Prostate cancer: less is better

Good news for men with prostate cancer. A new approach means less treatment and less worry.
The Canadian Cancer Society says this year, more than 24 thousand  men will be diagnosed with prostate cancer.
And that number's expected to double within fifteen years  -- leaving more and more Canadian men wondering what to do in terms of treatment. A study just published in the Canadian Medical Association Journal provides some reassuring advice. 

When men are diagnosed with prostate cancer, the doctor sends a biopsy of the cancer to the pathologist to see how malignant or serious the cancer is.  The good news is that up to 50% of all newly diagnosed prostate cancers are what doctors call low grade or mild. These cancers grow slowly and have a very small likelihood of causing death. In the past, men with low-grade prostate cancer had surgery to remove it as well as radiation and medications.  

Now, a growing number of doctors don't treat the cancer.  Instead, they do something called active surveillance; they watch these men closely, do periodic PSA blood tests, rectal examinations to examine the prostate and when necessary more biopsies. If the cancer becomes more malignant, that's when they start treatment.

And that's what this study recommends as the way forward for treating prostate cancer - after looking at how effective it could be. Here's the background behind the change in approach. In 2014, two studies( here and here) published in JAMA Internal Medicine found that a significant number of Americans with low-grade cancers had surgery, radiation and hormone therapy treatments that are mainstays of aggressive cancer only. The men with low-grade cancers who got these treatments had no improvement in survival.  

Worse than that, the treatments cause potential side effects.  Surgery and radiation can cause loss of bowel and bladder control, erectile dysfunction and occasionally even death. Hormone treatments can cause muscle weakness and increase the risk of diabetes and heart disease.  Treating low risk prostate cancer aggressively is one of the most egregious examples of what's known as over-diagnosis and over-treatment.

Researchers in Ottawa studied 477 men with prostate cancer referred to the Regional Prostate Cancer Assessment Clinic between 2008 and 2013. Of those, 210 had active surveillance and 244 had early aggressive treatment for prostate cancer.  All of the patients who received early treatment had highly malignant prostate cancers.  Of the 210 with low-grade cancers managed with active surveillance, 62 were found eventually to have more aggressive cancer and had their cancers treated. At the five-year mark, nearly 60% of those with low risk cancer were alive and well and still getting active surveillance.  

What they weren't getting were unnecessary treatments  saving patients harm and saving the system time and money.

Critics say active surveillance is only as effective as the doctor is vigilant.  They say it's possible to miss the mild cancer that becomes more aggressive. The doctor is dependent on doing repeat biopsies to detect a more serious cancer. It's possible to take a biopsy that misses the most malignant part. Then, there's the psychological burden of living with prostate cancer without active treatment. Some men and their partners become paralyzed with fear because the cancer hasn't been removed.

That said, in the study in CMAJ and others, the anxiety of the patient was not the deciding factor in whether the patient had active surveillance or aggressive treatment.  That means patients and their families were willing to accept the uncertainty of living with-instead of getting rid of the cancer.

Guidelines from Canada and elsewhere no longer recommend routine screening for men at average risk of prostate cancer.  For them, PSA testing and digital rectal examinations have not been shown to reduce mortality from prostate cancer enough to justify the cost and the risk of over-treatment.  Men over 50 should discuss screening with their doctor.  Men at higher risk of prostate cancer because of a family history of prostate cancer or breast cancer should talk to their doctor about screening around age 40 to 45.  Although we need more evidence, for them, screening may offer some benefit.  

The bottom line is that men who are willing to accept a substantial risk of harm associated with treatment in return for a small reduction in mortality might reasonably choose to be screened. But if you are low risk, you can rest easy knowing you're being watched. 

Dr. Brian Goldman is an emergency physician and host of White Coat, Black Art on CBC Radio One.


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