By – Dr Tejinder Kataria, Chairperson, Radiation Oncology & Cancer Center, Medanta – The Medicity
The incidence of Colorectal cancers in India is less than that of the Western world. It is the seventh most common cancer in India as per Globacon-2018 data and an estimated 27,600 cases is the incidence of new cases with an annual 19,500 succumbing to colorectal cancer. The 5-year prevalence of persons living with colorectal cancer is 53,700 for all ages.
The incidence is lower in India due to the lesser consumption of red meat as compared to the Western world and a higher intake of vegetarian foods.
Symptoms of colorectal cancer
Symptoms of colorectal cancer are-red coloured stools due to painless bleeding, the passage of black-tarry stools, anaemia, nausea, vomiting, loss of weight, loss of appetite, tiredness and loss of interest in work/surroundings, pain abdomen, bloating and gaseous distension, loss of interest or lack of appetite, a feeling of incomplete evacuation, alternating diarrhoea and constipation, persistent constipation and narrow stools, pain while passing stools.
Diagnosis and treatment
The diagnosis of colorectal cancers is made by doing serum tumour marker-CEA, lower GI endoscopy or ultrasonogram endoscopy and biopsy. Additional imaging with a CT scan or MRI can assist in the staging of the loco-regional disease. Patients with pre-disposition to familial cancers include colorectal cancers in multiple family members. Pre-cancerous polyps can be detected on endoscopy and removed to prevent frank cancer development in such cases-this is known as surveillance endoscopy. If a first-degree relative had colon cancer then the family members should start surveillance endoscopy at 50 years of age.
The treatment for colon cancer is surgery first
The treatment for colon cancer is surgery first followed by chemotherapy and or radiation. For rectal cancers up-front radiation and chemotherapy and given to down-stage the low-lying cancers (within 5-8 cms from the anal verge) to prevent permanent colostomy. A total neo-adjuvant treatment has recently been found to preserve the sphincter in advanced rectal cancers.
MMRd-Gene- Mismatch repair deficient or Micro-satellite -instability(MSI) cancer cells in colorectal cancers carry many DNA mutations and are common in Lynch Hereditary syndrome. It occurs in approximately 15 per cent of colorectal cancers and such cancers do not respond well to conventional chemotherapy. A personalized medicine approach with immunotherapy and targeted drugs is recommended in such patients.