Prostate Cancer Checks: What Hospitals Do And Why

Prostate cancer is typically detected through a combination of screening tests and physical examinations. The most common screening test is the PSA (prostate-specific antigen) blood test, which measures the level of PSA in the blood. Higher levels of PSA can indicate the presence of prostate cancer or other prostate conditions. In addition to the PSA test, doctors may also perform a digital rectal exam (DRE), where they insert a gloved, lubricated finger into the rectum to feel for any abnormalities in the prostate. If the screening tests or symptoms suggest prostate cancer, further tests, such as a prostate biopsy, may be required for a definitive diagnosis. During a biopsy, small samples of the prostate are removed and examined under a microscope to detect cancerous cells.

Prostate-specific antigen (PSA) blood test

Prostate-specific antigen (PSA) is a protein produced by cells in the prostate gland, both normal and cancerous. PSA is mostly found in semen, but a small amount is also present in the blood. The PSA blood test is used to screen for prostate cancer in men without symptoms and is one of the first tests performed on men who are experiencing symptoms that could be caused by prostate cancer.

The PSA blood test is a simple procedure in which a healthcare provider draws a sample of blood and sends it to a lab for analysis. The test measures the level of PSA in the blood, which is higher in men with prostate cancer or other prostate conditions. However, it is important to note that there is no definitive cutoff point for PSA levels that indicates the presence or absence of prostate cancer. While most men without prostate cancer have PSA levels below 4 ng/mL, a level below 4 does not guarantee the absence of cancer. Men with PSA levels between 4 and 10 have about a 25% chance of having prostate cancer, but many of these cases are low-grade cancers that may not require treatment. If the PSA level is above 10, the likelihood of prostate cancer is over 50%, although some of these cases may still be low-grade.

Interpreting PSA screening results can be challenging due to several factors. Firstly, it is possible to have prostate cancer and still have normal PSA levels. Secondly, many factors can influence PSA levels, so an abnormal result may not necessarily indicate cancer. For example, elevated PSA levels can also suggest an enlarged or inflamed prostate, which requires further testing to determine the underlying cause. Therefore, while the PSA blood test is an important tool for prostate cancer screening, it is not a diagnostic test on its own. If the PSA test results are abnormal, further tests, such as a biopsy, may be recommended to confirm the presence of cancer.

The PSA blood test is often used in conjunction with a digital rectal exam (DRE), where a healthcare provider inserts a gloved, lubricated finger into the rectum to feel the prostate for any abnormalities. Although the DRE is not recommended as a standalone screening test, it can detect cancer in individuals with normal PSA levels. Therefore, healthcare providers often recommend both tests for a more comprehensive evaluation.

Digital rectal exam (DRE)

Digital rectal examination (DRE) is one of the most important tests for the early detection of prostate cancer. The prostate gland is located just in front of the rectum, so a doctor or nurse can feel the prostate through the wall of the back passage (rectum) to check for signs of cancer and see if it is enlarged. This involves inserting a lubricated, gloved finger into the patient's rectum to feel for lumps, enlargements, or areas of hardness that might indicate cancer. The procedure lasts for less than a minute and, while uncomfortable, should cause no pain.

The digital rectal exam can be performed at a GP surgery or a hospital. The patient will be asked to lie on their side on an examination table, with their knees brought up towards their chest. The doctor or nurse will then slide a finger gently into the patient's back passage. They will wear gloves and put some gel on their finger to make the process more comfortable.

The digital rectal exam is often combined with a prostate-specific antigen (PSA) blood test, which measures the level of PSA in the blood. PSA is a protein made by cells in the prostate gland and is mostly found in semen, but a small amount is also present in the blood. The chance of having prostate cancer increases as the PSA level goes up, but there is no set cutoff point that can determine whether a man has prostate cancer. Doctors may use a PSA cutoff point of 4 ng/mL or higher when deciding if further testing is required.

While the PSA test is considered more effective for detecting prostate cancer, the DRE can detect cancer in people with normal PSA levels. Therefore, the two tests are often used in conjunction with each other. However, it is important to note that neither test can confirm a diagnosis of prostate cancer, and further tests such as a biopsy may be required.

Some studies have questioned the efficacy of the DRE in primary care settings, suggesting that it may result in a high number of false positives and unnecessary invasive diagnostic tests. Despite this, the DRE is still frequently used as part of routine prostate cancer screening, especially when combined with the PSA test.

Prostate biopsy

Prostate cancer is typically detected through a screening process that may include a PSA blood test and a digital rectal exam (DRE). However, these screening methods cannot provide a definitive diagnosis of prostate cancer. If the screening results are abnormal, indicating potential signs of cancer, a prostate biopsy is performed to confirm the presence of cancer.

A prostate biopsy involves removing small samples of the prostate for microscopic examination. The core needle biopsy, performed by a urologist, is the primary method used for diagnosing prostate cancer. During the procedure, the doctor visualises the prostate using imaging techniques such as transrectal ultrasound (TRUS), MRI, or a fusion of both.

The biopsy procedure involves the doctor quickly inserting a thin, hollow needle into the prostate, either through the rectal wall or the skin between the scrotum and anus. When the needle is withdrawn, it removes a small cylinder of prostate tissue, referred to as a core sample. Typically, the doctor collects around 12 core samples from different regions of the prostate. Despite the invasive nature of the procedure, it only causes brief discomfort due to the use of a specialised spring-loaded biopsy instrument.

The collected tissue samples are then sent to a laboratory for analysis by a pathologist. This specialist examines the cells to determine if they are cancerous. If cancer is detected, it is then graded and assigned a Gleason score, which indicates the likelihood of the cancer spreading and growing. This comprehensive process of prostate biopsy is crucial for establishing a definitive diagnosis of prostate cancer and guiding subsequent treatment decisions.

Transrectal ultrasound (TRUS)

TRUS is usually performed as an outpatient procedure in a hospital or clinic, and it typically takes 15 to 30 minutes. Patients are asked to lie on their left side with their knees bent towards their chest, as this position is more comfortable and allows for easier insertion of the rectal probe. Before the procedure, patients may be instructed to have an enema to remove any feces or gas from the rectum, which could impede the progress of the probe.

During the procedure, the probe sends sound waves to the prostate gland, and the echoes from normal and abnormal tissue are relayed to the computer. The computer translates these patterns into a video image of the prostate. TRUS can help detect changes in the prostate, including abnormal growths.

In some cases, TRUS may be used to perform a biopsy, where a thin, hollow needle is attached to the transducer. The doctor uses the ultrasound image to guide the needle into the prostate and collect tissue samples from different areas, including any abnormal regions. These samples are then sent to a lab to be tested for cancer cells. TRUS-guided biopsies may have side effects, such as blood in the urine, stool, or semen for several days after the procedure.

Additionally, TRUS can be used to deliver treatments such as high-intensity focused ultrasound (HIFU), which uses ultrasound waves to generate intense heat and destroy abnormal tissue. TRUS plays a crucial role in the detection, diagnosis, and treatment of prostate cancer and related conditions.

Magnetic resonance imaging (MRI)

Multiparametric MRI (Mp-MRI) is an advanced form of imaging that provides anatomical images and information on the function of the prostate gland. It assesses water molecule motion (water diffusion) and blood flow (perfusion imaging) within the prostate, helping doctors distinguish between diseased and healthy tissue. Mp-MRI can help determine whether cancer is present, whether it is aggressive, and whether it has spread beyond the prostate. It can also detect abnormalities that may be obscured by bone with other imaging methods.

The MRI exam may use an endorectal coil, a thin wire covered with a latex balloon, which is placed a short distance into the rectum to generate more detailed images. MR spectroscopy can also be performed to provide additional information on the chemical makeup of cells in the prostate.

MRI has the capability to assess prostate tissue, both functionally and morphologically. However, as a staging tool, it has not shown enough consistency or accuracy for widespread adoption in clinical practice. Nevertheless, recent developments in MRI technology have yielded improved results, with techniques such as T1-weighted images, T2-weighted images, dynamic contrast-enhanced (DCE) T1-weighted images, and MR spectroscopy providing new opportunities to evaluate biological processes.

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