Knowing how deep the tumor has penetrated is essential. Treatments depend on the stage and grade of the cancer. Staging, along with the knowing the aggressiveness or "grade" of the tumor (see below) will give an indication of the growth or spread. The "T"' stage refers to clinical staging only, meaning what can be seen with current diagnostic tools. Bladder cancer is notoriously understaged- up to 40% of the time.
The "P" stage is the best determination of actual stage but can only be assessed by examining the bladder after its removal, thus the doctors refer to "P" stage, or pathological stage, only after radical cystectomy has been perfomed.
The American Joint Committee on Cancer (AJCC) has designated staging by TNM classification to define bladder cancer:
T=Tumor, N+Nodes involved, M=metastasis
TX Primary tumor cannot be assessed
T0 No evidence of primary tumor
Ta Noninvasive papillary carcinoma
Tis Carcinoma in situ: "flat tumor"; CIS is always considered high grade, high risk in a blc diagnosis
T1 Tumor invades subepithelial connective tissue [T1 is sometimes divided further into a, b and c]
T2 Tumor invades muscle
T2a -Tumor invades superficial muscle (inner half)
T2b -Tumor invades deep muscle (outer half)
T3 Tumor invades perivesical tissue (fat surrounding the bladder)
T4 Tumor invades any of the following: prostate, uterus, vagina, pelvic wall, or abdominal wall.
T4a -Tumor invades the prostate, uterus, vagina
T4b -Tumor invades the pelvic wall, abdominal wall
N0 - no cancer in any lymph nodes
N1 - one affected lymph node smaller than 2cm across
N2 - one affected lymph node larger than 2cm, but smaller than 5cm. 1 or more may be affected
N3 - at least one affected lymph node larger than 5cm across
Stage 0 -Tis or Ta, N0, M0
Stage I -T1, N0, M0
Stage II -T2a, N0, M0 or T2b, N0, M0
Stage III -T3a, N0, M0 or T3b, N0, M0 or T4a, N0, M0
Stage IV -T4b, N0, M0, any T, N1-N3, M0, or any T, any N, M1
Tumor grade appears to correlate significantly with the natural history of transitional cell carcinoma. The higher the grade of the diagnosis, the higher the incidence of death from the disease within two years. Thus grade III would be considered an aggressive form of cancer. Some doctors rate with scale of I-IV but this is rarely used anymore.
The World Health Organization (WHO) classification recognizes three grades of urothelial/transitional cell cancer.
Grade 1 or I represents well-differentiated papillary tumors with limited abnormalities.
Grade 2 or II represents tumors of intermediary risk
Grade 3 or III a marked increase in the cell layers and cell size with obvious abnormalities
Note: Carcinoma in situ (CIS) -a flat type of tumor that usally shows up alongside other tumor types- is considered aggressive/grade III in all diagnoses of bladder cancer.