Rectal cancer: causes, symptoms, diagnosis, treatment

This article is for informational purposes only and should not be considered medical advice. Please consult a qualified healthcare professional for personalized guidance and treatment.

What is rectal cancer and how it affects the colon

Rectal cancer begins in the cells lining the rectum and, because the rectum is part of the large intestine, it is closely linked to cancer that begins in the colon. Tumors may start as small polyps that over time can become malignant. The location in the rectum influences symptoms, surgical options, and how closely the cancer can be monitored. Treatment plans often take into account whether disease is limited to the rectum, involves nearby lymph nodes, or has spread to other organs.

Common symptoms: weight loss, fatigue, and bowel changes

Symptoms of rectal cancer can be subtle early on and more noticeable as disease progresses. Persistent changes in bowel habits, such as diarrhea or constipation, and a narrowing of stools may occur. Unexplained weight loss and ongoing fatigue are systemic signs that can accompany many cancers, including rectal cancer. Rectal bleeding or blood in the stool, a feeling of incomplete bowel emptying, and abdominal or pelvic pain are other common indicators that warrant medical evaluation.

Risk factors and causes of rectal cancer

No single cause explains every case of rectal cancer. Risk factors that increase likelihood include age (risk rises with advancing age), a personal or family history of colorectal polyps or colorectal cancer, certain inherited genetic syndromes, inflammatory bowel disease, and lifestyle factors such as diet, smoking, and physical inactivity. Having one or more risk factors does not mean a person will develop rectal cancer, but awareness can guide screening and prevention choices with a healthcare provider.

Diagnosis: tests and staging for rectal cancer

Diagnosing rectal cancer usually starts with a clinical evaluation and tests. A digital rectal exam and fecal occult blood tests may prompt further investigation. Colonoscopy is the primary diagnostic tool, allowing direct visualization and biopsy of suspicious areas. Imaging studies — such as pelvic MRI, CT scans, or endorectal ultrasound — assess the local extent of disease and whether lymph nodes or distant organs are involved. Pathology confirms cancer type and staging, which guides treatment decisions and prognosis discussions.

Treatment options and follow-up care

Treatment options depend on stage, location within the rectum, overall health, and patient preferences. Surgery is often a cornerstone of curative treatment for localized rectal cancer, with techniques ranging from local excision to more extensive resections that preserve bowel function when possible. Radiation therapy and chemotherapy may be used before surgery (neoadjuvant) to shrink tumors, after surgery (adjuvant) to reduce recurrence risk, or as primary therapy in select cases. For advanced disease, systemic therapies and targeted approaches can help control symptoms and prolong survival. Follow-up care typically includes regular physical exams, colonoscopic surveillance of the remaining colon, and periodic imaging to detect recurrence early.

Conclusion

Rectal cancer is a distinct form of colorectal cancer that requires careful evaluation of symptoms, timely diagnostic testing, and a treatment plan tailored to disease stage and patient needs. Familiarity with warning signs such as changes in bowel habits, rectal bleeding, unexplained weight loss, and fatigue can prompt earlier assessment. Decisions about screening, treatment, and follow-up are best made with a multidisciplinary medical team and individualized to the person’s circumstances.