How can screen­ing be harm­ful?

Prince Albert Daily Herald - - NEWS - Keith Roach

DEAR DR. ROACH: Ev­ery ar­ti­cle I have read about prostate screen­ing fails to de­fine “screen­ing.” I had thought of screen­ing as the PSA blood test and/or the dig­i­tal exam. But since you and every­one else de­scribe the screen­ing it­self as pos­si­bly harm­ful, it must con­sist of more than I had in mind. I would ap­pre­ci­ate an ex­pla­na­tion. -- R.G.

AN­SWER: A screen­ing test is one that is done to di­ag­nose a con­di­tion in some­one who has no symp­toms of the con­di­tion. Strictly speak­ing, much of gath­er­ing your med­i­cal his­tory in­volves ask­ing screen­ing ques­tions (such as, “Do you have any short­ness of breath?”); the phys­i­cal exam of­ten qual­i­fies as a screen­ing test; and there are many blood and ra­di­ol­ogy tests that are used to screen.

A good screen­ing test is safe and in­ex­pen­sive. A con­di­tion ap­pro­pri­ate for screen­ing is one that is com­mon enough to make screen­ing worth­while, se­ri­ous enough to mat­ter and has bet­ter out­comes if treated early, com­pared with treat­ing after symp­toms de­velop.

For prostate cancer in par­tic­u­lar, the screen­ing tests them­selves aren’t the prob­lem: A tube of blood or a phys­i­cal exam may be un­pleas­ant, but not re­ally harm­ful. The harm can come when the screen­ing test turns pos­i­tive. An ab­nor­mal PSA test of­ten leads to a biopsy, which it­self can oc­ca­sion­ally cause harm. Then again, the real harm comes after the biopsy, when cancer can be di­ag­nosed. Some can­cers are very in­do­lent, mean­ing they grow slowly and are un­likely to cause prob­lems in the fore­see­able fu­ture. Some men wish to re­move any type of cancer, no mat­ter how small the risk of growth, and in­stead will choose to un­dergo treat­ment rather than take a wait-and-see ap­proach. It is these treat­ments -- usu­ally surgery or ra­di­a­tion -- that have the po­ten­tial for harm, as many men de­velop side ef­fects that im­pair their qual­ity of life, es­pe­cially sex­ual side ef­fects and in­con­ti­nence of urine.

There are two ways to avoid pos­si­ble harm from a screen­ing test: Don’t do one (which some groups rec­om­mend when it comes to prostate cancer screen­ing), or do the test only if you are pre­pared to be ra­tio­nal about the find­ings. That means you can get the ben­e­fit of pos­si­bly find­ing and treat­ing an ag­gres­sive cancer early, but can avoid un­nec­es­sary treat­ment for a low-risk or very-low-risk tu­mor. It isn’t al­ways easy to be ra­tio­nal about these choices, so it’s im­por­tant to know ahead of time what the pos­si­bil­i­ties are.

DEAR DR. ROACH: Over two decades ago, my pri­mary physi­cian put me on plain niacin tablets each morn­ing and each evening when he dis­cov­ered that I had a choles­terol of 382. In the time since and after that doc re­tired, new docs have put me on bet­ter and bet­ter choles­terol medicine, the lat­est be­ing 40-mg tabs of ro­su­vas­tatin (Crestor) ev­ery evening. The re­sult has been ex­cel­lent: My choles­terol read­ing was last at 170 and had been as low as 130. None of my docs nor I have no­ticed any bad re­ac­tions from the niacin. My docs, though they of­ten won­der about it, as­sume it ap­par­ently has pos­i­tive ef­fects.

AN­SWER: I wrote re­cently about the fact that niacin can raise blood sugar, but I’m afraid I didn’t get across my main point: We lower choles­terol not be­cause we like see­ing a good num­ber, but be­cause we want to lower the risk of heart dis­ease. Un­for­tu­nately, the most re­cent stud­ies show that although niacin makes the num­bers bet­ter, it prob­a­bly does not re­duce the risk of heart dis­ease more than tak­ing ro­su­vas­tatin (or a sim­i­lar statin drug) by it­self. The niacin may not be caus­ing you side ef­fects, but I’m not at all sure that it’s re­ally help­ing you.

Dr. Roach re­grets that he is un­able to an­swer in­di­vid­ual let­ters, but will in­cor­po­rate them in the col­umn when­ever pos­si­ble. Read­ers may email ques­tions to ToYourGoodHealth@med.cor­nell.edu or re­quest an or­der form of avail­able health news­let­ters at 628 Vir­ginia Dr., Or­lando, FL 32803. Health news­let­ters may be or­dered from www.rb­ma­mall.com.

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