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Overview

What Is Rectal Cancer?

Rectal cancer is abnormal cell growth that begins in the rectum, the final part of the large intestine before the anus. It is part of colorectal cancer, a broader term that includes cancers of the colon and rectum. Rectal cancer can affect adults of different ages, although the risk generally increases with age. The location of the tumor helps guide testing and treatment.

Symptoms

Rectal Cancer Symptoms

Early rectal cancer may cause no noticeable symptoms. Persistent or worsening bowel changes should be assessed by a healthcare professional, even when they seem mild or have another possible explanation. The symptoms of rectal cancer can also occur with noncancerous conditions.

  • Rectal bleeding or blood in the stool can occur with rectal cancer.
  • A persistent change in bowel habits, such as new diarrhea, constipation, or changes in frequency, should be assessed.
  • Stools may become narrower than usual.
  • A feeling of incomplete bowel emptying may occur after a bowel movement.
  • Unexplained weight loss can be a warning sign.
  • Abdominal or pelvic discomfort may develop.
  • Fatigue may result from the cancer or from anemia caused by bleeding.
  • Changes in bowel control, including urgency or leakage, may occur.

WHEN SYMPTOMS NEED ATTENTION

Get persistent bowel changes checked

Rectal bleeding, bowel leakage, or changes in stool do not by themselves confirm cancer, but they should not be self-diagnosed or ignored. Arrange a medical evaluation if symptoms persist, recur, or worsen.

Causes

What Causes Rectal Cancer?

Rectal cancer begins when genetic changes disrupt the normal controls that regulate cell growth and repair. Abnormal cells can multiply and form a tumor in the rectal lining. In many cases, a single cause cannot be identified, and having a risk factor does not mean that cancer will develop.

Risk Factors

Risk Factors for Rectal Cancer

  • Older age is associated with a higher likelihood of colorectal cancer, although younger adults can also develop it.
  • A personal history of colorectal cancer or polyps can increase future risk.
  • A family history of colorectal cancer or advanced polyps can increase risk.
  • Inherited syndromes, including Lynch syndrome and familial adenomatous polyposis, can substantially increase risk.
  • Inflammatory bowel disease, including ulcerative colitis and Crohn’s disease affecting the colon, can increase risk over time.
  • Previous radiation treatment to the pelvis may increase the later risk of rectal cancer.
  • Smoking is associated with a higher risk of colorectal cancer and other cancers.
  • Regular or heavy alcohol use can contribute to colorectal cancer risk.
  • Excess body weight is associated with a higher likelihood of colorectal cancer.
  • Physical inactivity is associated with increased colorectal cancer risk.
  • Dietary patterns high in processed meat and low in fiber-rich plant foods are associated with colorectal cancer risk.
Risk-factor typeExamplesWhat readers should know
Non-modifiableAge, family history, inherited conditions, and prior colorectal polyps or cancerThese factors cannot usually be changed, but they may affect when screening should begin and how often it is needed.
Medical historyInflammatory bowel disease and prior pelvic radiationDiscuss the timing and type of screening or surveillance with the clinician managing your condition.
Modifiable or partly modifiableTobacco, alcohol, physical inactivity, excess weight, and dietary patternsChanging these factors may reduce risk, although it cannot eliminate the possibility of colorectal cancer.

Complications

Rectal Cancer Complications

  • A growing tumor can narrow the bowel and cause a bowel obstruction.
  • Ongoing or worsening bleeding can lead to anemia.
  • Anemia may cause fatigue, weakness, shortness of breath, or dizziness.
  • Rectal cancer can cause pelvic, abdominal, or other pain.
  • Tumor growth or treatment can contribute to changes in bowel control.
  • The cancer may spread to nearby tissues or lymph nodes.
  • Advanced cancer may spread to distant organs such as the liver or lungs.
  • Treatment can contribute to nutritional problems or changes in bowel and other body functions.

SEEK URGENT CARE

Possible signs of a serious complication

Seek urgent medical help for heavy or persistent bleeding, severe abdominal swelling or pain, repeated vomiting, inability to pass stool or gas, fainting, or sudden severe weakness.

Diagnosis & Staging

Diagnosis and Staging of Rectal Cancer

Evaluation may include a medical history, physical examination, and rectal examination. Blood tests can check for anemia and other health information, while colonoscopy or sigmoidoscopy allows a specialist to view the bowel and take a biopsy. Imaging, such as pelvic MRI or CT, helps assess the tumor and look for lymph-node or distant spread.

How clinical staging guides care

StageGeneral meaningHow it informs care
Stage 0Abnormal cells are limited to the innermost lining and have not invaded deeper tissue.Local removal or another focused treatment may be considered in selected cases.
Stage IThe tumor has invaded the rectal wall but has not reached nearby lymph nodes or distant organs.Treatment generally focuses on controlling or removing the localized tumor.
Stage IIThe tumor has grown through the rectal wall or into nearby tissues without nearby lymph-node involvement.The care team may combine local and systemic treatments based on tumor features.
Stage IIIThe cancer has spread to nearby lymph nodes but not to distant organs.Treatment commonly includes a combination of therapies to reduce local and distant recurrence risk.
Stage IVThe cancer has spread to distant organs or distant sites.Treatment focuses on controlling the cancer, relieving symptoms, and supporting quality of life; options depend on tumor biology and overall health.

Treatment Options

Rectal Cancer Treatment Options

Rectal cancer treatment may involve a combination of therapies. A colorectal surgeon, medical oncologist, radiation oncologist, radiologist, pathologist, and other specialists may contribute to the care plan. Recommendations depend on the stage, tumor location and biology, overall health, and personal preferences.

LOCAL TREATMENT

Surgery: Surgery removes the tumor and nearby tissue when appropriate. Depending on the operation and the location of the tumor, a temporary or permanent ostomy may be needed.

Radiation therapy: Radiation may be used before or after surgery, or to control symptoms or cancer that cannot be removed completely.

SYSTEMIC TREATMENT

Chemotherapy: Chemotherapy may be given before or after surgery or used for advanced disease. It travels through the bloodstream to treat cancer cells in different areas.

Targeted therapy: Molecular testing may identify treatments aimed at specific features of some advanced tumors.

SELECTED APPROACHES

Immunotherapy: Some tumors have features that make them more likely to respond to medicines that help the immune system recognize cancer cells.

Active surveillance or local treatment: Carefully selected early cancers may be managed with close monitoring or a focused local procedure when clinically appropriate.

TREATMENT DECISIONS

Your care plan should be individualized

Ask your care team about treatment goals, possible side effects, fertility, bowel function, sexual health, and ostomy support. Treatment plans differ according to stage, tumor biology, overall health, and personal priorities.

Prevention & Screening

Rectal Cancer Prevention and Screening

Colorectal cancer screening can detect precancerous polyps or cancer before symptoms appear. Recommendations vary according to age, personal history, family history, inherited risk, and inflammatory bowel disease. People with symptoms need diagnostic evaluation rather than relying on routine screening alone.

  • Avoiding tobacco can reduce colorectal cancer risk and improve overall health.
  • Limiting alcohol can help reduce colorectal cancer risk.
  • Regular physical activity supports a lower-risk lifestyle.
  • Maintaining a healthy weight may reduce colorectal cancer risk.
  • Eating a balanced dietary pattern with fiber-rich foods, vegetables, fruits, legumes, and whole grains may support colorectal health.
  • Discuss inherited risk or inflammatory bowel disease with a clinician because earlier or more frequent screening may be needed.

SCREENING MATTERS

Ask when screening should begin

Follow current local colorectal cancer screening guidance and ask when screening should begin for you. People with symptoms or increased risk may need diagnostic tests or a tailored surveillance plan instead of routine screening alone.

Outlook and Prognosis

Outlook and Prognosis for Rectal Cancer

The outlook for rectal cancer depends on the stage, tumor biology, response to treatment, and overall health. It also depends on whether the cancer can be completely removed or controlled. Your oncology team can interpret test results and treatment response more accurately than a general survival estimate.

Stage-based

Survival estimates are generally reported by the extent of disease rather than as one rate for every person.

Population data

Registry statistics describe groups of people treated during an earlier period and may not reflect current therapies.

Colon and rectal cancer

Combined colorectal or colon cancer statistics may not exactly represent outcomes for rectal cancer.

Survivorship & Follow-up

Survivorship and Follow-Up After Rectal Cancer

Follow-up after rectal cancer usually includes scheduled visits, physical assessments, blood tests when appropriate, colonoscopy, and imaging based on the original cancer and treatment plan. The schedule is individualized according to recurrence risk, treatment, symptoms, and overall health. Contact the care team about new or persistent symptoms between visits.

  • Recurrence monitoring may include appointments, examinations, blood tests, colonoscopy, or imaging.
  • Bowel and bladder function should be discussed when symptoms affect daily life.
  • People with an ostomy may need ongoing stoma care and access to an ostomy specialist.
  • Nutrition support can help address appetite changes, weight changes, or bowel symptoms.
  • Physical activity can support recovery when it is safe for your health and treatment status.
  • Fatigue may continue after treatment and should be reported if it is severe or worsening.
  • Sexual health concerns can be discussed with the oncology or primary care team.
  • Fertility concerns should be addressed before treatment when possible and revisited during survivorship care.
  • Emotional well-being matters, and counseling or support groups may help with distress or adjustment.
  • New bleeding, bowel changes, pain, weight loss, or other concerning symptoms should be communicated to the care team.

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