 7111 deaths per 10,000 in the screened group and 7109 deaths per 10,000 in the control
Prostate cancer is one of the most common forms of cancer among males. The limiting factors raised by Dr Prasad and colleagues concerning prostate cancer include -
- Prostate cancer screening is based on detecting prostate specific antigen (PSA) in the blood stream. The detection of this antigen can lead to false positive results. This leads to one million prostate biopsies every year.
- The surgery for acquiring prostate biopsies requires hospitalization with
the risk of death.
- Men who have been diagnosed with prostate cancer after cancer screening methods are more likely to -
- Have a heart attack within one year of diagnosis
- Commit suicide due to the diagnosis
- Die of treatment associated
mortalities even before symptoms set in
Other studies also show that prostate screening is not essential for kidney transplant
patients too as it affects the transplantation procedure
and does more harm than good.
The study also
showed the skewed impressions about cancer screening among women who underwent
mammography, PSA screening
or even cervical smear test.
- 68% of women believed that
mammography would decrease their risk of
developing breast cancer
- 62% thought that the risk of
breast cancer was reduced by half
The deaths associated with cancer screening procedures
could merely result in the trading of one cause of death for another. In other words, the harm associated with cancer screening could make the entire process futile, coupled with the increased time, effort and money spent on availing the screening procedures.
associated with screening procedures should dissuade people from taking up
screening unless they are in the high-risk group. For example, heavy smokers should be screened for lung cancer
while it may make little
sense to carry out lung screening
procedures for people who have never smoked or associated with low air pollution levels.
In the future,
better screening procedures that reduce the risks associated with screening and
more intensive studies that focused more on non-cancer mortalities between the
screened and the non-screened groups would benefit the cause of cancer care and