Carrie Peterson, MD, MS, explains how physicians with the Froedtert & the Medical College of Wisconsin Colorectal Cancer Program successfully treat people with colorectal cancer using innovative surgeries, drugs and radiation therapy techniques.

Carrie Peterson, MD, MS

Q: What should people know about colorectal cancer?

Dr. Peterson: Get screened. With a colonoscopy, we can remove growths before they turn into cancer and biopsy suspicious growths for testing in one procedure. Stool tests are also effective in screening for cancer in many people.  

Q: Are younger people getting colorectal cancer?

Dr. Peterson: Yes, and accordingly, the age for a first screening has gone from 50 to 45. We think the younger onset age is an environmental factor, not a hereditary factor.

Q: Why is it important for people with colorectal cancer to see a colorectal cancer specialist?

Dr. Peterson: Treatments, especially for rectal cancer, have changed dramatically in the last three years. Our team sees a large number of patients and conducts clinical trials. We know the treatment nuances — especially for people with complicated medical histories and familial syndromes that increase the risk of developing colorectal cancers. Doctors who study and treat colorectal disease every day are more aware of the latest treatments. Our multidisciplinary approach means we meet every week — surgeons, radiation and medical oncologists and other specialists — to review a patient’s diagnosis and treatment plan. This focused expertise influences outcomes.

Q: Describe the latest advances in colorectal surgery.

Dr. Peterson: Minimally invasive procedures like laparoscopic and robotic surgery offer less blood loss, faster recovery and effectiveness equal to traditional surgery. Robotic surgery may help preserve pelvic nerves and sexual function. We also offer sphincter-preserving surgery for eligible patients. People worry about ending up with an ostomy — an opening in the belly to expel waste through a tube into a pouch. A patient may need an ostomy if anal muscle is involved with the tumor and muscle must be removed to get all the tumor out. In some situations, an ostomy may be temporary.

Q: Does everyone need surgery?

Dr. Peterson: No. In 30% to 60% of patients with rectal cancer, the tumor could go away with initial treatment, and we may take a watch-and-wait approach instead of surgery. Because there is a chance the tumor will return, we monitor carefully with scope procedures and imaging so treatment can start promptly, if needed. With colon cancer, due to a lower risk of recurrence, surgery is the first step and sometimes the only treatment needed.

Q: How about immune therapies?

Dr. Peterson: Immunotherapy is a promising treatment for some people, but you must have a certain gene mutation to be eligible. We test everyone diagnosed with colorectal cancer for mutations.

Q: Are there more targeted ways of addressing radiation therapy?

Dr. Peterson: We are one of only a few centers to offer the Unity MR-linac, which combines MRI with a linear accelerator. It's highly precise, allowing us to adjust the radiation dose to the tumor's exact position and size during each session.

Q: What about clinical trials?

Dr. Peterson: When tumor cells die, they release bits of DNA into the bloodstream. We have several trials, including one exploring a blood test for circulating tumor DNA to tell us if a tumor is gone after treatment.

Q: Are there options for late-stage, inoperable or metastatic disease?

Dr. Peterson: Even if the tumor has spread to the liver or the lungs, we can sometimes remove it with surgery. If we can’t, treatments like chemotherapy or targeted drug therapy are options. 

Colon Cancer Screening Can Save Your Life

Screening not only finds colon cancer early, but a colonoscopy may also prevent it from developing by removing precancerous growths called polyps. Learn more about colon cancer screenings