Understanding lower gastrointestinal cancer

Lower gastrointestinal cancer (also called bowel or colorectal cancer) happens in the large intestine of the digestive system. The digestive system (how we eat and process food) has two intestines that travel from the stomach to the anus. The large intestine is about 1.5 metres long and is the lowest part of the digestive system. The two intestines are:

  • Small intestine (or small bowel) – where food comes from the stomach and is further broken down into vitamins and nutrients we need to live
  • Large intestine (or large bowel) – is connected to the small intestine. This is where the food product passes to, from the small intestine. This food product moves into the colon, where water is absorbed from it and the leftover remains (or waste) then pass into the rectum (the last few inches of the colon) and leaves the body via the anus (bowel motion).

Focusing on you

Placing you at the centre of our work, your specialist will determine where you cancer started and how far it has progressed.

Lower gastrointestinal cancers can happen in any area of the large intestine but most usually start in the lining or tissue (inside wall) of the large intestine. Most colon cancers start when small clump of cells come together to form into a polyp (a small lump on a stalk/stem/tail growing from the tissue). Over time these polyps can become abnormal and grow into cancer. It can spread through the muscle, tissue and wall of the bowel and into other nearby organs.

If you have noticed a change in your bowel motions (going to the toilet) and are worried, please visit your GP (General Practitioner or local family doctor) as soon as possible.

Enhancing your care

At Peter Mac, we provide the most up-to-date diagnostics (tests) and treatment for colon cancers.

Our lower gastrointestinal cancer specialists will come together and work with you to assess your condition and plan and deliver the most effective treatment.

Your care plan will be custom-made to treat your specific colon cancer and the needs most important to you.


We know how hard cancer and treatment can be. Your lifestyle and that of your loved one's will be disrupted and changed. During this time, it is common to struggle with ongoing concerns about cancer and therapy. There are many expert groups available to support you through this time, including:


At Peter Mac, we focus on all aspects of your health and wellbeing. Our lower gastrointestinal experts will help support and guide you to the best information and managed care.

Our specialist nurses can refer you to our:


For more information about lower gastrointestinal cancers, their treatment and support for patients and families, download copies of the following resources: 


Your needs come first, so we offer expert care across a number of different Lower Gastrointestinal diseases including:

Colon cancer
Rectal cancer
Metastatic colorectal cancer
Anal cancer
Advanced pelvic cancer
Appendix cancer
Peritoneal cancer
Pseudomyxoma peritonei