November 29, 2015
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Anal Cancer (cont.)

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Anal cancer staging

Staging defines the extent of the primary cancerous tumor as well as the presence or absence and extent or spread of the cancer. This staging classification helps the patient's doctors to decide on the best approach to treatment. Staging also helps to estimate the patient's likelihood of survival or prognosis. Finally, it allows doctors who treat these diseases to more accurately compare the results of treatment using various techniques. Such comparisons require that the doctors treat the same extent of cancer from the outset to make their conclusions valid.

Staging techniques include direct visualization and measurement of the cancer and imaging techniques which can include standard X-rays as well as, ultrasound, CAT scan, MRI, and PET scans.

By convention, the stage of the cancer is described using the TNM system as described by the International Union Against Cancer and in the AJCC Cancer Staging Manual. T describes the extent of the tumor. N denotes the presence, or absence, and extent of lymph node metastases. M refers to the presence or absence of distant metastases. Anal cancer stages are as follows:

  • TX: Primary tumor cannot be assessed
  • T0: No evidence of primary tumor
  • T1s: Carcinoma in situ (for example, Bowen's disease, high grade squamous intraepithelial lesion, and anal intraepithelial neoplasia II to III)
  • T1: Tumor less than or equal to 2 cm in greatest dimension
  • T2: Tumor greater than 2 cm but less than 5 cm in greatest dimension
  • T3: Tumor greater than 5 cm in greatest dimension
  • T4: Tumor of any size which invades adjacent organ(s), for example, vagina, urethra, bladder
  • NX: Regional lymph nodes cannot be assessed
  • N0: No regional lymph node metastases
  • N1: Metastases present in perirectal lymph node(s)
  • N2: Metastases in unilateral internal iliac and/or inguinal lymph node(s)
  • N3: Metastases in perirectal and inguinal lymph nodes and/or bilateral internal iliac and/or inguinal lymph nodes
  • M0: No distant metastases
  • M1: Distant metastases present

Consequently, stages can be written in detail as shown in the examples below with the cancer stage increasing in aggressiveness as the stages progress from 0 to IV:

  • 0: T1sN0M0
  • I: T1N0M0
  • II: T2N0M0, T3N0M0
  • IIIA: T13N1M0
  • IIIB: T4N1M0, Any T, N2, or N3M0
  • IV: Any T, Any N, M1
Medically Reviewed by a Doctor on 10/13/2015



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