WHAT IS RECTAL CANCER?
Abnormal and unrestricted growth of tissue of the rectum which tends to invade the adjacent structures and spread through lymph and blood. It grows into a mass/ tumour, as an ulcer or as a constricting ring in the lumen. It can arise from any component of tissue, however commonest one is adenocarcinoma which arises from the glands of the lining.
WHO IS AT RISK OF GETTING RECTAL CANCER?
The major risk factor for rectal cancer are certain types of precancerous polyps. This cancer is often inheritable and can run in families. Such syndromes are:
Classic or attenuated Familial Adenomatous Polyposis (FAP/aFAP)
Hereditary non polyposis colorectal cancer or Lynch syndrome
Juvenile polyposis syndrome
Peutz Jeghers syndrome
Certain risk factors identified in non-inheritable cases long standing ulcerative colitis, obesity, high consumption in processed foods and processed meats, smoking, alcohol abuse. Early cancer may have no signs of symptoms and may be detected incidentally.
WHAT ARE THE SYMPTOMS OF RECTAL CANCER?
Blood in stools/ black tarry stools/ Changing bowel habits
Unexplained weight loss
Emergency presentation : Signs of intestinal obstruction or perforation of intestine
Lump in abdomen/ Abdominal distension
Early rectal cancer may have no signs or symptoms. Some may be diagnosed incidentally during endoscopy.
WHAT ARE THE TESTS TO DIAGNOSE RECTAL CANCER?
Colonoscopy and biopsy: This entails visualising the entire colon from within and taking specimen from any suspicious areas for pathological testing.
Studies to decide stage of cancer: magnetic resonance imaging (MRI), Computed Tomogram (CT scan), PET scan. Detailed imaging of the colon and surrounding structures, to detect spread of the disease and planning for surgery.
Tumour markers: Sr. CEA and CA 19-9 levels, though not diagnostic in itself, but can be used for monitoring.
WHAT ARE THE STAGES OF RECTAL CANCER?
There are four stages
Stage I: When cancer is within the lining of the rectum
Stage II: When cancer has involved the entire thickness of colon and few lymph nodes
Stage III: When cancer has involved adjacent organs and considerable lymph nodes
Stage IV: When cancer has spread to distant organs (mostly liver and lungs)
WHAT ARE THE TREATMENT OPTIONS FOR RECTAL CANCER?
Treatment depends on various factors, most important being stage of the cancer, location and general health of the patient. Rectal cancer treatment differ from that of colonic cancer. As the rectum is situated in narrow pelvic cavity, in close proximity with surrounding organs and also difficulty in visualization during surgery; previously local recurrence after surgery was major issue. In current times, this issue has been overcome by incorporation of neoadjuvant chemoradiation (NACTRT) before surgery. NACTRT and concept total mesorectal excision (TME) has revolutionized the rectal cancer treatment.
Early tumours can be treated by endoscopic techniques like polypectomy and endoscopic resection. These therapies avoid a major surgery and removal of the colon. But they require strict follow up and repeated endoscopies to see that disease does not recur.
Surgery: This means removal of a part or entire rectum and subsequently maintaining the continuity by joining to the anus or by bringing out the opening of the intestine on the abdominal wall (stoma). This also involves removing the lymph nodes. This can be done as an open surgery or minimally invasive techniques (laparoscopic or robotic surgery). After this surgery additional treatments may be required in form of chemotherapy or radiation depending on the pathology report. Surgery can also be used for staging the disease (staging laparoscopy).
Radiation: this is very important aspect of rectal cancer treatment. Radiation is given to kill the tumour cells, usually before the surgery or as part of combination therapy.
Chemotherapy: Injectable drugs are given either before or after surgery, or as a part of combination therapy
After any modality of treatment, a strict follow up with your oncologist is important to pick up complications or recurrence of disease as early as possible.
Rectum is pouch like portion of the large intestine. It acts like a reservoir for holding stools until the urge to defecate. It is about 5 inches long and is followed by anus. It has four linings.