What is Rectal Cancer?
Rectal cancer is a type of cancer that develops in the cells of the rectum, which is the last portion of the large intestine that connects to the anus. Like colon cancer, rectal cancer typically starts as small growths called polyps on the inner lining of the rectum. Over time, some of these polyps may become cancerous, forming tumors that can grow and potentially spread to other parts of the body if not detected and treated early.
Rectal cancer shares many similarities with colon cancer, including risk factors, symptoms, and treatment approaches. However, because of its location in the lower part of the digestive tract, rectal cancer may present with specific symptoms and require specialized treatment strategies.
Risk Factors for Rectal Cancer
Risk factors for rectal cancer include:
- Age: Risk increases with age, with most cases diagnosed in individuals over 50 years old.
- Family History: A family history of colorectal cancer or certain genetic syndromes (such as Lynch syndrome or familial adenomatous polyposis) increases the risk.
- Personal History: Previous colorectal cancer or certain types of polyps (such as adenomatous polyps) increases the risk of developing rectal cancer.
- Lifestyle Factors: Factors such as a diet high in red and processed meats, low-fiber diet, sedentary lifestyle, obesity, smoking, and heavy alcohol consumption may increase the risk.
- Inflammatory Bowel Disease: Chronic inflammatory conditions of the colon and rectum, such as ulcerative colitis or Crohn's disease, increase the risk of colorectal cancer, including rectal cancer.
Symptoms of Rectal Cancer
Symptoms of rectal cancer may include:
- Changes in Bowel Habits: Persistent diarrhea, constipation, or changes in the size, shape, or consistency of bowel movements.
- Rectal Bleeding: Blood in the stool (hematochezia) or bleeding from the rectum, which may appear as bright red blood on toilet paper or in the toilet bowl.
- Abdominal Discomfort: Persistent abdominal pain, cramping, or discomfort, often in the lower abdomen.
- Rectal Pain or Discomfort: Pain or discomfort in the rectum or anus, especially during bowel movements.
- Feeling of Incomplete Emptying: Sensation of incomplete emptying after bowel movements or a feeling of fullness in the rectum.
- Unexplained Weight Loss: Significant and unexplained weight loss, which may occur in advanced stages of the disease.
Diagnosis of Rectal Cancer
Rectal cancer is diagnosed through a combination of medical history, physical examination, endoscopic examination, imaging tests, and biopsy. Here's an overview of the diagnostic process:
Medical History: Your doctor will begin by taking a detailed medical history including any symptoms you may be experiencing and any risk factors you may have for colorectal cancer. This evaluation will also include discussion of cardiopulmonary health and comorbid medical conditions that may affect your treatment plan and surgical risk.
Physical Examination: In rectal cancer, physical examination provides valvuable information regarding the location and involvement of the tumor. This typically includes a digital rectal examination and proctoscopy in the office to precisely determine the location of the tumor and estimation of involvement of nearby structures.
Endoscopy: Colonoscopy is the gold standard for diagnosing rectal cancer. During a colonoscopy, a flexible, lighted tube with a camera (colonoscope) is inserted into the rectum and guided through the entire colon. This allows the doctor to directly visualize the inside of the rectum and colon, identify any abnormalities, and take tissue samples (biopsies) for further examination.
Biopsy: Diagnosis of rectal cancer is confirmed with biopsy of the rectal tumor – typically performed during colonoscopy.
CT scan: A computed tomography (CT) scan of the abdomen and pelvis may be performed to assess the extent of the cancer, evaluate nearby lymph nodes, and identify any spread to other organs.
MRI: Magnetic resonance imaging (MRI) is commonly be used to provide detailed images of the rectum and surrounding structures. This imaging study helps to determine the depth of tumor invasion into the rectal wall and evaluate nearby lymph nodes.
Endorectal Ultrasound: This imaging test uses sound waves to create images of the rectum and nearby structures. This endoscopic procedure can help assess the depth of tumor invasion into the rectal wall and evaluate nearby lymph nodes.
Laboratory Tests: Blood tests may be performed to assess levels of certain tumor markers, such as carcinoembryonic antigen (CEA), which can be elevated in individuals with colorectal cancer. While these tests are not used alone to diagnose cancer, they can provide additional information to support the diagnosis and monitor treatment response.
Staging for Rectal Cancer
Rectal cancer staging is a process used to determine the extent of the cancer and how far it has spread within the rectum and to other parts of the body. Staging is crucial for guiding treatment decisions and predicting prognosis. The most commonly used staging system for rectal cancer is the TNM staging system, which classifies tumors based on three key factors: the size and extent of the primary tumor (T), the involvement of nearby lymph nodes (N), and the presence of distant metastases (M).
In addition to the TNM staging system, other factors such as tumor grade, tumor location, and the patient's overall health and medical history may also influence treatment decisions and prognosis.
Multidisciplinary Care in Rectal Cancer
The treatment of rectal cancer typically involves a multidisciplinary approach, meaning that it requires coordination and collaboration among various healthcare professionals from different specialties to provide comprehensive care. A multidisciplinary team (MDT) approach ensures that patients receive individualized treatment plans that consider all aspects of their condition, including the stage of the cancer, the patient's overall health and preferences, and the expertise of the medical team.
Key members of the multidisciplinary team involved in the treatment of rectal cancer may include:
- Colorectal Surgeon: Specializes in surgical procedures for the treatment of colorectal conditions, including rectal cancer. Your Colorectal Surgeon will work closely with the multidisciplinary team members to develop consensus around a treatment plan and coordinate care throughout your treatment course.
- Medical Oncologist: Specializes in the use of chemotherapy, targeted therapy, and immunotherapy to treat cancer. Medical oncologists develop and oversee chemotherapy treatment plans for patients with rectal cancer, either before or after surgery.
- Radiation Oncologist: Specializes in the use of radiation therapy to treat cancer. Radiation oncologists develop and oversee radiation treatment plans for patients with rectal cancer, typically in combination with chemotherapy.
- Gastroenterologist/Endoscopist: Specializes in performing endoscopic procedures, such as colonoscopy and sigmoidoscopy, for the diagnosis and staging of rectal cancer.
- Pathologist: Specializes in the examination of tissue samples (biopsies) to diagnose cancer and determine its characteristics, such as tumor type, grade, and stage. Pathologists play a critical role in providing accurate and timely diagnostic information to guide treatment decisions.
- Radiologist: Specializes in the interpretation of imaging tests, such as CT scans, MRI scans, and PET scans, to assess the extent of the cancer and identify any spread to nearby lymph nodes or distant organs.
- Nurse Navigator or Coordinator: Helps coordinate care, provide support, and guide patients through the treatment process. Nurse navigators or coordinators serve as a point of contact for patients and help ensure that they receive timely and appropriate care. comprehensive, coordinated, and personalized care throughout the course of their treatment for rectal cancer.
Diagnosing Rectal Cancer
The colorectal surgeon will conduct a thorough evaluation, which may include reviewing the patient's medical history, performing a physical examination (including a digital rectal examination), and ordering diagnostic tests such as colonoscopy, sigmoidoscopy, imaging scans (such as CT or MRI), and biopsy. The goal is to accurately diagnose the extent and stage of the rectal cancer.
Treatment of Rectal Cancer
Determining a treatment plan depends on several factors including the stage of the cancer, the location and size of the tumor, the patient's overall health and preferences, and the expertise of the medical team. Treatment may involve a combination of surgery, radiation therapy, chemotherapy, targeted therapy, and immunotherapy.
Surgery
- Transanal Excision: This minimally invasive procedure is used for early-stage rectal cancer that has not spread beyond the inner layers of the rectum. The tumor is removed through the anus using specialized instruments. This technique is possible for low tumors within 8 cm of the anal opening.
- Transanal Minimally Invasive Surgery (TAMIS): TAMIS is a minimally invasive procedure used for early-stage rectal cancer that has not spread beyond the inner layers of the rectum. This technique is possible for mid-rectal tumors located between 5 and 15 cm from the anal opening.
- Low Anterior Resection (LAR): In this procedure, the portion of the rectum containing the tumor is removed, and the colon is reattached to the remaining healthy rectum. LAR is typically used for tumors without involvement of the anorectal sphincter muscles.
- Abdominoperineal Resection (APR): APR involves removing the entire rectum, anus, and surrounding tissues through incisions made in the abdomen and perineum. This procedure may be necessary for tumors located in the lower part of the rectum or for advanced cancers involving the anorectal sphincter muscles
Radiation Therapy: For some patients with locally advanced rectal cancer, high-energy X-rays are directed at the tumor and surrounding tissues from outside the body to destroy cancer cells and shrink the tumor. This treatment improves the success rate for surgery and reduces the risk of recurrence.
Chemotherapy: Chemotherapy may be used before surgery (neoadjuvant chemotherapy) to shrink the tumor and make it easier to remove, or after surgery (adjuvant chemotherapy) to kill any remaining cancer cells and reduce the risk of recurrence.
Targeted Therapy: Specialized medications may be used to target specific molecules or pathways involved in the growth and spread of cancer cells, particularly in tumors with specific genetic mutations (such as KRAS or BRAF mutations).
Immunotherapy: Specialized medications may be used to stimulate the immune system to recognize and attack cancer cells, particularly in tumors with high levels of microsatellite instability (MSI-H) or mismatch repair deficiency (dMMR).
What to Expect Following Rectal Cancer Treatment
Following treatment, the colorectal surgeon will provide ongoing monitoring and follow-up care to monitor the patient's progress, assess for any signs of recurrence, and address any postoperative issues or complications. The surgeon will work closely with other members of the multidisciplinary team to ensure comprehensive and coordinated care throughout the patient's journey.
Overall, patients can expect compassionate, patient-centered care from a colorectal surgeon who is dedicated to achieving the best possible outcomes for individuals with rectal cancer.