Grading uterine cancer

Last medical review:

Grading describes how the cancer cells look compared to normal, healthy cells. Knowing the grade gives your healthcare team an idea of how quickly the cancer may be growing and how likely it is to spread. The grade can also help the healthcare team predict future outcomes (prognosis) and how the cancer might respond to treatment. The grade is also used to stage uterine cancer.

To find out the grade of uterine cancer, a pathologist looks at a tissue sample from the uterus under a microscope. They look at how different the cells look from normal cells (called differentiation) and other features of the tumour such as the size and shape of the cells and how the cells are arranged. They can usually tell how fast a tumour is growing by looking at how many cells are dividing.

Usually, the pathologist gives uterine cancer a grade of 1 to 3. A lower number means the cancer is low grade.

Low-grade cancers have cancer cells that are well differentiated. The cells are abnormal but look a lot like normal cells and are arranged a lot like normal cells. Low-grade cancers tend to grow slowly and are less likely to spread.

High-grade cancers have cancer cells that are poorly differentiated or undifferentiated. The cells don't look like normal cells and are arranged very differently. High-grade cancers tend to grow more quickly and are more likely to spread than low-grade cancers.

Grading system for endometrial carcinoma

The International Federation of Gynecology and Obstetrics (FIGO) developed a grading system for endometrial carcinoma. It's based on the percentage of cells in the tumour that grow in sheets (called solid tumour growth) rather than form glands. It may also take into account the level of differentiation as well.

FIGO grade

Description

1

5% or less of tumour tissue is solid tumour growth. The cancer cells are well differentiated.

2

Between 6% and 50% of tissue is solid tumour growth. The cancer cells are moderately differentiated.

3

More than 50% of tissue is solid tumour growth. The cancer cells are poorly differentiated.

Sometimes, healthcare teams will use a simpler system from the World Health Organization (WHO) that only has 2 grades: low grade and high grade. In this system, low-grade endometrial carcinoma is made up of FIGO grades 1 and 2, and high-grade endometrial carcinoma is made up of FIGO grade 3.

If you were diagnosed with a type of uterine cancer other than endometrial carcinoma, talk to your doctor about grading of the cancer.

Expert review and references

  • Hacker NF, Friedlander ML. Uterine cancer. Berek J, Hacker NF. Berek and Hacker's Gynecologic Oncology. 7th ed. Philadelphia, PA: Wolters Kluwer; 2021: 10:371–420.
  • Koskas M, Amant F, Mirza MR, Creutzberg CL. Cancer of the corpus uteri: 2021 update. International Journal of Gynecology and Obstetrics. 2021: 155(Suppl 1):45–60.
  • PDQ Adult Treatment Editorial Board. Uterine Sarcoma Treatment (PDQ®)–Health Professional Version. National Cancer Institute; 2022. https://www.cancer.gov/.
  • Powell MA, Olawaiye AB, Bermudez A, et al. Corpus uteri – carcinoma and carcinosarcoma. Amin, MB (ed.). AJCC Cancer Staging Manual. 8th ed. American College of Surgeons; 2017: 53:688–697.
  • Soslow RA, Tornos C, Park KJ, et al. Endometrial carcinoma diagnosis: use of FIGO grading and genomic subcategories in clinical practice: recommendations of the International Society of Gynecological Pathologists. International Journal of Gynecological Pathology. 2019: 38 Suppl 1(Iss 1 Suppl 1):S64–S74.

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