Monday, 12 November 2007

Staging Prostate Cancer

Updated to include a video of an MRI scan. Click on 'MRI' link in Regional Lymph Nodes (N).

The following article is excerpted from PSA Rising - Prostate Cancer Survivor (News, Info & Support) in the hope readers may become more informed. I would encourage all our readers to visit the author's website.


What is Staging?

If prostate cancer has been found by any method, the next step is to see how much of the prostate it takes up and whether it has spread outside the prostate to nearby tissue, lymph nodes, organs and/or bones.

This is called staging the cancer. Your prostate cancer stage is key to your treatment options. Primarily, staging is based on your digital rectal exam (DRE).


Two different systems of staging have been used for prostate cancer.

Today the older ABCD system has largely been replaced by the TNM (Tumor, Nodes, Metastases) system. In addition, two levels of staging are used, clinical and pathologic.

Clinical staging is based on digital exam and any further non-invasive tests necessary to find the extent of the cancer. It affects primary treatment decisions.

Pathologic stage refers to examination of the prostate and any other tissue removed during surgery. Only patients who undergo surgery receive the second level of staging.


The TNM system of staging

Primary tumor (T)

TX: Tumor cannot be assessed.

T1: Doctor is unable to feel the tumor or see it with imaging such as transrectal ultrasound.

T1a: Cancer is found incidentally during a transurethral resection (TURP) for benign prostatic enlargement. Cancer is present in less than 5% of the tissue removed.

T1b: Cancer is found after TURP and is present in more than 5% of the tissue removed.

T1c: Cancer is found by needle biopsy done because of an elevated PSA.

T2: Doctor can feel the tumor when a digital rectal exam (DRE) is performed but the tumor still appears to be confined to the prostate.

T2a: Cancer is found in one half or less of only one side (left or right) of the prostate.

T2b: Cancer is found in more than half of only one side (left or right) of the prostate.

T2c: Cancer is found in both sides of the prostate.

T3: Cancer has begun to spread outside the prostate and may involve the seminal vesicles.

T3a: Cancer extends outside the prostate but not to the seminal vesicles.

T3b: Cancer has spread to the seminal vesicles.

T4: Cancer has spread to tissues next to the prostate (other than the seminal vesicles), such as the sphincter, rectum and/or wall of the pelvis.

T4a: Invades bladder neck, external sphincter, or rectum.

T4b: Invades muscles and/or pelvic wall.


Regional Lymph Nodes (N)

To see if the cancer has spread to the lymph nodes or bones, the doctor may order a CT scan or an MRI of the pelvis and a bone scan.



Sentinel lymph nodes in the pelvis that look suspicious on CT scan or MRI can be examined by fine needle aspiration biopsy method. This is done commonly in breast cancer staging.

NX: Nodes cannot be assessed

N0: No regional node metastasis

N1: Single node metastasis, 2 centimeters (cm) or less at largest point

N2: Single node metastasis, 2 cm to 5 cm at largest point, or multiple nodes, no larger than 5 cm at largest point

N3: Metastasis larger than 5 cm in any node


Distant Metastasis (M)

MX: Metastasis cannot be assessed

M0: No distant metastasis

M1: Distant metastasis

M1a: Distant lymph node(s) involved

M1b: Bone(s) involved

M1c: Other site(s) involved (e.g. liver, lung)


Note on stages that "cannot be assessed."

Patients in whom abnormal digital rectal examinations (DREs) do not match up with their prostate biopsy findings are "clinically unstageable."

To find out what unstageable prostate cancer involves, Wisconsin researchers looked at post-op pathology reports of some 100 patients who were unstageable.

"For these patients pathological staging revealed pT2a cancers in 26%, pT2b in 53%, pT3a in 19%, pT3b and pT0 in 1% of patients." The authors conclude: "Thus, the prevalence of unstageable prostate cancer is low but significant and it can be accurately classified into clinical stage T1c. "Clinical and pathological characteristics of unstageable prostate cancer: analysis of the CaPSURE database. Langenstroer P et al. Medical College of Wisconsin. J Urol. 2005 Jul;174(1):118-20.

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