Stages of cervical cancer

The staging system for cervical cancer depends on the size of the tumor, the extent of the tumor into cell layers (stromal invasion), and spread to other areas of the body (metastasis). Staging of cervical cancer has been done by the American Joint Committee on Cancer (AJCC) and the Federation Internationale de Gynecologie et d'Obstetrique (FIGO). The two classification systems are very similar.

AJCC TNM staging classification¹

The primary tumor (T) is staged in the following way:

• TX. Primary tumor cannot be assessed.
• T0. No primary tumor is seen.
• Tis (Carcinoma in situ). The cancer is found only in one area of the cervix and only very near surface of the cervix. This type of cervical cancer is called carcinoma in situ.
• T1. Cervical carcinoma is only found in the uterus.
  • T1a. Invasive carcinoma diagnosed by microscopy with stromal invasion is no more than 5mm in depth and 7mm wide.
    • T1a1. Stromal invasion is 3mm or less in depth and 7mm or less in width. This is also called microinvasive carcinoma.
    • T1a2. Stromal invasion is between 3mm and 5mm in depth and 7mm or less in width.
  • T1b. Visible tumor only on the cervix or microscopic tumor is larger than 5 mm in depth and 7 mm wide.
    • T1b1. Visible tumor is 4cm or less in size.
    • T1b2. Visible tumor is more than 4cm in size.
• T2. Cancer invades beyond the uterus but not to the pelvic wall or the lower third of the vagina.
  • T2a. Tumor does not involve the connective tissue (parametrium) around the uterus.
  • T2b. Tumor does extend into the parametrium around the uterus.
• T3. The tumor extends to the pelvic wall and/or involves the lower third of the vagina, and/or blocks a kidney so urine cannot flow out, or causes a nonfunctioning kidney.
  • T3a. Tumor involves lower third of vagina but no extension into the pelvic wall.
  • T3b. Tumor extends to pelvic wall and/or causes a blocked kidney or a nonfunctioning kidney.
• T4. Tumor invades the lining of the bladder or rectum, and/or extends beyond the pelvis.
  • M1. Distant metastasis: The cancer has spread to distant parts of the body.

After the tumor (T) is staged, the TNM system stages lymph node involvement (N) to help determine the treatment options at each stage. Lymph node involvement is staged in the following way:

• NX. Lymph nodes near the primary tumor cannot be evaluated.
• N0. Cancer has not spread to lymph nodes near the primary tumor.
• N1. Cancer has spread to lymph nodes near the primary tumor.

The last part of staging cervical cancer is to determine whether cancer has spread to other parts of the body (metastasized). The TNM system stages metastasis (M) in the following way:

• MX. Distant metastasis cannot be assessed.
• M0. No distant metastasis is found.
• M1. Metastasis to another part of the body has occurred.

The TNM staging system allows a health professional to recommend the most effective treatment options and discuss the long-term outcome (prognosis) based on the type of tumor, the stage of the cancer, and the woman's age and overall health condition.

FIGO staging¹

Stage I. Cervical carcinoma is only found in the cervix.

• Stage IA. Invasive carcinoma is diagnosed by microscopy, with the extent of the tumor into cell layers (stromal invasion) no more than 5mm in depth and 7mm wide.
  • Stage IA1. Stromal invasion is 3mm or less in depth and 7mm or less in width.
  • Stage IA2. Stromal invasion is between 3mm and 5mm in depth and 7mm or less in width.
• Stage IB. Visible tumor only on the cervix or by microscopy is larger than 5mm deep and 7mm wide.
  • Stage IB1. Visible tumor is 4cm or less in size.
  • Stage IB2. Visible tumor is greater than 4cm in size.

Stage II. Cancer extends beyond the cervix but not onto the pelvic wall. It involves the vagina but not as far as the lower third of the vagina.

• Stage IIA. Tumor does not involve the connective tissue (parametrium) around the uterus, but does involve the upper two-thirds of the vagina.
• Stage IIB. Tumor does involve the parametrium but not the pelvic sidewall.

Stage III. Cancer has extended onto the pelvic sidewall and involves the lower third of the vagina. Stage III includes tumors that block urine so it cannot flow out of the kidney or that cause a nonfunctioning kidney.

• Stage IIIA. Tumor involves lower third of vagina but no extension into the pelvic wall.
• Stage IIIB. Tumor extends onto the pelvic sidewall or causes a blocked kidney or nonfunctioning kidney.

Stage IV. Tumor invades the lining of the bladder or rectum, or extends beyond the pelvis.

• Stage IVA. Tumor has spread into other pelvic structures such as the bladder or rectum.
• Stage IVB. Cancer has spread to distant organs.

Citations

1. National Cancer Institute (2005). Cervical Cancer (PDQ): Treatment-Health Professional Version. Available online: http://www.cancer.gov/cancertopics/pdq/treatment/cervical/healthprofessional.