Histology & Colorectal Cancer

Malignant growth in the colon or rectum is referred to as colorectal cancer or colon cancer. Several factors such as age, diet, family history and chronic infections of the colon can cause colon cancer. Colon cancer is initially diagnosed by doctors during routine rectal examination and colonoscopy. To diagnose the cancer in detail, doctors will perform tumor histology (the microscopic study of a tissue section); this will categorize and describe the cancer in detail and determine its responsiveness to specific treatments.

Types of Colon Cancer

• Tumor histology will categorize the cancer into a particular type. It can be either adenocarcinoma (95 percent of all colon cancers), epidermoid carcinomas (0.52 to 0.29 percent) or other rarer types of cancer. The overall incidence of adenocarcinoma increases with age until after age 59, whereas epidermoid carcinoma, which is rare, occurs in individuals age 30 to 49.

Tumor Grade

• Histological examination of the tumor also determines the grade level of the cancer. For example, signet-ring cell carcinoma, small cell carcinoma and undifferentiated carcinoma are assigned a high tumor grade. Well-differentiated tumors are graded higher than moderately and low-differentiated tumors. Tumor grade is an important factor that will determine the prognosis of the cancer.

Histology and Treatment

• Tumor histology helps to determine the type of treatment the patient will be receiving. Population studies conducted on patients with different histology results predict for different kind of treatment. For example, according to the Annals of Oncology, patients with advanced mucinous histology (the most common pattern in adenomatous carcinomas) had a poorer response to a commonly used chemotherapeutic drug for colon cancer and reduced survival rates compared with patients with nonmucinous colorectal cancer.