Colon Cancer: Symptoms, Clinical Features and Treatment

Colon Cancer is very common type of cancer and the most cases of large bowel cancers are influenced by environmental factors. The incidence of disease is most common among people living in the upper socioeconomic conditions or urban areas. There are many types of colorectal cancer which are related to familial inheritance but most are the cause of diet intake like red meat ingestion. Obesity and Insulin resistance are found to be another causes of colorectal cancer. There is an association of Strep Bovis found with the patients of colorectal cancer.

Colon Cancer Symptoms/Clinical Features

• The most common symptom seen in colorectal patients is abdominal pain, constipation due to obstruction and anemia due to chronic bleeding mainly.
• Other symptoms like weight loss, fever and fatigue are very common.
• Hematochezia, tenesmus and a sensation of a mass in the rectum can be seen in case rectum is involved.
• In the colon cancers where multiple organs are involved like Turcot syndrome, the other organ manifestations like seizure will also be seen.

Also Read: Trisomy 13 (Patau Syndrome): Causes, Symptoms, Types, Diagnosis, Treatment And Prevention

Colon Cancer Risk Factors

• Lifestyle
  • Regular consumption of Red meat
  • Tobacco
  • Alcohol use

• Family history
  • Inherited colon cancer syndrome like Lynch syndrome( HNPCC), familial adenomatous polyposis.
  • Family history of adenomatous polyps or colon cancer.

• Medical History
  • Diabetes Mellitus type2
  • Obesity
  • Any radiational exposure to the abdomen

Also Read: Soto’s Syndrome: Causes, Symptoms, Diagnosis, Treatment, Prevention and Complications

Colon Polyp Types

It can be neoplastic or non-neoplastic

Non-neoplastic

1. Hyperplastic Polyps- It mainly occurs in Rectosigmoid region. If serrations are present along the full thickness then it can lead to cancer. 

2. Hamartomatous Polyps

• Juvenile Rectal Polyp- The clinical feature of this polyp is Bleeding per rectum. These are commonly seen in Rectum. SMAD2, SMAD4 are different types of mutations seen.
• Peutz Jeghers Syndrome- It is an autosomal dominant disorder in which there is a mutation of Tumor suppressor gene that causes unregulated tissue growth. The features are pigmented macules on lips and buccal mucosa along with presence of >2 gastrointestinal hamartomatous polyps. Polyp is arborishing polyp ( a tree like structure with branches).
• Cowden syndrome-  It is caused by PTEN gene mutation in chromosome 10. There is a nemonic for its features - PTEN.
  • P - Polyps and Breast cancer
  • T - Thyroid cancer and thickening of skin
  • EN - Endometrial cancer.

• Tuberous Sclerosis- Due to mutation in two genes: TSC1 gene ( Hamartin protein) and TSC2 ( Tuberin protein). Presence of hamartomatous polyps in the intestine.
• Inflammatory polyps - These develops in the patients have inflammatory bowel disorder like Ulcerative Colitis.

Neoplastic polyps

• Sessile Serrated adenomas
• Tubular adenoma ( Round structure)
• Tubulovillous adenoma ( Combination of both villous and rounded tubules)
• Villous adenoma- It has maximun risk of cancer.

Familal Syndromes

Familial Adenomatous Polyposis ( FAP)

• There is mutation in APC gene and there are more than 1000s of polyps present.
• There is 100 percent risk of cancer.
• Usually develops under the age of 30 years old.
• There are 3 types of FAP -
  • Classical FAP- More than 100 polyps found and there is congenital hypertrophy of Retinal pigment epithelium.
  • Turcot FAP - Its classical presentation is presence of CNS tumor( Medulloblastoma and Glioblastoma) along with colon polyps.
  • Gardner FAP- The manifestations other than Colon polyp found in this syndrome are Epidermal cysts , Osteoma and Supernumerary teeth ( extrateeth will be present).

Lynch Syndrome ( HNPCC)

• Defect in DNA mismatch repair ( MLH1 and MSH2) genes.
• There is other organ cancers invloved in this syndrome, these are- Colorectal cancer , endometrial cancer and ovarian cancer. Therefore when patient is diagnosed with colon cancer due to HNPCC other organs should be screened as well.

Also Read: Williams Syndrome: Causes, Symptoms, Diagnosis, Treatment and Prevention

Colon Cancer Screening  and Diagnosis

• Patient presented  with suscpicion of Colorectal cancer should be counselled properly and the diagnosis should be confirmed using colonoscopy.
• Regular screening  should be done in case of FAP, begin at the age of 10-12 years. Colonoscopy with biopsy is the most important screening method.
• Routine colonoscopy should be done in every individual at the age of 45-50 years.
• Other screening methods are Sigmoidoscopy, FOBT etc.

Also Read: Calciphylaxis: Causes, Symptoms, Risk Factors, Diagnosis, Treatment and Complications

Colon cancer treatment

• Patients diagnosed with colorectal cancer should be counselled properly and staging should be done by involving oncologists and gastro-surgeons into the case.
• If possible patients with adenocarcinoma of the colon should be offered surgical resection with cure.
• If there is metastatic spread to the liver then resection of the hepatic mass and the colon tumor should be done.
• If the tumour is extensively metastatic and non-resectable then chemotherapy plays an important role.
• Proper surveillance after colon cancer resection should be done. 

Also Read: Thalassemia - Symptoms and Causes

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