Stages of peritoneal cancer

 When it’s first diagnosed, peritoneal cancer is staged according to its size, position, and where it’s spread from. It’s also given a grade, which estimates how quickly it’s able to spread.

Primary peritoneal cancer

Primary peritoneal cancer is staged with the same system used for ovarian cancer since the cancers are similar. But primary peritoneal cancer is always classed as stage 3 or stage 4. Ovarian cancer has two earlier stages.

Stage 3 is divided into three further stages:

• 3A. The cancer has spread to lymph nodes outside the peritoneum, or cancer cells have spread to the surface of the peritoneum, outside the pelvis.
• 3B. The cancer has spread to the peritoneum outside the pelvis. The cancer in the peritoneum is 2 centimeters (cm) or smaller. It may have also spread to lymph nodes outside the peritoneum.
• 3C. The cancer has spread to the peritoneum outside the pelvis and. The cancer in the peritoneum is larger than 2 cm. It may have spread to lymph nodes outside the peritoneum or to the surface of the liver or spleen.

In stage 4, cancer has spread to other organs. This stage is further divided:

• 4A. Cancer cells are found in the fluid that builds up around the lungs.
• 4B. The cancer has spread to organs and tissues outside the abdomen, such as the liver, lungs, or groin lymph nodes.

Secondary peritoneal cancer

Secondary peritoneal cancer is staged according to the primary cancer site. When a primary cancer spreads to another part of the body, such as the peritoneum, it’s usually classified as a stage 4 of the original cancer.