Stages of cervical cancer

The staging system for cervical cancer depends on the size of the tumour, the extent of the tumour 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 tumour (T) is staged in the following way:

• TX. Primary tumour cannot be assessed.
• T0. No primary tumour 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 5 mm in depth and 7 mm wide.
    • T1a1. Stromal invasion is 3 mm or less in depth and 7 mm or less in width. This is also called microinvasive carcinoma.
    • T1a2. Stromal invasion is between 3 mm and 5 mm in depth and 7 mm or less in width.
  • T1b. Visible tumour only on the cervix or microscopic tumour is larger than 5 mm in depth and 7 mm wide.
    • T1b1. Visible tumour is 4 cm (1.6 in.) or less in size.
    • T1b2. Visible tumour is more than 4 cm (1.6 in.) in size.
• T2. Cancer invades beyond the uterus but not to the pelvic wall or the lower third of the vagina.
  • T2a. Tumour does not involve the connective tissue (parametrium) around the uterus.
  • T2b. Tumour does extend into the parametrium around the uterus.
• T3. The tumour 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 non-functioning kidney.
  • T3a. Tumour involves lower third of vagina but no extension into the pelvic wall.
  • T3b. Tumour extends to pelvic wall and/or causes a blocked kidney or a non-functioning kidney.
• T4. Tumour 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 tumour (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 tumour cannot be evaluated.
• N0. Cancer has not spread to lymph nodes near the primary tumour.
• N1. Cancer has spread to lymph nodes near the primary tumour.

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 tumour, 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 tumour into cell layers (stromal invasion) no more than 5 mm in depth and 7 mm wide.
  • Stage IA1. Stromal invasion is 3 mm or less in depth and 7 mm or less in width.
  • Stage IA2. Stromal invasion is between 3 mm and 5 mm in depth and 7 mm or less in width.
• Stage IB. Visible tumour only on the cervix or by microscopy is larger than 5 mm deep and 7 mm wide.
  • Stage IB1. Visible tumour is 4 cm (1.6 in.) or less in size.
  • Stage IB2. Visible tumour is greater than 4 cm (1.6 in.) 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. Tumour does not involve the connective tissue (parametrium) around the uterus, but does involve the upper two-thirds of the vagina.
• Stage IIB. Tumour 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 tumours that block urine so it cannot flow out of the kidney or that cause a non-functioning kidney.

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

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

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

Author:	Shannon Erstad, MBA/MPH Carrie Henley	Last Updated: January 9, 2007
Medical Review:	Adam Husney, MD - Family Medicine Joy Melnikow, MD, MPH - Family Medicine Kevin Holcomb, MD - Gynecologic Oncology Deborah A. Penava, BA, MD, FRCSC, MPH - Obstetrics and Gynecology
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