TNM Definitions
AJCC Stage Groupings
FIGO Staging

Cervical carcinoma has its origins at the squamous-columnar junction whether in the endocervical canal or on the portio of the cervix. The precursor lesion is dysplasia or carcinoma in situ (cervical intraepithelial neoplasia [CIN]), which can subsequently become invasive cancer. This process can be quite slow. Longitudinal studies have shown that in untreated patients with in situ cervical cancer, 30% to 70% will develop invasive carcinoma over a period of 10 to 12 years. However, in about 10% of patients, lesions can progress from in situ to invasive in a period of less than 1 year. As it becomes invasive, the tumor breaks through the basement membrane and invades the cervical stroma. Extension of the tumor in the cervix may ultimately manifest as ulceration, exophytic tumor, or extensive infiltration of underlying tissue including bladder or rectum.

In addition to local invasion, carcinoma of the cervix can spread via the regional lymphatics or bloodstream. Tumor dissemination is generally a function of the extent and invasiveness of the local lesion. While cancer of the cervix generally progresses in an orderly manner, occasionally a small tumor with distant metastasis is seen. For this reason, patients must be carefully evaluated for metastatic disease.

Stages are defined by the Federation Internationale de Gynecologie et d’Obstetrique (FIGO) or the American Joint Committee on Cancer’s (AJCC) TNM classification.[1-3]

The definitions of the T categories correspond to the several stages accepted by FIGO.

TNM Categories/FIGO Stages

Primary tumor (T)

• TX: Primary tumor cannot be assessed
• T0: No evidence of primary tumor
• Tis/0: Carcinoma in situ
• T1/I: Cervical carcinoma confined to uterus (extension to corpus should be disregarded)
  • T1a/IA: Invasive carcinoma diagnosed only by microscopy. All macroscopically visible lesions—even with superficial invasion—are T1b/IB. Stromal invasion with a maximum depth of 5 mm measured from the base of the epithelium and a horizontal spread of 7 mm or less. Vascular space involvement, venous or lymphatic, does not affect classification
  • T1a1/Ia1: Measured stromal invasion 3 mm or less in depth and 7 mm or less in horizontal spread
  • T1a2/IA2: Measured stromal invasion 3 mm or more and 5 mm or less with a horizontal spread of 7 mm or less
  • T1b/IB: Clinically visible lesion confined to the cervix or microscopic lesion larger than T1a/IA2
  • T1b1/IB1: Clinically visible lesion 4 cm or smaller in greatest dimension
  • T1b2/IB2: Clinically visible lesion 4 cm or larger in dimension
• T2/II: Cervical carcinoma invades beyond the uterus but not to the pelvic wall or to the lower third of the vagina
  • T2a/IIA: Tumor without parametrial involvement
  • T2b/IIB: Tumor with parametrial involvement
• T3/III: Tumor extends to the pelvic wall, and/or involves the lower third of the vagina, and/or causes hydronephrosis or nonfunctioning kidney
  • T3a/IIIA: Tumor involves the lower third of the vagina and does not extend to the pelvic wall
  • T3b/IIIB: Tumor extends to the pelvic wall and/or causes hydronephrosis or nonfunctioning kidney
• T4/IVA: Tumor invades mucosa of the bladder or rectum and/or extends beyond the true pelvis (bullous edema is not sufficient to classify a tumor as T4)

Regional lymph nodes (N)

• NX: Regional lymph nodes cannot be assessed
• N0: No regional lymph node metastasis
• N1: Regional lymph node metastasis

Distant metastasis (M)

• MX: Distant metastasis cannot be assessed
• M0: No distant metastasis
• M1/IVB: Distant metastasis

Stage 0

• Tis, N0, M0

Stage 0 is carcinoma in situ or intraepithelial carcinoma. There is no stromal invasion.

Stage I

• T1, N0, M0

Stage IA

• T1a, N0, M0

Stage IA1

• T1a1, N0, M0

Stage IA2

• T1a2, N0, M0

Stage IB

• T1b, N0, M0

Stage IB1

• T1b1, N0, M0

Stage IB2

• T1b2, N0, M0

Stage II

• T2, N0, M0

Stage IIA

• T2a, N0, M0

Stage IIB

T2b, N0, M0

Stage III

• T3, N0, M0

Stage IIIA

• T3a, N0, M0

Stage IIIB

• T1, N1, M0
• T2, N1, M0
• T3a, N1, M0
• T3b, any N, M0

Stage IVA

• T4, any N, M0

Stage IVB

• Any T, any N, M1

Stage I

Stage I is carcinoma strictly confined to the cervix; extension to the uterine corpus should be disregarded.

• Stage IA: Invasive cancer identified only microscopically. All gross lesions even with superficial invasion are stage IB cancers. Invasion is limited to measured stromal invasion with a maximum depth of 5 mm* and no wider than 7 mm. [Note: *The depth of invasion should be 5 mm or less taken from the base of the epithelium, either surface or glandular, from which it originates. Vascular space involvement, either venous or lymphatic, should not alter the staging.]
  • Stage IA1: Measured invasion of the stroma 3 mm or less in depth and 7 mm or less in diameter.
  • Stage IA2: Measured invasion of stroma more than 3 mm but 5 mm or less in depth and 7 mm or less in diameter.
• Stage IB: Clinical lesions confined to the cervix or preclinical lesions greater than stage IA.
  • Stage IB1: Clinical lesions 4 cm or less in size.
  • Stage IB2: Clinical lesions 4 cm or more in size.

Stage II

Stage II is carcinoma that extends beyond the cervix but has not extended onto the pelvic wall. The carcinoma involves the vagina but not as far as the lower third section.

• Stage IIA: No obvious parametrial involvement. Involvement of as much as the upper two thirds of the vagina.
• Stage IIB: Obvious parametrial involvement but not onto the pelvic sidewall.

Stage III

Stage III is carcinoma that has extended onto the pelvic sidewall and/or involves the lower third of the vagina. On rectal examination, there is no cancer-free space between the tumor and the pelvic sidewall. All cases with a hydronephrosis or nonfunctioning kidney should be included, unless they are known to be due to other causes.

• Stage IIIA: No extension onto the pelvic sidewall but involvement of the lower third of the vagina.
• Stage IIIB: Extension onto the pelvic sidewall or hydronephrosis or nonfunctioning kidney.

Stage IV

Stage IV is carcinoma that has extended beyond the true pelvis or has clinically involved the mucosa of the bladder and/or rectum.

• Stage IVA: Spread of the tumor onto adjacent pelvic organs.
• Stage IVB: Spread to distant organs.

References

1. Shepherd JH: Cervical and vulva cancer: changes in FIGO definitions of staging. Br J Obstet Gynaecol 103 (5): 405-6, 1996.  [PUBMED Abstract]
   
   
2. Creasman WT: New gynecologic cancer staging. Gynecol Oncol 58 (2): 157-8, 1995.  [PUBMED Abstract]
   
   
3. Cervix uteri. In: American Joint Committee on Cancer.: AJCC Cancer Staging Manual. 6th ed. New York, NY: Springer, 2002, pp 259-65. 
   
   

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