Colorectal Cancer: Prevention, Early Diagnosis And Current Treatment
Colorectal cancer, or cancer affecting the large intestine, is a common cancer seen in India. Although more common at higher age, it can occur even in very young and middle-aged patients.
How can we prevent colorectal cancer?
Maintaining a healthy lifestyle incorporating a balanced diet and an exercise schedule, can help avoid obesity which is a known risk factor for colorectal cancer. Avoiding smoking, excessive alcohol intake, reducing red meats in diet and screening of population at increased risk of colorectal cancer with colonoscopy can help prevent colorectal cancer. People with family history of colorectal cancer, and those with inflammatory bowel disease, more so ulcerative colitis are at a significantly higher risk of colorectal cancer. Colorectal cancers arise from small polyps, most of which diagnosed timely can be removed at colonoscopy, thereby reducing the risk of subsequent development of cancer.
Symptoms of colorectal cancer
Patients with colorectal cancer at different sites have a slightly different symptoms, although a common thread is some blood loss occurring from the cancer. Patients may have obvious blood in stools, or more often observe weakness, lethargy or even at times cardiac symptoms due to a slow ongoing small amount bleeding which is not noticed by the patient. Besides the bleeding, patients with tumours in right colon usually have abdominal pain, left sided tumours with worsening constipation whereas rectal tumours present with a feeling of incomplete evacuation and occasionally as a mass coming out of anus. Some patients present in emergency with complete intestinal obstruction resulting from encroachment of the intestinal lumen by the cancer
Early diagnosis: How and why?
As already stated, most colorectal cancers arise from small polyps. Colonoscopy (done by passing a scope through the anus) helps visualize the lesions and in selected cases be treated with a simple colonoscopic resection which is very simple, usually safe and enough treatment for polyps and some very early stage cancers. Unfortunately, more often, tumours in India present at a later stage, thereby not just needing further tests (CT scan, MRI, PET-CT) but also need treatment with some combination of surgery, chemotherapy and radiotherapy. Tumours diagnosed early, are easier to treat, require less treatment (thereby reducing cost) and have better long-term outcomes.
What is the role of surgery in treatment for colorectal cancer and what does it entail?
Surgery is the mainstay of treatment. In colon cancer, most often it is the first modality of treatment unless the disease has spread to other parts of body in which case chemotherapy is given first. Early rectal cancers are treated with surgery, more advanced ones with some combination of chemotherapy and radiotherapy prior to surgery. Surgery entails removal of the tumour along with a segment of normal large intestine with regional lymph nodes (removing adequate number of lymph nodes) and mostly joining the two healthy ends of the intestine to each other for restoration of continuity of digestive tract.
Why minimally invasive (laparoscopic or robotic) surgery for colorectal cancer?
Similar to surgery for gall bladder stones which was earlier done by open surgery and now almost always with laparoscopic (or minimal access) surgery, most abdominal cancers can now be managed with laparoscopic or even better with robotic techniques. There are enough published studies which have established safety and good oncologic outcomes with laparoscopic and robotic surgery for surgical management of cancers of esophagus (food pipe), stomach, colorectal cancers and gradually for even pancreatic and liver cancers. There are a number of advantages with use of minimally invasive techniques, namely a magnified view at surgery, smaller incisions and therefore lesser postoperative pain, shorter hospital stay, and earlier return to normal activity and start of further treatment when needed. Robotic surgery, in addition, improves significantly the ease of performing the operation with better visualization, and use of robotic arms guided by the surgeon.
Is it possible to preserve normal passage for stools at surgery in rectal cancer?
Patients with cancers affecting the rectum (distal most part of large intestine), even those with tumours as distal as 2-3 cm from anal verge can be considered for preservation of normal passage of stools. Diagnosing tumours early, use of chemoradiotherapy prior to surgery as needed, and use of newer technologies of laparoscopy and now robotic surgery helps achieve this goal. Sound surgical knowledge, use of stapling devices and techniques like ultralow anterior resection and intersphincteric resection (for selected patients with very low tumours) play an important role in ensuring good outcomes.
How is management of stage IV colorectal cancer changing?
Stage IV cancer arising from any site in the abdomen is usually associated with poor outcome. However, colorectal cancer is an exception. Selected patients with stage IV cancer (limited spread to lung, liver or even peritoneal cavity) can now be cured of their disease with a combined use of newer chemotherapeutic agents, targeted therapy, surgery, interventional radiologic techniques and radiotherapy with good long-term survival. Long term disease control can be achieved in nearly 30-40% patients with isolated liver or lung metastatsis. Patients with disease spread in peritoneal cavity can also be treated with systemic chemotherapy followed by cytoreductive surgery and HIPEC, a technique in which heated chemotherapy medicines are circulated in abdomen of patient at surgery. Even if the disease is deemed incurable, treatment with chemotherapy and targeted agents helps most patients survive more than 2 years with a significant proportion of them surviving more.
