So with regards to staging, we use a what’s called TNM model. So that’s tumor, nodes and metastatic disease. With the T stage, we’re looking at tumor depth and we use T one through four. The most important point is whether the tumor has invaded through the muscular layer of the colon or rectum. And that really turns it into a T3 lesion. And once a patient has a T3 lesion, especially in the rectum, we would want to do upfront chemotherapy and / or radiation to really help downstage those patients. In patients that have a T1 lesion that is still not through the submucosa, those are the lesions in the rectum that we can potentially resect upfront and then follow. T4 lesions have invaded through the colon or rectum and are potentially invading other organs or even the sphincter complex. In those situations, especially in the rectum, we would also want upfront chemotherapy and radiation.
Nodal status is also important, and oftentimes we can’t determine that until after surgery. Sometimes with a pelvic MRI, we can assume that nodes are positive and we may upfront treat even if we assume they’re positive. However, after surgery, if they are positive on our specimen, you would need to see a medical oncologist if you haven’t already, for potentially post-surgical chemotherapy. Now, the M staging is metastatic disease. With regards to colon and rectal cancer, we’re normally looking in the liver or the lung as sites of metastatic disease. That’s why we obtain the CT scans of the chest and the abdomen. If you did have metastatic disease to the lungs or the liver, you would need to see a medical oncologist, as long as you are asymptomatic from your primary tumor for potential chemotherapy.