Colorectal Cancer

You are more than just your cancer. We want you to thrive. 

If you’ve been diagnosed with colorectal cancer, Siteman Cancer Center is here to help. WashU Medicine physicians at Siteman create a plan that’s customized to treat your cancer — based on your age, your lifestyle, and your goals. 

Siteman’s advanced approach to colorectal cancer care draws on the expertise of a multidisciplinary team of surgeons, medical oncologists, and radiation oncologists. Together they work to deliver the most effective, personalized treatment possible. 

Your team of WashU Medicine physicians, from surgeons to radiation oncologists, take a precise approach to your care, maximizing the full effectiveness of treatments while protecting overall wellbeing. This requires the skill and experience Siteman subspecialists have gained by seeing hundreds of patients with colorectal cancer each year.   

Because Siteman is a leader in colorectal cancer, our patients receive minimally invasive surgeries and short courses of radiation therapy, called hypofractionation, to promote fewer treatments, limit side effects, ensure faster recoveries, and increase survivability.  

What are my treatment options for colorectal cancer? 

Colorectal cancer treatment depends on several factors, including the location of the cancer (colon, rectum, or anus), the stage of your cancer, and your overall health. Many patients receive a combination of treatments. Your WashU Medicine team at Siteman Cancer Center will explain every option and what to expect for a personalized care plan. 

The main treatment options for colorectal cancer include: 

• Surgery 
• Radiation therapy 
• Chemotherapy 
• Chemoradiation / Total Neoadjuvant Therapy (TNT) 
• Targeted therapy 
• Immunotherapy 
• HIPEC (Heated Intraperitoneal Chemotherapy) 
• Clinical trials 

What surgeries does Siteman offer for colorectal cancer? 

Surgery is the most common first-line treatment for colorectal cancer. For patients with early-stage tumors, surgery alone may achieve cure. For more advanced cases, surgery is often combined with chemotherapy, radiation, or both. 

WashU Medicine colorectal surgeons at Siteman are internationally recognized experts — treating approximately 350 new cancer patients each year. They use minimally invasive and robotic techniques whenever possible to reduce complications, limit blood loss, shorten hospital stays, and speed recovery. 

Types of surgery for colon and rectal cancers 

The type of surgery recommended depends on the size, location, and stage of your tumor. Your surgical team at Siteman will walk you through every option before making a recommendation. 

Because the rectum is positioned deep in the pelvis, surgical treatment for rectal cancer is technically complex. Siteman’s surgeons have pioneered sphincter-sparing techniques that allow most patients to avoid a permanent colostomy and maintain normal bowel function. 

Colonoscopic resection: For very small tumors confined to a polyp, a surgeon may remove the cancer entirely during a colonoscopy — no incision required. 

Partial colectomy (laparoscopic or robotic): The most common colon surgery. A section of the colon containing the tumor — along with a margin of healthy tissue and nearby lymph nodes — is removed. More than 60% of partial colectomies at Siteman are performed using minimally invasive techniques, including robotic-assisted surgery. 

Metastasectomy: When colorectal cancer has spread to another organ — most commonly the liver, lungs, or pelvis — surgeons at Siteman are skilled at removing those metastatic tumors using specialized techniques. 

Sphincter-sparing resection: When the tumor does not involve the anal sphincter muscle or pelvic floor, WashU Medicine surgeons at Siteman can remove the tumor while leaving those structures intact, preserving bowel function. 

Transanal endoscopic microsurgery (TEM): A minimally invasive procedure used to remove early-stage tumors located high inside the rectum, without abdominal incisions. 

Ostomy: In some cases, a temporary or permanent opening (stoma) is created to allow waste drainage after colorectal surgery as your body heals. A dedicated ostomy nurse will train patients on care and management. For most patients, ostomies are a temporary measure. 

When do patients with colorectal cancer receive radiation therapy? 

Radiation therapy uses high-energy beams to target and destroy cancer cells. It is used more commonly for rectal cancer than colon cancer, often in combination with chemotherapy. 

Your WashU Medicine radiation oncologist will make a personalized recommendation based on the location of your tumor, its stage, and your overall health. Radiation may be recommended: 

• Before surgery to shrink a tumor and improve surgical outcomes 
• After surgery to destroy any remaining cancer cells 
• Alongside chemotherapy (chemoradiation) to treat locally advanced rectal cancer 
• As palliative therapy to relieve symptoms such as pain or bleeding in advanced disease 

WashU Medicine radiation oncologists at Siteman are national leaders in using shorter durations of radiation, called hypofractionation, to achieve the same strong results — meaning patients often complete their treatment more quickly than at other cancer centers. 

Total Neoadjuvant Therapy (TNT) for Rectal Cancer 

TNT is an approach used for locally advanced rectal cancer in which both chemotherapy and radiation therapy are delivered before surgery. This combination shrinks tumors, improves the chances of sphincter preservation, and may allow some patients to avoid surgery altogether. 

WashU Medicine radiation oncologists at Siteman have shortened the standard TNT for patients so they can complete treatment sooner, effectively.  

Types of radiation therapy 

External beam radiation therapy (EBRT): The standard approach for rectal cancer. A linear accelerator delivers targeted radiation beams from outside the body to the tumor site. 

Intensity Modulated Radiation Therapy (IMRT): An advanced technique that maps radiation doses to the 3D shape of the tumor, protecting surrounding healthy tissue — particularly important near pelvic structures. 

MR-guided adaptive radiation therapy: This therapy uses MRI images to deliver radiation for highly-targeted treatment to see how radiation is impacting the tumor during the treatment, enabling them to make adjustments in real time.  

Siteman Cancer Center was the first institution in the world to use MR-guided adaptive radiation therapy to treat a patient. The technology was developed by WashU Medicine physicians and researchers at Siteman. 

Stereotactic Body Radiation Therapy (SBRT): Delivers high, focused doses over a small number of sessions. May be used for metastatic colorectal cancer sites (e.g., liver or lung lesions).

What is HIPEC, and when is it used for colorectal cancer?

HIPEC (Heated Intraperitoneal Chemotherapy) is a specialized surgical procedure used when colorectal cancer has spread to the lining of the abdominal cavity — a condition called peritoneal metastasis. 

For HIPEC, first WashU Medicine surgeons remove visible tumors (called cytoreduction), then they use heated chemotherapy to ensure all remaining cancer cells are killed. The chemotherapy circulates in the abdomen for 60-90 minutes.  

Siteman is one of the few cancer centers in the U.S. to offer cytoreduction and HIPEC for colorectal and other cancers.  

What is drug therapy for colorectal cancer? 

Drug therapy, also called systemic therapy, is a broad term for any colorectal cancer treatment delivered through medication. These medicines can be given as a pill or through an IV infusion. Systemic therapies are designed to treat cancer throughout the body so they can reach wherever cells may have spread. 

Depending on your diagnosis, your physician may use drug therapy to shrink a tumor before surgery, destroy cancer cells after surgery, slow the growth of advanced cancer, or improve your quality of life during treatment. 

Types of drug therapy 

At Siteman Cancer Center, drug therapy for colorectal cancer includes chemotherapy, targeted therapy, and immunotherapy. 

Chemotherapy uses drugs that kill cancer cells throughout the body. Patients typically receive chemotherapy through an IV in multi-week cycles.

Targeted therapy attacks specific molecular features of cancer cells that allow them to grow and spread. Unlike chemotherapy, which affects all rapidly dividing cells, targeted drugs pinpoint exactly where cancer cells are vunerable. 

Immunotherapy harnesses your immune system to recognize and attack cancer cells. The most common immunotherapies for colorectal cancer are checkpoint inhibitors. These are most often used in patients with advanced disease or those with specific genetic mutations. WashU Medicine physicians at Siteman are studying immunotherapy in clinical trials to expand its use to a broader group of patients.