Types of womb (endometrial) cancer
The majority of people who have investigations will be found not to have womb cancer.
There are several different types of womb cancer, the most common of which (95%) is called adenocarcinoma and starts in the lining of the womb. Adenocarcinomas can be sub-classified as endometrioid, uterine serous or clear cell carcinomas. These different types refer to the type of cells that form the cancer. Other rarer types of womb cancer include uterine carcinosarcoma and uterine sarcoma and which starts in the muscle layer of the womb.
Grade of womb cancer
The grade of the cancer is how abnormal the cells look under a microscope. This gives the medical team an idea of how quickly the cancer might grow or whether it is likely to spread. Womb cancer can be classified as Grade 1, 2 or 3. Grade 1 cancers tend to be slower growing and are less likely to spread. Grade 3 cancers tend to be faster growing and are more likely to spread.
Staging
The stage of a cancer is a measure of how big the tumour is and whether it has spread.
- Stage 1 (either 1A or 1B) means that the cancer is within the womb and has not spread outside of the womb.
- Stage 2 means that the cancer has grown into the cervix (the neck of the womb).
- Stage 3 means that the cancer has spread outside of the womb but is still within the pelvis. These can be stage 3A, 3B or 3C.
- Stage 4 (A or B) means that the cancer has spread outside of the pelvis to other areas of the body.
Pre-cancerous diagnoses
Investigations may diagnose a pre-cancerous change within the lining of the womb, known as endometrial hyperplasia. Hyperplasia can be diagnosed with or without atypia (how normal the cells look under the microscope). Hyperplasia is an irregular thickening of the womb lining and if left untreated, can progress to womb cancer.
You may find it useful to watch Peaches support video:
Understanding womb cancer.
Molecular testing in womb cancer
You may notice when you receive your test results from either your womb biopsy or after surgery, that molecular testing has been performed. Molecular testing looks at three key features called POLE, MMR, and p53. These are all involved in how cells copy and protect their DNA (genetic material). Changes in these systems can affect how a cancer grows and how it responds to treatment.
These molecular tests are performed on either your initial biopsy or sometimes after surgery on the tissue from hysterectomy. They help your treatment team understand:
- How your cancer may behave and help predict whether the cancer is more or less likely to come back.
- If you may need more treatment after surgery (chemotherapy and/or radiotherapy).
- Whether certain treatments, such as immunotherapy, may be effective.
- If you have an inherited condition that increases cancer risk (i.e. Lynch Syndrome).
What is POLE?
POLE is a gene that helps cells copy their DNA accurately when they divide. It acts like a proofreader, checking for mistakes and fixing them.
- In some womb cancers, the POLE gene does not work properly, leading to many small DNA changes in the cancer cells (POLE-mutant).
- Although this sounds worrying, POLE-altered cancers often behave less aggressively and respond well to treatment.
- People with POLE-mutant cancers usually have an excellent outlook.
What is MMR?
MMR stands for Mismatch Repair. It is a system of proteins that repair DNA mistakes that happen naturally when cells divide.
- If the MMR system is not working (MMR-deficient), errors build up in the DNA, causing cancer to develop.
- Some MMR-deficient cancers respond particularly well to immunotherapy.
- MMR problems can sometimes be linked to an inherited condition called Lynch syndrome, so further testing may help identify people and families who could benefit from genetic counselling.
What is p53?
p53 is a protein that helps to stop damaged cells from growing and tells them when to repair themselves or when to die.
- If p53 is not working properly (p53-abnormal), damaged cells can continue to grow uncontrollably.
- Cancers with abnormal p53 tend to behave more aggressively and may need more intensive treatment and closer follow-up.
- A normal functioning p53 gene is termed p53-wild type.
The combination of these results is used with the cancer stage and grade to guide the treatment decisions. Overall, the introduction of molecular testing allows care to be more personalised, helping ensure patients receive treatment that is better matched to their specific cancer, while avoiding unnecessary treatment when possible.
You may find it useful to watch Peaches support video:
Molecular classification of womb cancer.
