Stages and grades

When you're diagnosed, your medical team will aim to identify how much cancer there is, how far it's spread, and how fast it's likely to grow and spread.

Understanding if and how the cancer has spread (the stage) and how different your cancer cells look to normal cells (the grade) can help you when discussing your diagnosis, treatment and prognosis with your specialist. But you may not wish to know so much detail – it's a personal choice.

Stages

An international system of staging is used to look at how far the cancer has spread. This involves scans, examining you during surgery and taking some samples of tissue (biopsies). Finding out the stage of the cancer is an important part of diagnosis because it can affect your treatment options. This staging system is called the FIGO system, named after its authors, the International Federation of Gynaecological Oncologists (Fédération Internationale de Gynécologie et d'Obstétrique).

Another staging system used is called TNM. It takes into account the size of the tumour (T), whether the cancer has spread to the lymph glands/lymph nodes (N), and whether the tumour has spread anywhere else in the body (M – for metastases). The TNM staging is less commonly used in gynaecological cancers. 

Metastases are lumps of cancer cells away from the primary cancer. Cells from the primary cancer can spread to other organs through the blood vessels and lymph vessels. 

These staging codes are also used in staging fallopian tube and primary peritoneal cancer, which are treated in a similar way to ovarian cancer.

Stage 1

The cancer is limited to the ovary/ovaries or fallopian tubes (that connect the ovaries to the womb, where a baby is carried during pregnancy) and hasn’t spread further.

  • Stage 1A
    Only one ovary (or fallopian tube) is affected by the cancer, and the tumour is only inside the affected ovary or fallopian tube. No cancer is found on the surface of the ovary or fallopian tube. No cancerous cells are found in the washing fluid (fluid used to check for cancer cells) from the abdomen (tummy) and pelvis (the lower part of the tummy between your hip bones). 
  • Stage 1B
    Both ovaries (or fallopian tubes) are affected by the cancer. But no cancer is found on either the surface of the ovaries (or fallopian tubes) or in washing fluid taken from the tummy and pelvis.
  • Stage 1C
    The cancer is limited to one or both ovaries or fallopian tubes, with any of the following: 
    • Stage 1C1
      The ovary tissue around the tumour (the capsule) is broken as it was burst during the surgery.
    • Stage 1C2
      The ovary capsule burst before surgery or there’s evidence of cancer on the surface of at least one of the ovaries or fallopian tubes.
    • Stage 1C3
      Cancerous cells are detected in washing fluid taken from the tummy or pelvis. 
Stage 2

The cancer is in one or both ovaries or fallopian tubes and has spread into the pelvis. There’s no spread of the tumour outside of the pelvis.  

  • Stage 2A
    The cancer has spread into the womb and/or fallopian tubes. 
  • Stage 2B
    The cancer has spread to other organs in the pelvis, for example the bladder or rectum (the last part of the large intestine before the anus, where waste leaves the body). 
Stage 3

The cancer has spread outside of the pelvis into the tummy area and/or the lymph nodes at the back of the tummy (retroperitoneal lymph nodes). Lymph nodes are small lumps of tissue that help our bodies to fight infection.

  • Stage 3A
    The cancer is in one or both ovaries or fallopian tubes, and has spread to the lymph nodes, with or without spread outside the pelvis. During surgery no cancer can be seen outside the pelvis to the naked eye. But tiny deposits of cancer are found in the lining of the tummy (peritoneum) or in the sheet of fatty tissue in front of the tummy (omentum) under a microscope.
    • Stage 3A1   
      The cancer is in one or both ovaries or fallopian tubes, and it has spread to the lymph nodes at the back of the tummy (retroperitoneal lymph nodes) only. It hasn’t spread to organs further away.   
      • Stage 3A1(i) is when the tumour in the lymph nodes measures 10 mm or less 
      • Stage 3A1(ii) is when the tumour in the lymph nodes measures more than 10 mm
    • Stage 3A2
      The cancer is in one or both ovaries or fallopian tubes, and it has spread to the lining of the tummy (peritoneum) outside the pelvis.  This may not have been visible to the naked eye at the time of surgery, but has been seen when it’s examined in the lab. The cancer might or might not have spread to lymph nodes at the back of the tummy (retroperitoneal lymph nodes). 
  • Stage 3B
    Tumours smaller than 2cm in diameter can be seen outside the pelvis within the tummy. Nearby lymph nodes may or may not contain cancerous cells.
  • Stage 3C
    Tumours bigger than 2cm are found outside the pelvis within the tummy. They may be on the outside of the liver (in the upper right side of the tummy) or spleen (in the upper left side of the tummy). 
Stage 4

The cancer has spread outside of the tummy and pelvis to organs further away. 

  • Stage 4A
    The cancer cells are found in the fluid around the lungs.
  • Stage 4B
    The cancer has spread to the inside of the spleen or liver or to lymph nodes further away or to other organs such as the lungs and bones. 

Grades

Grading refers to how similar cancer cells look to normal cells and can help predict how the cancer will behave. This includes how fast it's likely to grow and spread, which may impact on the treatments recommended for you

There are some ovarian tumours that rarely spread. These are called borderline or atypically proliferative tumours (not cancers). 

In the most common type of ovarian cancer the tumours are simply divided into low-grade and high-grade and a grading number isn’t given. The most common type of ovarian cancer is high-grade serous carcinoma. There is also low-grade serous, which is less common. High grade tumours are also more likely to respond to chemotherapy compared to low grade tumours. 

All other ovarian cancers are graded as 1, 2 and 3.  

  • Grade 1 (well differentiated) cancers have cells that closely look like normal cells and are less likely to spread or recur (come back).

  • Grade 2 (moderately differentiated) cancers and grade 3 (poorly differentiated) cancers show increasing difference of appearance compared to normal cells. They are also more likely to spread and recur (come back). 

Differentiation is the process by which cells change in structure and become specialised for their role and place in the body. Well differentiated tumours are highly specialised for their role and place. The cells and tissue structures are very similar to normal tissues. 


Last reviewed: April 2022

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