How is prostate cancer diagnosed ?
Digital rectal examination essential
The digital rectal examination (DRE) is essential as part of the diagnostic process before conducting a PSA test. A suspicious DRE finding warrants further examinations, even if the PSA level falls within the usual range (≤ 3 to 4 ng/ml).
If the PSA level is elevated after a DRE, it is recommended to recheck the PSA level after a delay of one to two weeks (as per AFU recommendations).
This is because any manipulation near the prostate can artificially increase the PSA level. If the PSA level remains elevated, the risk of prostate cancer increases with higher PSA levels.
Expert perspective
When the PSA level is low, the doctor may closely monitor its annual evolution (PSA velocity): an annual increase of more than 2 ng/ml is of significant prognostic value and warrants enhanced surveillance.
- PSA between 3 and 7 ng/ml: 25% risk of cancer
- PSA between 5 and 30 ng/ml: 65% risk of cancer
- PSA between 30 and 100 ng/ml: 95% risk of cancer
- PSA between 100 and 1000 ng/ml: 95% risk of cancer
The importance of MRI
In cases where prostate cancer is suspected, it is currently recommended to undergo a prostate MRI (Magnetic Resonance Imaging) before considering prostate biopsies.
If the MRI results are negative and the patient is at low risk (PSA <0.15 ng/ml), the patient will undergo clinical and biological surveillance with potentially additional MRIs.
If the MRI results are uncertain or positive, prostate biopsies will be necessary.
Examination of biopsies of precision
💡 DID YOU KNOW ?
Prostate biopsies aim to obtain prostate tissue for examination by a pathologist, a specialist in tissue and cell analysis.
The pathologist determines whether the prostate cells are normal, benign, or cancerous. After consultation with a urologist, biopsies are performed under local or general anesthesia.
A fine needle is inserted through the rectum or perineum (the area between the anus and genitals) to reach the prostate. Ultrasound guidance is used to target the prostate area, and approximately a dozen samples are taken. This procedure, which lasts between 15 to 20 minutes, is not painful due to anesthesia but carries some risks such as infection or local bleeding.
The examination of biopsies by the pathologist will, in the case of cancer, clarify the nature of the tumor cells and classify the cancer. The nature of prostate cancers varies depending on the type of prostate cells that gave rise to the cancer cells and the location within the prostate where the tumor cells originated.
What is the Gleason score ?
Classifications of prostate cancers such as the Gleason score or the ISUP 2016 classification have prognostic value on the disease progression.
Expert perspective
In cases of cancer, a staging assessment will be performed, including an MRI of the pelvis to determine if tumor cells have invaded nearby lymph nodes. Various imaging tests may be conducted to determine the presence of metastases: bone scintigraphy, whole-body MRI, or PET scan (Positron Emission Tomography coupled with a CT scan). The PET scan involves intravenously injecting a radioactive substance that binds to cancerous tissues.
These tests help define the stage of the tumor :
- Stage I and II tumors are localized tumors.
- Stage I cancers cannot be felt during a digital rectal exam. The cancer is localized within the prostate and does not breach the capsule.
- Stage II cancers can be felt during a digital rectal exam. They invade more tissue within the prostate but still do not breach the capsule.
- Stage III cancers are locally advanced: these cancers have spread beyond the capsule to invade nearby tissues but there are no distant metastases.
- Stage IV cancers are metastatic forms: these cancers have spread to lymph nodes or other parts of the body.
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Article updated on Nov 21, 2024
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