The peritoneum is specifically located in the abdominal area, not elsewhere in the body.

Location Specific

The peritoneum has two layers, one that lines the abdominal wall and one that encloses the organs.

Two Layers

Peritoneum is mainly used in medical or anatomical contexts, not in everyday conversation.

Medical Context

 As the cells proliferate, they spread via one of the three common routes of transcoelomic, lymphatic, or hematogenous spread. In transcoelomic spread, malignant cells penetrate the covering surfaces of cavities in our body. These surfaces are known as peritoneum

How does cancer spread...

 support so the muscles won't tear in any one direction you've got that cross support so you're now into peritoneum now yep