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Colorectal cancer is defined as a cancer that affects the bowel or large intestine – the colon and rectum. It is considered to be the third most deadly form of cancer affecting both women and men globally, according to the National Library of Medicine (2019). In India, colorectal cancer is the seventh leading cause of deaths.
Colorectal cancer symptoms are often not visible immediately. Albeit, a few symptoms that may occur and are indicative of the disease include bowel movement changes such as prolonged constipation, diarrhoea, or thin stool, need for multiple bowel movements, presence of blood in brown/black stool or bright red blood implying rectal bleeding, abdominal discomfort or contractions, fatigue/lethargy, and unexplained weight loss. Colorectal cancer symptoms may resemble other digestive issues. Thus, early screenings and diagnosis are pivotal in distinguishing and eliminating the possibility of cancerous cells.
Additionally, as colorectal cancer patients experience severe blood loss in the digestive tract for an extensive period, anaemia or reduced red blood cell count in blood tests can represent an early symptom of the condition. As the cancer aggravates through different stages, the spread of primary colon cancer cells to other organs termed as metastases results in visible impact – large liver, breathing complications due to metastatic lung cancer, or jaundice.
There are numerous causes of developing colorectal cancer, including genetic predisposition, race, age, fast food diet rich in fats such as burgers and pizzas, ulcerative colitis, Crohn’s disease to name a few. Specifically, apart from genetics, unhealthy lifestyle choices such as poor nutrition, lack of physical activity and lifestyle disorders (diabetes, obesity) are deemed as a major risk factors for the development of colorectal cancer.
Colorectal cancer symptoms are often difficult to identify initially as aforementioned, thereby, early detection becomes challenging. Upon detection, further tests are required to examine and accordingly categorise the initial spread of cancerous cells from the large intestine to adjacent body parts.
The stage is determined through certain tests to then ascertain the required and appropriate treatment. The initial test done is a colonoscopy with a biopsy which proves the diagnosis. Further a CT scan or a PET Scan is done to siege the disease. In rectal cancers an MRI or a transrectal ultrasound may also be done. A CEA (corcinoembryonic antigen) is a tumor marker specific to colorectal cancer & is done via a blood test.
The treatment for colorectal cancers is a multimodality approach involving a combination of surgery, chemotherapy, radiotherapy & immunotherapy. The surgery is most often performed by the minimally invasive laparoscopic technique which not only allows good oncologic outcomes but also fastens patient’s recovery, other surgery and provides better cosmesis. The prognosis after treatment is relatively good. After treatment patients are kept under surveillance to detect any tumor recurrence.
Preventive measures can be taken to minimise risks and early diagnosis of colorectal cancer given the delay in identifiable symptoms. Timely and regular screenings are recommended especially to individuals with relevant family history or above the age of 45, crucial lifestyle changes including weight/diet management, avoiding alcohol.