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Cancer Screening

Colon, Prostate & Breast Cancer Screening

‘Screening’ for a disease means looking for it based on your age, or gender, rather than because you are having problems or symptoms.  There are two cancers we can screen for in men when they turn 50: Colon Cancer and Prostate Cancer.  For women, the two cancers are Colon and Breast.

Based on information from the US Preventative Services Taskforce, we hope this discussion helps you make decisions that are best for you and your family. 


Colon Cancer Screening:  Your colon is the last few feet of your GI tract. 

Colon cancer screening is an easy topic: cancer of the colon is common, most colon cancers are deadly, and screening is clearly beneficial.

There are few symptoms of early colon cancer: later people can have stool changes with bleeding, weight loss, or abdominal pain. 

We’d like to find every case of colon cancer there is, and find it early, while it’s still a little ‘polyp’ sticking off the side of your colon.  Found early, colon cancers are easy to treat and cure.

Our screening tool for colon cancer is most often the colonoscopy.  You ‘clean yourself out’ the day before by drinking medicine that empties your bowels, and we look at your entire colon using a ‘scope’ inserted in your bottom.  Colonoscopy is very accurate, and misses <5% of problem lesions.  The major risk of colonoscopy is ‘perforation’, poking a whole through the side of your colon, which happens in 1:500-1000 cases.  (There are other options for colon cancer that are considered equally good options, including annual lab tests that look for blood in your stool.)

If a polyp is found, it is removed at that time.  If the pathologist says your polyp was pre-cancerous, cancerous, we’ve diagnosed and cured you at the same time, and we know to bring you back sooner to take another look since you are a person at higher risk for cancer.  If your test is fine, we generally recommend a repeat in 10 years.

Colon cancer screening works.  When we look at millions of cases over decades of screening, we clearly save lives and reduce disease with colon cancer screening.  So the American Cancer Society and the US Preventative Services Taskforce say that all patients should screen for colon cancer, starting at 50, and usually stopping at 75.


Prostate Cancer:  The prostate is a peach-sized organ in the urinary tract, between the bladder and penis. 

Prostates get bigger as men age, causing difficulties like delay starting urination and weak stream.  These symptoms have nothing to do with prostate cancer, which generally has no symptoms until late in its course. 

Prostate cancer is the most common cancer found in men, and is the third most common cause of death from cancer.  The percent chance that a man already has prostate cancer is roughly equal to his age.  If we look for prostate cancer, we find it in 10% of men. 

But prostate cancers usually are slow-growing, ‘smoldering’ tumors that you’ll never know are there. And prostate cancers that kill men are most likely to do so at an old age.  Aggressive prostate cancers that threaten a man earlier are much less common, and tend to be so deadly that it makes little difference when we find them.

So we don’t want to find all prostate cancers: we wish we could find only the extremely rare ones that would actually cause harm AND could be stopped if found early. 

Our screening tool for prostate cancer is the ‘PSA’ blood test, commonly paired with a rectal exam.  The PSA unfortunately has only 50:50 accuracy, with 10% ‘false positive’ results and many ‘false negatives’.        

If your PSA is abnormal, a urologist will likely biopsy your prostate, examining cells from several locations. 

·         If the biopsy comes back negative, you could simply have a cancer where the needle didn’t go; 

·         If the biopsy finds an aggressive cancer, we unfortunately have little success in treating those cancers, regardless of when they are found; 

·         If the urologist says: “you have one of these very common, slow-growing tumors”, the best advice is usually to do nothing other than bring you back in a year to monitor it. 

And if that’s where things stop, we haven’t done any harm.  But patients often tell their families, Google prostate cancer and lay in bed worrying about it.  85% of these men are back at the urologist’s shortly wanting it fixed.  The urologist obliges by destroying or removing part of the prostate, leaving 20% of men wearing diapers for life, and 30% needing something more than Viagra for erections.

After decades of screening millions of men for prostate cancer, we can’t demonstrate that we’ve saved lives by doing so.  US studies found no reduction in prostate cancer deaths from screening, and European studies found that screening reduced deaths by 1 per 1,000 men screened.  Nor can we show that treating prostate cancer caused more men to be alive a decade later than if we’d left it alone. 

So all the large organizations either say “do not screen for prostate cancer” (the American Academy of Family Practice and the US Preventative Services Taskforce), or have a detailed conversation before screening (the American Cancer Society) and let the patient decide.

·         If you’re the kind of person that says, “if there’s a problem I want to know it, and I want to fix it, regardless of the benefit or outcome”, then screen for prostate cancer;

·         If you’re the kind who says, “given the low risk of ever having a problem from prostate cancer, the high likelihood of finding a cancer if I go looking, the lack of benefit in diagnosing both benign and aggressive cancers, and the high likelihood of creating health problems if I go looking”, then don’t screen at all;

·         If you are a brave man, you have nothing to lose by screening.  If we identify what appears to be one of these common, slow-growing tumors and you watch it annually and otherwise never give it a thought, we will have done you no harm.


Breast Screening:  Breast tissue extends from your breasts themselves, to your shoulders and underarms.

Breast cancer is a common cancer, with an average lifetime risk of 12%.  Risk factors include family history, and the number of years you have been having periods, so women who began menstruating earlier, or never had children, have increased risk.  You can calculate your risk for breast cancer with the Breast Cancer Risk Assessment Tool (commonly known as the Gail Model), found on the internet at

There are few symptoms of early breast cancer.  Women with advanced disease may note dimpling of the skin, bloody nipple discharge, or a lump that in the same spot over several months and menstrual cycles.

The screening tool for breast cancer is the mammogram, often paired with a breast exam by your provider (though the physical exam is not the important part).

The harms resulting from screening for include:

·         ‘psychological harm’ that comes from being unnecessarily alarmed;

·         inconvenience from false-positive screening results;

·         radiation exposure (from radiologic tests), although a minor concern, is also a consideration.

·         unnecessary imaging tests and biopsies in women without cancer;

·         treatment of cancer that you’d never have found or been harmed by in your lifetime (‘over-diagnosis’);

·         unnecessary early treatment of breast cancer that would someday have become apparent but would not have shortened your life;

False-positive results are more common in women 40 to 49 years of age, while over-diagnosis is a greater concern for older women.  False positives are a natural part of any screening test: since screening tries never to miss anything, it is bound to find lots of spots that aren’t really there, or never likely to be a problem. 

Screening by risk groups:

·         Mammograms are proven to be of benefit in women 50 to 75, performed every other year.  The strongest evidence for the benefit is in women 60 to 69 years of age. 

·         For women 40 to 49 years of age, screening is an option after considering the risks and benefits.  

·         Screening over the age of 75 is an individual decision, keeping your life expectancy, and goals of care in mind. There is no evidence of benefit from screening in this age group.

·         For women with an estimated lifetime breast cancer risk of more than 20% or who have a BRCA mutation, screening should begin at either at age 25, or 5-10 years younger than the earliest breast cancer diagnosed in the family.