Why is a digital exam used for prostate cancer – 03/14/2023 – Equilibrium

The digital rectal exam to determine the existence of prostate cancer is now being questioned. An international panel of experts recently suggested replacing “active surveillance” with magnetic resonance imaging.

This news can be celebrated as the end of an intrusive medical exam, thanks to the advancement of technology. But what exactly is a digital rectal exam and what are the consequences of replacing it?

The rectal exam consists of checking the rectal wall, made by a doctor, who inserts a finger through the patient’s anus. This gives the professional access to the prostate gland, helping him to find signs of cancer.

This type of test was the only method available to check for prostate cancer until 1986, when the prostate-specific antigen (PSA) test appeared, made with blood extracted from the patient.

The rectal exam can also be used to detect other types of cancer, such as rectal and anal cancer. It can also be used to check for retained stool in people with constipation and other circumstances.

In women, the digital rectal exam is used to check for cancer, including the spread of ovarian cancer.

If performed correctly, the exam shouldn’t be too uncomfortable. And privacy and good communication can go a long way in overcoming any awkwardness.

All medical students learn to take the exam. Many have been told for generations that when examining patients, “If you don’t put your finger in, you might end up screwing up.”

The prostate is a walnut-sized gland. It sits in the pelvis and surrounds the urethra as it exits the bladder. Conveniently, it lies to the side of the rectum and is easily felt by the finger during examination.

If it is inflamed, as in the case of prostatitis, it will be tender. And when there is benign prostate growth, which happens in middle age and causes a backflow of urine, the prostate will appear swollen.

In the case of prostate cancer, the surface may be irregular and the texture firm to the touch. But it is very common for prostate cancer to go undetected in the early stages of the disease.

The end of gloves

The UK medical school system rightly places great emphasis on learning good clinical skills.

Excessive dependence on technology is considered a possible waste of the scarce resources available. Also, apparently, patients like to think that their doctors are experienced in clinical diagnosis.

But there are times when technology offers greater precision in finding diseases, especially when they are in their early stages.

MRI provides detailed images of body structures. Unlike X-rays and CT scans, it does not use ionizing radiation (related to an increased risk of cancer) and is considered safe. It is also effective for detecting prostate cancer at an early stage and for “surveillance” (monitoring) of the disease.

On the other hand, MRI is expensive, the machines are large in volume, consume a lot of energy and are usually restricted to hospitals. All this limits its use.

There is a blood test – the aforementioned PSA test – which is used to signal prostate disease, but it is not specific for cancer.

When used in combination with digital rectal examination, it helps detect cases. But PSA levels are elevated after the digital rectal exam, which makes the timing of the exam difficult. The blood needs to be drawn at another appointment.

What, then, is the role of the digital rectal exam in the diagnosis of prostate cancer?

I believe it is still needed. Prostate cancer easily spreads to the bones and it is not uncommon for the undiagnosed disease to manifest itself in the form of back pain when the cancer has already spread to the vertebrae.

And, if suspected, any positive rectal exam results may lead to earlier diagnosis and fewer delays in starting the correct treatment.

Gloves again then?

The digital rectal exam works a little better for rectal cancer. If the tumor is in an accessible location for the examining physician’s finger, it is possible to detect it in up to 76% of cases.

For constipation, finding stool in the rectum can eliminate the expense and radiation exposure of modern investigations, which have replaced the X-ray of the abdomen with the radiation-intensive CT scan.

Is the rectal exam dead? I don’t think so. It is an inexpensive test that provides useful information when performed and interpreted correctly.

*Stephen Hughes is Professor of Medicine at Anglia Ruskin University in the United Kingdom.

This article was originally published on the academic news site The Conversation and republished under a Creative Commons license.