When we think of cancer, most people know that screening regularly and early diagnosis is key to beating the disease. However, when it comes to prostate cancer it’s not that simple.
Despite being the second leading cause of cancer death in Australian men (after lung cancer), there’s no population-based screening for prostate cancer like there is for other major cancers, such as breast and bowel cancer. The tests that are available – digital rectal exams and the prostate specific antigen (PSA) test – are somewhat controversial because they can lead to overdiagnosis, harmful testing and unnecessary treatment.
Digital rectal exams – which most men associate with a rubber glove, lubrication and a professional examining the rectum for changes in the prostate – aren’t recommended by Cancer Council Australia at the GP level because the tests can pick up noncancerous changes. Instead, it’s recommended they’re only performed if a man has already been diagnosed with cancer.
The PSA test on the other hand looks for specific antigen levels (substances foreign to the body that causes an immune response) in the blood. While prostate cancer can cause these levels to rise, they can also increase because of non-cancerous issues, such as an enlarged prostate, urinary tract infections or benign prostate disease. Many men with a positive PSA reading don’t have prostate cancer, while low readings may also fail to detect if cancer is present.
“What that means is a single test wouldn’t be sufficient for you to suddenly have investigations to see if you’ve got prostate cancer,” Professor Sanchia Aranda, CEO of Cancer Council Australia, tells Starts at 60. “You’d want to know that the test was elevated over a period of time and that it was increasing.”
If a man’s first PSA test returns a positive result, another test is performed a few months later to assess whether PSA levels are increasing. If they are, a biopsy of the prostate would be performed to investigate further.
While early detection and treatment can save lives, prostate cancer is typically a slow-growing cancer – particularly in older men. This means that for some patients, the cancer doesn’t cause harm or symptoms because it never grows enough to become problematic. The biopsy – which is actually what diagnoses cancer – can cause irreversible damage to the prostate, while surgery and treatment to remove the cancer may lead to incontinence, bowel function issues and erectile dysfunction.
“You don’t want to do those biopsies if there’s not a high risk of [the patient] having cancer because it does carry that harm,” Aranda says.
While it was common in the past for men to have their prostate removed if cancer was present, many with a low-risk diagnosis now choose to practice active surveillance – where a health provider monitors the progression of the cancer through regular PSA measurements, digital rectal exams, MRIs and further biopsies. If the cancer shows sign of aggressive growth, a patient can start treatment or undergo surgery.
Findings published in the 2018 annual report of the Movember Prostate Cancer Outcomes Registry – Australia and New Zealand (PCOR-ANZ), found that 69 per cent of men diagnosed with low-risk prostate cancer during 2015 to 2016 went on active surveillance. The remaining 31 per cent of men with low-risk prostate cancer went on to have treatments they may not have needed.
“The reality is if you biopsied the prostate of men in their 80s and 90s, the vast majority would have prostate cancer in them,” Aranda says. “Again, back to that concept of diagnosis, the reason it’s called overdiagnosis is you’re diagnosing cancers that would never have become problematic in the man’s lifetime.”
Other men diagnosed with prostate cancer opt for a process called watchful waiting – where they wait until symptoms appear or the cancer to become problematic before they undergo radiotherapy or hormone treatment. It’s less strict than active surveillance and the aim is to treat symptoms that become problematic, rather that cure cancer.
“They choose to focus on quality of life at the time of their diagnosis and wait and see whether they want to have any of the treatments at a point where the cancer becomes problematic,” Aranda says.
Cancer Council Australia says there is an urgent need for more sophisticated risk assessment and early-detection technology, but until then men have to make do with the available options and work with their doctor to determine the best treatment plan for their particular case.