Prostate cancer staging and risk group

According to the AJCC: 

Clinical T (cT)

Primary Tumor
TX — Primary tumor cannot be assessed
T0 — No evidence of primary tumor
T1 — Clinically inapparent tumor that is not palpable
T1a — Tumor incidental histologic finding in 5% or less of
tissue resected
T1b — Tumor incidental histologic finding in more than 5%
of tissue resected
T1c — Tumor identified by needle biopsy found in one or both sides,
but not palpable
T2 — Tumor is palpable and confined within prostate
T2a — Tumor involves one-half of one side or less
T2b — Tumor involves more than one-half of one side but
not both sides
T2c — Tumor involves both sides
T3 — Extraprostatic tumor that is not fixed or does not invade
adjacent structures
T3a — Extraprostatic extension (unilateral or bilateral)
T3b — Tumor invades seminal vesicle(s)
T4 — Tumor is fixed or invades adjacent structures other
than seminal vesicles such as external sphincter, rectum,
bladder, levator muscles, and/or pelvic wall.

Pathological T (pT)

T — Primary Tumor
T2 —  Organ confined
T3 — Extraprostatic extension
T3a — Extraprostatic extension (unilateral or bilateral) or microscopic
invasion of bladder neck
T3b — Tumor invades seminal vesicle(s)
T4 — Tumor is fixed or invades adjacent structures other than seminal
vesicles such as external sphincter, rectum, bladder, levator
muscles, and/or pelvic wall
Note: There is no pathological T1 classification.
Note: Positive surgical margin should be indicated by an R1 descriptor, indicating
residual microscopic disease.

N — Regional Lymph Nodes
NX — Regional lymph nodes cannot be assessed
N0 — No positive regional nodes
N1 — Metastases in regional node(s)

M — Distant Metastasis
M0 — No distant metastasis
M1 — Distant metastasis
M1a — Nonregional lymph node(s)
M1b — Bone(s)
M1c — Other site(s) with or without bone disease

According to the NCCN guidelines, 

Very low: 

• Has all of the following:
  • cT1c
  • Grade Group 1
  • PSA <10 ng/mL
  • Fewer than 3 prostate biopsy fragments/cores positive, ≤50%
  cancer in each fragment/coreg
  • PSA density <0.15 ng/mL/g

Low:

Has all of the following but does not qualify for very low risk:
• cT1–cT2a
• Grade Group 1
• PSA <10 ng/mL

Moderate: 

Has all of the
following:
• No high-risk group
features
• No very-high-risk
group features
• Has one or more
intermediate risk
factors (IRFs):
cT2b–cT2c
Grade Group 2
or 3
PSA 10–20 ng/mL

High:

Has no very-high-risk features and has exactly one high-risk
feature:
• cT3a OR
• Grade Group 4 or Grade Group 5 OR
• PSA >20 ng/mL

Very High:

Has at least one of the following:
• cT3b–cT4
• Primary Gleason pattern 5
• 2 or 3 high-risk features
• >4 cores with Grade Group 4 or 5