From Colonoscopy To Colorectal Cancer Treatment Decisions

Waking up from a colonoscopy to hear that your doctor found a suspicious polyp or tumor can feel overwhelming. It is natural to have questions about what comes next, how a colorectal cancer diagnosis may be confirmed, and what your cancer treatment journey might look like.

While the wait for answers can be filled with anxiety, it is important to remember that colorectal cancer is often slow-growing, and taking the time to gather accurate information is a vital part of your care. From pathology reports and imaging to understanding cancer staging and treatment "villages," here is a guide on what to expect as you and your medical team move from a colonoscopy toward a personalized treatment plan.

Dipen Maun, MD, a colorectal surgeon at Franciscan Health Indianapolis and Mooresville, offers guidance on how colorectal cancer is diagnosed and how cancer treatment decisions are made.

Key Takeaways: Colon Cancer Diagnosis & Treatment

• A colonoscopy is the first step, not the final diagnosis. A colonoscopy identifies suspicious areas, but a colorectal cancer diagnosis is only confirmed after a pathologist analyzes a tissue biopsy. That typically takes three to seven days.
• Follow-up imaging provides the full picture. If colon cancer or rectal cancer is confirmed, tests like CT scans, PET scans and MRIs can be used to determine if the cancer is localized or has spread to other organs, such as the liver or lungs.
• Colorectal cancer staging guides your treatment. Colorectal cancer is staged from I to IV based on how deeply the tumor has grown into the colon wall and whether it has reached the lymph nodes or other parts of the body.
• Cancer treatment is a team effort. Care is "multidisciplinary," meaning a "village" of specialists—including surgeons, oncologists, and radiologists—works together to create a customized plan that may include surgery, chemotherapy, or radiation.

How Do Doctors Find Colon Polyps?

Colon polyps are typically found during a colonoscopy and often removed at that time.

“It's important to know that the colonoscopy doesn't actually confirm the cancer,” Dr. Maun said. “It just identifies a suspicious area, and that area must be tested. Usually, the doctor is able to take a biopsy during the colonoscopy and then send that specimen off to the lab.”

How Is Colorectal Cancer Initially Diagnosed?

Dr. Maun explained that pathologists will analyze the tissue under microscope to confirm whether cancer is found. This process can take up to seven days.

“At this point, the patient will get a phone call from the doctor explaining what was found,” Dr. Maun said. “We will likely recommend some additional testing, and typically a referral to a surgeon and/or a medical oncologist who can then outline the next steps in the treatment.

“While this is very anxiety-provoking for patients, I do want to stress that polyps and tumors are generally slow-growing. So, waiting a few days or a week to get the test done, to get the right appointment set, and imaging done is completely safe.”

What Imaging Tests Might Be Ordered To Confirm A Colorectal Cancer Diagnosis?

Typically a CT scan will be ordered to confirm a colon cancer diagnosis.

“That's a scan that really looks at the entire body from neck down to your pelvic area,” Dr. Maun said. “The goal is to see if any cancer cells have spread outside of the colon, with the most common locations of spread being the liver and the lung.”

For rectal cancer, an MRI or PET scan may be ordered in addition to the CT scan.

How Is Colorectal Cancer Staging Determined?

“Every tumor has its own staging protocol, and colon and rectal cancer has its own as well,” Dr. Maun said “There are typically four stages of colon or rectal cancer, and they're numbered between stages I to stage IV. Stage I is the earliest stage. It's the most curable, and it kind of goes up down to stage IV, which is unfortunately the hardest stage to get cures.”

The stages are often determined by the extent of the colorectal cancer’s spread.

“Oftentimes, to figure out stages I through three, this comes after surgery when the tumor is removed and the pathologist can look at the entire specimen in the lab,” Dr. Maun said.

Stage I colorectal cancer

“Stage I usually means the cancer is confined to the inner layers of the wall of the large intestine, and it hadn't spread through the wall,” Dr. Maun said.

Stage II colorectal cancer

“Stage II means it did erode through all the layers of the wall, but the tumor is still confined to the colon wall only,” he said.

Stage III colorectal cancer

“Stage III means that the tumor cells unfortunately have figured out how to get into the lymphatic system and have spread to the lymph nodes,” Dr. Maun said.

Stage IV colorectal cancer

Stage IV colorectal cancer can often be diagnosed during the CT scan or PET scan.

“In stage IV, the tumors now learned how to spread far away, usually through the blood or the lymphatics, and has attached to another organ like the liver or the lung,” he said.

What Are Colorectal Cancer Treatment Options?

“The treatment for colon and rectal cancer does take a village, and it's important to assemble the best possible team,” Dr. Maun said. “This is called a multidisciplinary approach, and it'll involve a handful of doctors. It might include a surgeon, a medical oncologist, a radiation oncologist, a radiologist, a pathologist amongst others. So, pretty important to have a very good team that's on your side.”

“Every case will be different, and every case will need a customized treatment plan.”

Colon cancer treatments

“Most colon cancer treatment plans that are not stage IV typically start with surgery. Surgery will entail removing the segment of large intestine that has the tumor in it and all of the surrounding lymph nodes that the tumor could possibly drain into. It's very commonly done in a minimally invasive fashion. That means making small incisions and using technology like laparoscopy or robotics.

“The surgeries typically take two to four hours, and most patients stay in the hospital between one and four days if the recovery is uneventful.”

Oncology care

“If the final pathology is stage III, many patients will then be recommended to see a medical oncologist, and be offered to do some chemotherapy for a few months after surgical recovery is complete,” Dr. Maun said. “Most chemotherapy regimens involve having a port access device placed in the chest so that the medicine can be diffused directly into large veins into the body. And what chemotherapy does is it circulates throughout the body. And it's able to kill cancer cells that are floating around or in another organ.”

Rectal cancer treatments

“When it comes to rectal cancer, even though it's the same tube, treatment is a little different,” Dr. Maun said. “It's very common for the regimen to treat rectal cancer to start with either or both chemotherapy and radiation therapy. As I mentioned, the chemo is infused into the bloodstream to help kill cancer cells. The radiation machine actually sends really high focused energy to a part of the body, such as the rectum, to kill cancer cells. And the chemo and the radiation work together to actually kill the cancer cells and make the tumor smaller.”

Following those treatments, surgical removal of part of the rectum that had the tumor may be part of the treatment plan.

“Rectal cancer surgeries are typically more challenging,” Dr. Maun said. “They take longer, and they can sometimes require an ostomy or a stool bag to divert the stool away from the surgical site. Most of the time, that bag is temporary. But sometimes that bag is permanent if the tumor is very close to the anus. Unfortunately, it's just necessary to ensure that all the cancer is removed and sometimes the entire organ does need to be taken out.”

Stage IV colorectal cancers

“If the colon or rectal cancer is stage IV, that means it spread to another organ, most commonly the liver or the lung,” Dr Maun said. “Unless the tumor is posing an imminent risk like a blockage or it's actively bleeding, these patients will start treatment with the medical oncologist, usually with chemotherapy only.”

Early Diagnosis Of Colorectal Cancers Matters

Dr. Maun emphasizes the importance of diagnosing colorectal cancers early – and that often starts with a colonoscopy.