In humans, the intestine forms the major part of the digestive tract. It is divided into small and large intestine, based on its appearance. Even though large intestine is considerably shorter in length compared to the small intestine, its represents the major site of intestinal malignancies.
Large intestine consists of the colon and the rectum. The colon which is an inverted U shaped structure located in the periphery of the abdomen is further divided into caecum, ascending colon, transverse colon, descending colon, sigmoid colon, terminating in the rectum. Cancers occurring in any of these sites is termed “Colorectal cancer”.
Here are some FAQs answered!
Some insight into the prevalence of colorectal cancer
Even though the prevalence of colorectal cancer is more in the western world, India has shown an alarming increase in the incidence, to become the third most common cause of cancer related deaths. There are a lot of variations in the presentation of colorectal cancers in India compared to the western world. We see an early age of presentation (mean age- 43 yrs, compared to 50-60 yrs in rest of the world) of significantly advanced cancers (stage 3 -4) with metastasis and worse prognosis. Ignorance, low socioeconomic status, hesitation and delay in seeking medical care for long term symptoms contribute to this. The importance of this comes with the fact that colorectal cancer is one of disorders that have adequate screening tools (colonoscopy and biopsy), capable of detecting cancer in the early stages and when timely utilized, aid in early diagnosis and treatment and thus can prevent a major share of the colorectal cancer deaths.
What are the causes of colorectal cancer?
Colorectal cancers can be due to a family history of inheritable genetic mutations or most commonly sporadic, that has occurred due to environmental or lifestyle changes of the individual. It is observed that adoption of a diet low in vitamins and fiber (fruits and vegetables), and high in fat and refined carbohydrate (maida based and red meat and alcohol) is closely associated with the occurrence of this disease. It is theorized that this reduces the bulk of the stools formed, deterring its easy passage and alters the intestinal bacteria(good bacteria), which in turn increases the synthesis of the toxic chemicals that can remain in contact with the colon for an extended duration of time that can result in carcinogenic changes. Compounding these changes are deficiencies in Vitamins A, C and E that are known antioxidants, neutralizing the free oxygen radicals.
What are the types of colorectal cancer?
Colorectal cancers can clinically be divided into two sets: Right sided (caecum and ascending colon and part of the transverse colon) and Left sided (descending and sigmoid colon along with the rectum). Right sided cancers mainly have fatigue, weakness and undiagnosed anemia as a presentation, whereas left sided cancers have changes in stool passage, bleeding associated with defecation, and pain abdomen. Unfortunately, these are undetected and undiagnosed for very long periods, by which time the cancer would have spread through the layers of the intestine, invaded lymphatics and blood vessels and reached distant organs, leading to metastasis.
How to treat colorectal cancer?
Colorectal cancers in the initial stages are confined to the first two layers of the intestine. Diagnosis at this time almost results in a complete cure of the patient with surgery usually being the only mode of treatment required. Once the tumor spreads across the intestinal layers and reaches the lymph nodes and adjacent organs, treatment involving chemo radiation is needed along with surgery to remove the cancer focus in the body. A thorough body workup to determine the actual stage of the cancer along with the biopsy of the cancerous tissue is essential.