TNM Classification for Prostate Cancer

The clinical staging of prostate cancer was devised from the American Joint Committee on Cancer (AJCC) tumor, node, metastasis (TNM) system.^[1]Risk stratification is based on the clinical stage as well as the following pretreatment parameters:

Digital rectal examination (DRE) findings
Prostate-specific antigen (PSA) value
Biopsy findings
Imaging study results

Pathological staging is determined following prostatectomy and depends on factors such as tumor burden, status of surgical margins, extracapsular disease, and seminal vesicle and pelvic lymph node involvement. Pathological staging is a more accurate measure of the extent of disease and allows for better prediction of outcomes.^[2]

The TNM classification for prostate cancer is provided below.^[3]

Table 1. TNM Classification for Prostate Cancer (Open Table in a new window)

Primary tumor (T)
Clinical (cT)
TX	Primary tumor cannot be assessed
T0	No evidence of primary tumor
T1	Clinically inapparent tumor not palpable or visible by imaging
T1a	Tumor incidental histologic finding in ≤5% of tissue resected (at time of transurethral resection of the prostate [TURP])
T1b	Tumor incidental histologic finding in >5% of tissue resected (at time of TURP)
T1c	Tumor identified by needle biopsy (because of elevated prostate specific antigen [PSA] level)
T2	Tumor confined within prostate (Note: tumors found in 1 or both lobes by needle biopsy but not palpable on DRE or reliably visible by imaging are classified as T1c)
T2a	Tumor involves one-half of 1 lobe or less
T2b	Tumor involves more than one-half of 1 lobe but not both lobes
T2c	Tumor involves both lobes
T3	Tumor extends through the prostatic capsule (Note: invasion into the prostatic apex, or into—but not beyond—the prostatic capsule is classified as T2
T3a	Extracapsular extension (unilateral or bilateral)
T3b	Tumor invading seminal vesicle(s)
T4	Tumor fixed or invades adjacent structures other than seminal vesicles (eg, bladder, levator muscles, and/or pelvic wall)
Pathologic (pT)*
pT2	Organ confined
pT3	Extraprostatic extension
pT3a	Extraprostatic extension or microscopic invasion of the bladder neck**
pT3b	Seminal vesicle invasion
pT4	Tumor is fixed or invades adjacent structures other than the seminal vesicles (eg, bladder, rectum)
There is no pathologic T1 classification. *Positive surgical margin should be indicated by an R1 descriptor (residual microscopic disease).
Regional lymph nodes (N)
Clinical (cN)
NX	Regional lymph nodes were not assessed
N0	No regional lymph node metastasis
N1	Metastasis in regional lymph node(s)
Pathologic (pN)
pNX	Regional nodes not sampled
pN0	No positive regional nodes
pN1	Metastases in regional nodes(s)
Distant metastasis (M)*
M0	No distant metastasis
M1	Distant metastasis
M1a	Nonregional lymph nodes(s)
M1b	Bone(s)
M1c	Other site(s) with or without bone disease
*If more than 1 site of metastasis is present, use the most advanced category.

Histopathologic Grade for Prostate Cancer

An additional factor influencing prognosis is histopathologic grading. Tissue obtained from a needle biopsy or a prostatectomy is graded using the Gleason Grading System. Gleason grades range from 1 to 5. Each specimen is assigned two grades based on the most common and second most common pattern. These numerical values are added to calculate the Gleason Score.

Table 2. Gleason Score (Open Table in a new window)

Histopathologic grade (G)
GX	Gleason score cannot be assessed
Gleason ≤6	Well differentiated (slight anaplasia)
Gleason 7	Moderately differentiated (moderate anaplasia)
Gleason 8-10	Poorly differentiated or undifferentiated (marked anaplasia)

The 8th edition of the AJCC Cancer Staging Manual took effect on January 1, 2018. A major change is that tumor grading now involves the Gleason Score, as well as the grade group.^[4]

Table 3. Grade Group (Open Table in a new window)

Grade Group	Gleason Score	Gleason Pattern(s)
1	≤6	≤3 + 3
2	7	3 + 4
3	7	4 + 3
4	8	4 + 4 (3+5/5+3)
5	9 or 10	4 + 5, 5 + 4, 5 + 5

Risk Stratification

Prostate cancer risk stratification is based on groups defined by D’Amico et al in 1998. This system has been adopted by the National Comprehensive Cancer Network (NCCN) and is used widely in clinical practice when making decisions regarding treatment and/or active surveillance.^{[3, 5]}

Table 4. Anatomic stage/prognostic groups (Open Table in a new window)

Stage*	T	N	M	PSA	Grade Group
I	cT1a-c, cT2a	N0	M0	< 10 ng/ml	1
I	pT2	N0	M0	< 10 ng/ml	1
IIA	cT1a-c, cT2a	N0	M0	≥10, < 20 ng/ml	1
	pT2	N0	M0	≥10, < 20 ng/ml	1
	cT2b-c	N0	M0	< 20 ng/ml	1
IIB	T1-2	N0	M0	< 20 ng/ml	2
IIC	T1-2	N0	M0	< 20 ng/ml	3
IIC	T1-2	N0	M0	< 20 ng/ml	4
IIIA	T1-2	N0	M0	≥20 ng/ml	1-4
IIIB	T3-4	N0	M0	Any	1-4
IIIC	Any	N0	M0	Any	5
IVA	Any	N1	M0	Any	Any
IVB	Any	Any	M1	Any	Any
*If PSA or Gleason is not available, grouping should be determined by T stage and/or either PSA or Gleason, as available.

See Prostate Cancer: Diagnosis and Staging, a Critical Images slideshow, to help determine the best diagnostic approach for this potentially deadly disease.

Also see the Advanced Prostate Cancer: Signs of Metastatic Disease slideshow for help identifying the signs of metastatic disease.

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Table 1. TNM Classification for Prostate Cancer

Primary tumor (T)
Clinical (cT)
TX	Primary tumor cannot be assessed
T0	No evidence of primary tumor
T1	Clinically inapparent tumor not palpable or visible by imaging
T1a	Tumor incidental histologic finding in ≤5% of tissue resected (at time of transurethral resection of the prostate [TURP])
T1b	Tumor incidental histologic finding in >5% of tissue resected (at time of TURP)
T1c	Tumor identified by needle biopsy (because of elevated prostate specific antigen [PSA] level)
T2	Tumor confined within prostate (Note: tumors found in 1 or both lobes by needle biopsy but not palpable on DRE or reliably visible by imaging are classified as T1c)
T2a	Tumor involves one-half of 1 lobe or less
T2b	Tumor involves more than one-half of 1 lobe but not both lobes
T2c	Tumor involves both lobes
T3	Tumor extends through the prostatic capsule (Note: invasion into the prostatic apex, or into—but not beyond—the prostatic capsule is classified as T2
T3a	Extracapsular extension (unilateral or bilateral)
T3b	Tumor invading seminal vesicle(s)
T4	Tumor fixed or invades adjacent structures other than seminal vesicles (eg, bladder, levator muscles, and/or pelvic wall)
Pathologic (pT)*
pT2	Organ confined
pT3	Extraprostatic extension
pT3a	Extraprostatic extension or microscopic invasion of the bladder neck**
pT3b	Seminal vesicle invasion
pT4	Tumor is fixed or invades adjacent structures other than the seminal vesicles (eg, bladder, rectum)
There is no pathologic T1 classification. *Positive surgical margin should be indicated by an R1 descriptor (residual microscopic disease).
Regional lymph nodes (N)
Clinical (cN)
NX	Regional lymph nodes were not assessed
N0	No regional lymph node metastasis
N1	Metastasis in regional lymph node(s)
Pathologic (pN)
pNX	Regional nodes not sampled
pN0	No positive regional nodes
pN1	Metastases in regional nodes(s)
Distant metastasis (M)*
M0	No distant metastasis
M1	Distant metastasis
M1a	Nonregional lymph nodes(s)
M1b	Bone(s)
M1c	Other site(s) with or without bone disease
*If more than 1 site of metastasis is present, use the most advanced category.

Table 2. Gleason Score

Histopathologic grade (G)
GX	Gleason score cannot be assessed
Gleason ≤6	Well differentiated (slight anaplasia)
Gleason 7	Moderately differentiated (moderate anaplasia)
Gleason 8-10	Poorly differentiated or undifferentiated (marked anaplasia)

Table 3. Grade Group

Grade Group	Gleason Score	Gleason Pattern(s)
1	≤6	≤3 + 3
2	7	3 + 4
3	7	4 + 3
4	8	4 + 4 (3+5/5+3)
5	9 or 10	4 + 5, 5 + 4, 5 + 5

Table 4. Anatomic stage/prognostic groups

Stage*	T	N	M	PSA	Grade Group
I	cT1a-c, cT2a	N0	M0	< 10 ng/ml	1
I	pT2	N0	M0	< 10 ng/ml	1
IIA	cT1a-c, cT2a	N0	M0	≥10, < 20 ng/ml	1
	pT2	N0	M0	≥10, < 20 ng/ml	1
	cT2b-c	N0	M0	< 20 ng/ml	1
IIB	T1-2	N0	M0	< 20 ng/ml	2
IIC	T1-2	N0	M0	< 20 ng/ml	3
IIC	T1-2	N0	M0	< 20 ng/ml	4
IIIA	T1-2	N0	M0	≥20 ng/ml	1-4
IIIB	T3-4	N0	M0	Any	1-4
IIIC	Any	N0	M0	Any	5
IVA	Any	N1	M0	Any	Any
IVB	Any	Any	M1	Any	Any
*If PSA or Gleason is not available, grouping should be determined by T stage and/or either PSA or Gleason, as available.

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Author

Natasza M Posielski, MD Resident Physician, Department of Urology, University of Wisconsin Hospital and Clinics

Natasza M Posielski, MD is a member of the following medical societies: American Urological Association

Disclosure: Nothing to disclose.

Coauthor(s)

Kyle A Richards, MD, FACS Assistant Professor, Department of Urology, University of Wisconsin School of Medicine and Public Health; Chief of Urology, Division of Urology, William S Middleton Memorial Veterans Hospital

Kyle A Richards, MD, FACS is a member of the following medical societies: Alpha Omega Alpha, American College of Surgeons, American Urological Association

Disclosure: Nothing to disclose.

Specialty Editor Board

Mary L Windle, PharmD Adjunct Associate Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Nothing to disclose.

Christopher D Braden, DO Hematologist/Oncologist, Chancellor Center for Oncology at Deaconess Hospital; Medical Director, Deaconess Hospital Outpatient Infusion Centers; Chairman, Deaconess Hospital Cancer Committee

Christopher D Braden, DO is a member of the following medical societies: American Society of Clinical Oncology, American Society of Hematology

Disclosure: Nothing to disclose.

Chief Editor

E Jason Abel, MD Associate Professor of Urologic Oncology, Department of Urology, Associate Professor of Radiology (Affiliate Appointment), Department of Radiology, University of Wisconsin School of Medicine and Public Health; Attending Urologist, William S Middleton Memorial Veterans Hospital

E Jason Abel, MD is a member of the following medical societies: American Medical Association, American Society of Clinical Oncology, American Urological Association, Harris County Medical Society, Kidney Cancer Association, Society for Basic Urologic Research, Society of Urologic Oncology, Texas Medical Association

Disclosure: Nothing to disclose.

Additional Contributors

Reza Ghavamian, MD Professor of Clinical Urology, Albert Einstein College of Medicine; Director of Urologic Oncology, Director of Minimally Invasive and Robotic Urologic Surgery, Montefiore Medical Center

Reza Ghavamian, MD is a member of the following medical societies: American Urological Association, Society of Urologic Oncology

Disclosure: Nothing to disclose.