Overview

Rectal cancer is a type of colorectal cancer that develops in the rectum, the final section of the large intestine before the anus. It usually develops from abnormal cells or polyps in the inner lining of the rectum and may grow into surrounding tissues or spread to nearby lymph nodes and distant organs if left untreated. Rectal cancer is different from colon cancer because of its location, and treatment planning can therefore differ considerably.

Common symptoms include rectal bleeding, blood in the stool, changes in bowel habits, abdominal or pelvic discomfort, and a feeling that the bowel has not completely emptied. Some patients may not experience noticeable symptoms during the early stages.

At Sarvodaya Hospital, our multidisciplinary cancer care team provides comprehensive rectal cancer treatment based on the tumour's stage, location, size, molecular characteristics, and the patient's overall health. Treatment may include surgery, chemotherapy, radiation therapy, targeted therapy, immunotherapy, or a combination of these approaches.

Symptoms of Rectal Cancer

• Rectal bleeding
• Blood in the stool
• Persistent change in bowel habits
• Diarrhoea or constipation
• Narrow stools
• A feeling that the bowel has not completely emptied
• Increased urgency to pass stool
• Pelvic or abdominal discomfort
• Pain during bowel movements
• Unexplained weight loss
• Persistent fatigue or weakness
• Iron-deficiency anaemia
• Reduced appetite

Causes of Rectal Cancer

• Increasing age
• Previous colorectal polyps
• Family history of colorectal cancer
• Inherited conditions such as Lynch syndrome
• Familial adenomatous polyposis
• Inflammatory bowel disease
• Obesity
• Physical inactivity
• Smoking
• Heavy alcohol consumption
• Diet high in processed or red meat
• Previous colorectal cancer

Risk Factors for Rectal Cancer

Certain factors can increase the likelihood of developing rectal cancer.

• Increasing Age : The risk of colorectal cancer generally increases with age, although rectal cancer can also affect younger adults.
• Family History : Having a close family member with colorectal cancer or certain types of polyps can increase risk.
• Genetic Conditions : Inherited conditions such as Lynch syndrome and familial adenomatous polyposis significantly increase the risk of colorectal cancer.
• Inflammatory Bowel Disease : Long-standing ulcerative colitis or Crohn's disease involving the colon or rectum can increase cancer risk.
• Previous Polyps : Certain adenomatous or other high-risk polyps can develop into cancer over time.
• Lifestyle Factors : Obesity, physical inactivity, smoking, heavy alcohol consumption, and certain dietary patterns may increase risk.
• Previous Radiation : Previous radiation exposure involving the pelvic area may increase the risk of developing certain cancers.

Diagnosis of Rectal Cancer

Accurate diagnosis helps confirm the cancer, assess its local extent, identify whether it has spread, and guide treatment planning.

• Digital Rectal Examination : A doctor may examine the rectum manually to identify abnormalities, masses, bleeding, or changes in the rectal wall.
• Colonoscopy : Colonoscopy allows the doctor to examine the entire colon and rectum using a flexible camera. Suspicious lesions can be biopsied during the procedure.
• Rectal Biopsy : A biopsy provides tissue for pathological examination and confirms whether cancer cells are present.
• MRI of the Pelvis : Pelvic MRI is an important investigation for rectal cancer because it provides detailed information about the tumour's location, depth of invasion, nearby lymph nodes, and surrounding structures.
• CT Scan : CT imaging may be used to assess the chest, abdomen, and pelvis for evidence of cancer spread.
• PET-CT : PET-CT may be recommended in selected situations when additional information about suspected metastatic or recurrent disease is required.
• Molecular and Biomarker Testing : Tumour tissue may undergo molecular testing, including assessment of mismatch repair or microsatellite instability, to help guide systemic treatment decisions.

Treatment Options for Rectal Cancer

The most appropriate rectal cancer treatment depends on the tumour stage, location, size, relationship with the anal sphincter, molecular characteristics, and overall health of the patient.

● Chemotherapy and Radiation Therapy Before Surgery : For many locally advanced rectal cancers, treatment may begin with chemotherapy, radiation therapy, or a combination of both before surgery.

● Rectal Cancer Surgery : Surgery is an important part of treatment for many patients with localised or locally advanced rectal cancer. The specific procedure depends on tumour location and whether the anal sphincter can safely be preserved.

● Low Anterior Resection (LAR) : Removes the section of the rectum containing the tumour along with nearby lymph nodes and surrounding tissue when required. The remaining bowel is then connected to the remaining rectum or anus when medically appropriate.

● Abdominoperineal Resection (APR) : Removes the rectum, anus, and anal sphincter. It is generally recommended when the tumour is very close to or involves  the anal sphincter and sphincter preservation is not considered oncologically safe.

● Laparoscopic Rectal Cancer Surgery : A minimally invasive approach performed through small incisions using specialised instruments and a camera. In appropriately selected patients, it can reduce incision size and may support reduced post-operative discomfort and faster recovery. 

Benefits of Early Rectal Cancer Treatment

Early diagnosis and timely colorectal cancer treatment can provide several important benefits.

• Allows Timely Treatment : Early diagnosis allows the cancer team to begin treatment before the disease progresses further.
• Improves Surgical Options : When the tumour is diagnosed before extensive spread, surgery may offer a greater possibility of complete tumour removal.
• May Support Sphincter Preservation : In selected patients, appropriate pre-operative treatment can reduce tumour size and may allow sphincter-saving surgery when clinically safe.
• Reduces Risk of Complications : Timely treatment can help prevent complications such as bowel obstruction, bleeding, severe pain, and nutritional problems.
• Supports Better Long-Term Outcomes : Early-stage rectal cancer generally has more treatment options and may have better outcomes than advanced disease.

Complications if Left Untreated

• Persistent rectal bleeding
• Iron-deficiency anaemia
• Bowel obstruction
• Severe constipation
• Increasing pelvic or abdominal pain
• Difficulty passing stool
• Bowel perforation in advanced cases
• Spread to nearby lymph nodes
• Liver metastasis
• Lung metastasis
• Reduced nutritional status
• Need for more complex treatment

When Should You See a Doctor?

Consult a rectal cancer specialist or colorectal specialist if you experience:

• Rectal bleeding
• Blood in the stool
• Persistent changes in bowel habits
• Unexplained weight loss
• Persistent abdominal or pelvic pain
• Narrow stools
• A feeling of incomplete bowel emptying
• Persistent fatigue
• Unexplained anaemia
• A family history of colorectal cancer
• Symptoms that continue despite routine treatment

Prevention & Lifestyle Modifications

Certain lifestyle measures can help reduce colorectal cancer risk and support overall health.

• Maintain a Healthy Weight : Maintaining a healthy weight can help reduce the risk associated with obesity.
• Stay Physically Active : Regular physical activity supports healthy bowel function and overall health.
• Follow a Balanced Diet : Include vegetables, fruits, whole grains, pulses, and other fibre-rich foods in your diet.
• Limit Processed and Red Meat : Reducing processed meat and moderating red meat intake may help reduce colorectal cancer risk.
• Avoid Tobacco : Not smoking reduces the risk of several cancers, including colorectal cancer.
• Limit Alcohol : Limiting alcohol consumption supports overall health and may reduce cancer risk.

Pre- and Post-Treatment Care

Pre-Treatment

• Surgical oncology consultation
• Medical oncology consultation
• Radiation oncology consultation
• Colonoscopy and biopsy
• Pelvic MRI
• CT scan
• PET-CT when indicated
• Molecular and biomarker testing
• Blood investigations
• Nutritional assessment
• Anaesthesia evaluation before surgery
• Multidisciplinary treatment planning

Post-Treatment

• Prescribed medications
• Wound and incision care
• Stoma care when applicable
• Gradual return to physical activity
• Dietary and nutritional guidance
• Pelvic floor rehabilitation when appropriate
• Bowel function management
• Regular oncology follow-up
• Recommended colonoscopy and imaging
• Monitoring for recurrence
• Psychological and emotional support