What Is Rectal Cancer?

Rectal cancer develops in the rectum, the final portion of the large intestine. It is one of the most common cancers worldwide and is highly treatable when detected early.

Before developing an individualized treatment plan, your healthcare team will determine the extent (stage) of the disease using:

• Magnetic Resonance Imaging (MRI)
• Endoscopic ultrasound
• Computed Tomography (CT) scan
• Blood tests

These studies help clinically stage the tumor. Treatment decisions are based on tumor size, depth of invasion, lymph node involvement, and whether cancer has spread to other organs.

Treatment may involve surgery, chemotherapy, radiation therapy, or a combination of these approaches.

Stage 0: Rectal Cancer Treatment

Stage 0 cancer is confined to the inner lining of the rectum.

Treatment typically involves minimally invasive surgical removal. Additional therapies are usually not required.

Stage I: Rectal Cancer Treatment

Stage I tumors have grown into the rectal wall but have not spread outside the rectum.

Most Stage I cancers are treated with surgery. When possible, minimally invasive techniques are used.

Common Surgical Options

• Local transanal excision: Removal of early-stage cancers through the anus without abdominal incisions.
• Transanal endoscopic surgery: Used for larger tumors located higher in the rectum.

If the tumor cannot be safely removed through the rectum, abdominal surgery may be required:

• Anterior resection: Removal of the tumor with reconnection of the colon to the remaining rectum.
• Low anterior resection (LAR): Removal of the rectum with reconnection of the colon to the anus (coloanal anastomosis).
• Abdominoperineal resection (APR): Removal of the rectum, anus, and sphincter muscles. This requires a permanent colostomy.

Your surgeon will discuss sphincter-sparing options whenever possible.

Stage II and Stage III Rectal Cancer Treatment

Stage II cancer has grown through the rectal wall but has not spread to lymph nodes.

Stage III cancer has spread to nearby lymph nodes.

Most Stage II and III cancers are treated with a combination of:

• Chemotherapy
• Radiation therapy
• Surgery

Preoperative (Neoadjuvant) Therapy

Radiation therapy, often combined with chemotherapy, is frequently given before surgery to:

• Shrink the tumor
• Improve surgical outcomes
• Reduce the need for permanent colostomy

Common chemotherapy medications include:

• Fluorouracil (5-FU)
• Leucovorin
• Oxaliplatin
• Capecitabine

Radiation may be delivered over 5–6 weeks in smaller doses or over a shorter course in higher doses, depending on individual factors.

Surgery

After neoadjuvant therapy, imaging studies are repeated to assess tumor response. Surgical options depend on tumor location and response to therapy.

Postoperative Chemotherapy

Most patients receive additional chemotherapy for 5–6 months after surgery to reduce recurrence risk.

Colostomy and Ileostomy

A colostomy brings the colon to an opening in the abdominal wall when the rectum is removed.

An ileostomy temporarily diverts stool through the small intestine to allow healing after surgery.

Some ostomies are temporary; others may be permanent depending on the surgical procedure.

Your care team will provide detailed education and support if an ostomy is required.

Stage IV Rectal Cancer Treatment

Stage IV rectal cancer has spread to distant organs such as the liver or lungs.

Treatment usually includes:

• Chemotherapy
• Targeted therapy
• Radiation therapy
• Surgery (when appropriate)

Chemotherapy is often the first step to control disease spread. If tumors shrink sufficiently, surgery may become an option.

Common medications include:

• 5-FU
• Oxaliplatin
• Capecitabine
• Irinotecan
• Bevacizumab
• Cetuximab
• Panitumumab

If surgery is not possible, treatment focuses on symptom control and slowing cancer progression.

Recurrent Rectal Cancer

Rectal cancer may return locally or in distant organs.

Local Recurrence

Often treated with surgery, sometimes combined with radiation or chemotherapy.

Distant Recurrence

Managed with chemotherapy, targeted therapy, and surgery when feasible.

Because recurrent disease can be complex, care at a specialized colorectal center is recommended.

Post-Treatment Care and Follow-Up

Regular follow-up is essential after treatment.

Monitoring may include:

• Physical examinations
• Blood tests
• Imaging studies
• Colonoscopy

Early detection and appropriate treatment significantly improve long-term outcomes.

If you have been diagnosed with rectal cancer or have symptoms such as rectal bleeding or changes in bowel habits, timely evaluation by a colorectal specialist is essential.