The TNM system has replaced the old Robson staging system regarding staging of kidney cancer. T stands for criteria regarding the primary tumor( T1 to T4) and corresponds with stage I to IV in the old staging system.
N stands for lymph nodes and M for distant metastases. Here is a brief simplified description of the TNM classification for kidney cancer. As with other cancers, it is important to accurately determine the cancer stage before cancer treatment in order to know what the treatment achieved after a certain period of time. Where diagnoses are attempted without CT scanning and other tests, hidden metastases locally or in distant locations (that were missed) worsen the cancer survival rates. In series where patients were staged at the time of surgery according to histology results the 5-year and 10-year survival rates for stage I and II kidney cancer patients were 80% or higher.
With stage III there are often systemic micro-metastases already seeded in the body, which is why theoretically it is difficult to get higher survival rates in his stage unless newer therapies can be developed that control metastases.
Staging for kidney cancer
Stage
I : small tumor, minimal distortion of architecture of kidney
II : large tumor, deformity of kidney +/- enlargement
III : cancer reaching tissues around kidney +/- veins, lymph node metastases present
IV : cancer invading muscles, bowel, distant metastases
With stage IV this problem is so overwhelming that even the best combined therapies could not improve 5-year survival above 20%. The limiting factor appears to be the metabolic change from the overwhelming cancer cell load as well as the paralyzing effect on the immune system.
References:
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2. Cancer: Principles&Practice of Oncology. 5th edition, volume 1. Edited by Vincent T. DeVita, Jr. et al. Lippincott-Raven Publ., Philadelphia,PA, 1997. Chapter on Cancer of the kidney and ureter.
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