Normal development and prognosis for urothelial cancer depends on the malignancy grade of the tumor (WHO grade).
Grade 1 tumor
Grade 1 tumors have a weak propensity to invade and metastasize, but grow exophytically and can become very large. The tumor can grow so large that it can fill the entire urinary bladder and obstruct urine from the ureters and bladder. The tumor can also be localized to the renal pelvis or ureters and obstruct these organs. This type of tumor usually causes periodic macrohematuria. A grade 1 tumor can change malignancy grade and become more agressive.
Grade 2 tumor
Grade 2 tumors can grow exfoliative and cause symptoms from the growing tumor occuing the bladder. All grade 2 tumors will infiltrate into the wall of the organ of origin, penetrate this, and infiltrate into neighboring organs (the pelvic wall (bladder), and retroperitoneal tissue (ureter/renal pelvis)). If left untreated, they will metastasize to lymph nodes and other organs (lungs, bone, liver, and others).
Grade 3 or undifferentiated tumor
Grade 3 tumors rarely grow exfoliative. They are highly malignant, grow infiltrative, and metastasize early.
In addition to WHO grading, the prognosis for patients with urothelial cancer depends on the TNM stage and whether the primary disease is multifocal.
Superficial (pT ≤ 1)
Superficial urothelial cancer has a 30% chance of developing muscle infiltration within 5-10 years after primary treatment, all WHO grades combined. The frequency of recurrence is about 70% after treatment. This requires resources for follow-up and detect recurrences as early as possible. Primary multifocal disease has a higher chance of recurrence than primary solitary disease.
Prognostic factors for recurrence are:
- high histological malignancy grade
- multiplicity of the tumors
- presence of carcinoma in situ/dysplasia in surrounding urothelium
Muscle infiltrating (pT ≥ 2)
Five year survival after radical treatment is 40–60%, and has not changed significantly in later years. The use of preoperative radiation or chemotherapy has not changed these numbers.
The prognosis depends on:
- the T-stage
- tumor size > 7 cm
- tumor invasion in small blood and lymphatic vessels
- high malignancy grade (WHO grade 3)
Five-year relative survival for patients with urothelial cancer, in percent, during the diagnosis period 1974–2013.
Source: Cancer Registry of Norway