Rectal Cancer Treatment

Rectal cancer originates in the rectum, the lower segment of the large intestine where stool is stored before being expelled from the body through the anus. In many cases, the tumor develops from abnormal growths (polyps) in the rectal lining. Although polyps are common and initially benign, they can gradually progress and become cancerous if left untreated. This underscores the importance of early detection through routine screening tests, such as colonoscopy.

Although the exact cause of rectal cancer remains unclear, certain factors are known to increase the risk. These include tobacco use, a sedentary lifestyle, a deficiency in dietary fiber and a family history of colorectal cancer. Common symptoms include blood in the stool, persistent changes in bowel habits, abdominal discomfort and unexplained weight loss.

After diagnosing rectal cancer, the physician will stage the tumor using imaging tests, such as computed tomography (CT) scans of the chest, abdomen and pelvis, as well as magnetic resonance imaging (MRI) scans of the rectum. Treatment can vary based on the extent of the tumor and may involve a combination of radiation therapy, chemotherapy and surgery.

Radiation therapy for rectal cancer

Radiation therapy is a key treatment option for rectal cancer, often used in combination with surgery and chemotherapy. It involves using high-energy beams to target and destroy cancerous cells in the rectum.

Types of radiation therapy for rectal cancer

The specific approach to radiation therapy for rectal cancer can vary depending on the stage of the tumor and the patient’s overall health. The types include:

• External beam radiation therapy (EBRT) – EBRT is the most common form of radiation therapy for rectal cancer. An external machine (linear accelerator) delivers targeted beams to the tumor while minimizing exposure to the surrounding healthy tissues.
• Internal radiation therapy (brachytherapy) – Brachytherapy involves surgically placing a small radiation source directly inside or near the tumor. This treatment approach may be an option for a patient who is not a candidate for rectal cancer surgery or requires targeted treatment for a localized rectal tumor.

How is radiation therapy used for rectal cancer?

To address rectal cancer, radiation therapy may be used:

• Before surgery – Radiation therapy is often combined with chemotherapy to shrink a tumor, which can make it easier to remove during surgery or eliminate the need for surgery altogether. This approach can be particularly beneficial for locally advanced rectal cancer.
• After surgery – In some cases, radiation therapy may be used post-surgery to eliminate any remaining microscopic cancer cells and reduce the risk of recurrence.
• As a primary treatment – For a patient who cannot undergo surgery due to advanced rectal cancer or a co-existing health condition, radiation therapy may be used to help control tumor growth and alleviate symptoms.
• For supportive care – In cases of rectal cancer spread, radiation therapy can help relieve the associated symptoms, such as pain, bleeding and bowel obstruction.

Potential side effects of radiation therapy for rectal cancer

While radiation therapy can be effective for rectal cancer, it may cause side effects, which can vary depending on the radiation dosage, treatment duration and patient’s overall health. Most side effects of radiation therapy are temporary and can be managed with supportive care. Some patients experience:

• Fatigue
• Skin irritation in the treatment area
• Changes in bowel habits, such as diarrhea or urgency
• Rectal discomfort or irritation
• Nausea
• Difficulty controlling bowel movements

Chemotherapy for rectal cancer

Chemotherapy is an essential treatment option for rectal cancer, often used alongside surgery and radiation therapy for heightened effectiveness. As a systemic treatment, chemo involves the use of powerful cancer-fighting drugs that enter the bloodstream and travel throughout the body to target rapidly dividing cells, either destroying them directly or preventing them from growing and dividing.

How is chemotherapy used for rectal cancer?

The role of chemotherapy in rectal cancer treatment can vary depending on the stage of the tumor and the patient’s overall health. Chemo may be used:

• Before surgery – In cases of locally advanced rectal cancer (stages 2 and 3), chemotherapy is often combined with radiation therapy (chemoradiation) to shrink the tumor, making it easier to surgically remove.
• After surgery – To reduce the risk of recurrence (especially if rectal cancer has spread to lymph nodes), chemotherapy can be used to eliminate microscopic cancer cells that were not removed during surgery.
• As a primary treatment for advanced or metastatic cancer – If the tumor has spread beyond the rectum to distant organs, such as the liver or lungs, chemotherapy may be used to slow the progression of the cancer and relieve the associated symptoms.

Common chemotherapy drugs for rectal cancer

Several chemo drugs may be used to treat rectal cancer, either alone or in combination. These include:

• Fluorouracil (5-FU) – A common chemotherapy drug, 5-FU is often given with leucovorin, a vitamin that can boost its effectiveness.
• Capecitabine (Xeloda®) – An oral chemotherapy drug, Xeloda converts into 5-FU once inside the body.
• Oxaliplatin (Eloxatin®) – For heightened efficacy, Eloxatin may be combined with 5-FU and leucovorin in a chemotherapy regimen known as FOLFOX.
• Irinotecan (Camptosar®) – Sometimes, Camptosar is used in combination therapies for advanced or recurrent rectal cancer.

Potential side effects of chemotherapy for rectal cancer

Chemo can be effective for rectal cancer. However, this powerful systemic treatment can affect rapidly dividing cells throughout the body. Therefore, in addition to cancerous cells, it may damage healthy cells that naturally divide rapidly, such as cells in the skin, blood cells in the bone marrow and cells lining the gastrointestinal tract. This can lead to side effects, which can vary based on the specific drugs used, dosage and individual response to treatment.

Common side effects of chemotherapy for rectal cancer include:

• Fatigue
• Nausea and vomiting
• Diarrhea
• Loss of appetite
• Increased risk of infection due to low white blood cell counts
• Hair thinning or loss
• Numbness and tingling in hands and feet (neuropathy)

Most side effects of chemo for rectal cancer are temporary and can be managed with medication and supportive care.

Surgery for rectal cancer

Surgery is the primary treatment for rectal cancer, especially when the tumor is localized. The goal is to remove the cancerous tissues while preserving as much bowel function as possible. Because the rectum is located deep within the pelvis, rectal cancer surgery is generally more complex than colon cancer surgery.

Types of surgery for rectal cancer

The precise surgical technique used to treat rectal cancer can vary depending on the size and location of the tumor and whether it has spread to nearby lymph nodes or organs. Options may include:

• Local excision – Transanal excision or transanal endoscopic microsurgery (TEM) may be suitable for a small, early-stage tumor that has not spread beyond the rectal wall. The surgeon will remove the tumor and a slim margin of surrounding healthy tissue through the anus without making an external incision.
• Low anterior resection (LAR) – LAR may be performed to address a tumor in the upper or middle rectum. After removing the affected portion of the rectum, the surgeon will connect the remaining healthy portion of the rectum to the colon, allowing for normal bowel function.
• Abdominoperineal resection (APR) – APR may be a good option for a tumor in the lower rectum, near the anus. After removing the entire rectum and anus, the surgeon will create an opening in the abdomen to allow waste to exit the body into a colostomy bag. A permanent colostomy will be necessary if the anal sphincter cannot be preserved.
• Total mesorectal excision (TME) – Often performed alongside LAR or APR, TME is a standard surgical technique for rectal cancer that involves removing the entire rectum and surrounding lymph nodes to reduce the risk of recurrence.
• Pelvic exenteration – If rectal cancer has spread from the rectum to a nearby organ, such as the bladder or uterus, the surgeon will remove the rectum and affected organ. Reconstructive surgery may be needed to restore urinary or reproductive function.

In certain cases, rectal cancer surgery can be performed using laparoscopic (keyhole) or robotic-assisted techniques, which involve smaller incisions, less blood loss and a faster recovery compared to traditional open surgery.

Recovery and potential side effects of rectal cancer surgery

The healing process after rectal cancer surgery can vary depending on the type of procedure performed and the patient’s overall health. Possible side effects include:

• Pain, discomfort or infection at the surgical site
• Excessive bleeding and blood clots
• Changes in bowel habits, such as increased frequency or urgency
• Difficulty controlling bowel movements (fecal incontinence)
• Need for a temporary or permanent colostomy

Care and follow-up after rectal cancer surgery

After surgery, the patient may require additional treatment, such as radiation therapy or chemotherapy, to eliminate any remaining microscopic cancer cells and reduce the risk of recurrence. From there, the patient will be monitored through regular follow-up visits, imaging scans and colonoscopies.

Frequently asked questions (FAQs) about rectal cancer treatment

The following FAQs-related article provides additional information about rectal cancer treatment:

• What are the risks of rectal cancer surgery?

Benefit from world-class care at Moffitt Cancer Center

In Moffitt’s nationally acclaimed Gastrointestinal Oncology Program, our patients can benefit from a comprehensive range of rectal cancer treatment options in a single, convenient location. Our team provides the latest surgical and nonsurgical therapies, as well as novel treatments made possible through our robust clinical trials portfolio.

We also offer specialized therapies to help control the symptoms of large or obstructive rectal tumors. For instance, we may suggest balloon dilation if a tumor is preventing stool from passing properly through the digestive tract, or we can prescribe medication to alleviate persistent constipation or diarrhea. Provided alongside potentially curative strategies, these therapies help our patients achieve the best possible quality of life regardless of which treatment approach they choose.

If you would like to learn more about rectal cancer treatment, you can request an appointment with a specialist in Moffitt’s Gastrointestinal Oncology Program by calling 1-888-663-3488 or submitting a new patient registration form online. We do not require referrals.