CHANGES IN MEDICAL THINKING COME SLOWLY
CHANGES IN MEDICAL THINKING COME SLOWLY
Blog: On mammography and PSA tests, November 2009
In October, 2009, an ongoing controversy in cancer screening surfaced. Top level people at the American Cancer Society and a lead article in the Journal of the American Medical Association took a negative slant on screening with both mammography and the PSA blood test for prostate cancer. Analysis of results over several decades showed an increase in the numbers of less invasive cancers diagnosed but no decline in death rates from the diseases in general.
The problem is that not all breast and prostate cancers behave the same. Some are highly aggressive and spread when very, very small, before any means available can find them. Others behave as if they are not cancerous at all, some even disappearing by themselves with no treatment. The highly malignant forms can develop so rapidly they are usually not detected with either mammography or a PSA. The slowly developing forms represent little threat to life. Screening leads to over diagnosis and many people being treated who would be better off not treated at all. In addition there are complications from the unnecessary procedures applied to false positives.
This may explain why the death rate from breast cancer is just about the same now as in 1958 when my own mother was diagnosed. In 1958 the best information I could find was that the five year survival rate was about 80%. Current figures from the American Cancer Society web site for 2009 show 192,370 newly diagnosed cases and 40,170 deaths, or a survival rate of 79.2%.
I recently read some promotional information from the breast cancer people. Their literature stated that if detected very early breast cancer had a survival rate of 98%. This statistical manipulation increases donations to anti-cancer organizations but can’t be accurate given the above numbers. The only way they can get such an inflated figure is if they are counting mostly people with very early changes who would not die of the disease if left untreated.
When this information hit the major media outlets panic ensued. One recommendation that changed was for women to delay having mammograms until age 50. These recommendations came from strictly scientific studies that had no connection with health insurance plans being debated in congress. Nonetheless some conservative commentators saw in this a sinister conspiracy to kill off women who might develop breast cancer between 40 and 50, thus reducing costs of health bills before congress.
.
Blog: On mammography and PSA tests, November 2009
In October, 2009, an ongoing controversy in cancer screening surfaced. Top level people at the American Cancer Society and a lead article in the Journal of the American Medical Association took a negative slant on screening with both mammography and the PSA blood test for prostate cancer. Analysis of results over several decades showed an increase in the numbers of less invasive cancers diagnosed but no decline in death rates from the diseases in general.
The problem is that not all breast and prostate cancers behave the same. Some are highly aggressive and spread when very, very small, before any means available can find them. Others behave as if they are not cancerous at all, some even disappearing by themselves with no treatment. The highly malignant forms can develop so rapidly they are usually not detected with either mammography or a PSA. The slowly developing forms represent little threat to life. Screening leads to over diagnosis and many people being treated who would be better off not treated at all. In addition there are complications from the unnecessary procedures applied to false positives.
This may explain why the death rate from breast cancer is just about the same now as in 1958 when my own mother was diagnosed. In 1958 the best information I could find was that the five year survival rate was about 80%. Current figures from the American Cancer Society web site for 2009 show 192,370 newly diagnosed cases and 40,170 deaths, or a survival rate of 79.2%.
I recently read some promotional information from the breast cancer people. Their literature stated that if detected very early breast cancer had a survival rate of 98%. This statistical manipulation increases donations to anti-cancer organizations but can’t be accurate given the above numbers. The only way they can get such an inflated figure is if they are counting mostly people with very early changes who would not die of the disease if left untreated.
When this information hit the major media outlets panic ensued. One recommendation that changed was for women to delay having mammograms until age 50. These recommendations came from strictly scientific studies that had no connection with health insurance plans being debated in congress. Nonetheless some conservative commentators saw in this a sinister conspiracy to kill off women who might develop breast cancer between 40 and 50, thus reducing costs of health bills before congress.
.
posted by Dr. Charles McGee at
1:20 PM
|
0 Comments
