The prognosis of rectal carcinoma is most accurately predicted by: (AIIMS Nov 2011)
|A||Size of growth|
|D||Site of the growth|
a. Staging may be defined as the process by which objective data are assembled to try to define the state of progression of the disease.
b. At the present time, the stage of the tumor is assessed by indicating the depth of penetration of the tumor into the bowel wall (T stage), the extent of lymph node involvement (N stage), and the presence or absence of distant metastases (M stage).
c. Dukes' stage A cancer is confined to the bowel wall. Stage B cancer penetrates the bowel wall, and stage C cancer indicates lymph node metastases.
d. There are four possible stages of colorectal cancer within the AJCC system. In stage I, there is no lymph node metastasis, and the tumor is either T1 or T2 (up to muscularis propria).
e. Patients who undergo appropriate resection of T stage 1 colon cancer have a 5-year survival rate of about 90%. Stage II is now subdivided into IIA (if the primary tumor is T3) and IIB (for T4 lesions), with no lymph node metastasis.
f. The 5-year survival rate for patients with stage II colon cancer treated by appropriate surgical resection is about 75%.
g. Stage III cancer is characterized by lymph node metastasis and is now subdivided into IIIA (T1-T2, N1, M0), IIIB (T3-T4, N1, M0), and IIIC (any T, N2, M0). In the latest version of the staging system (2003), smooth metastatic nodules in the pericolic or perirectal fat are considered lymph node metastasis and should be included in N staging.
h. The survival for stage III cancer treated by surgery alone has been about 50%.
i. Distant metastatic disease (stage IV) carries a poor prognosis, with a 5-year survival rate of less than 5%.