What is Colorectal Cancer?Colorectal cancer (CRC) is cancer that starts in the colon or rectum. Most colorectal cancers start as a growth on the inner lining of the colon or rectum, called a polyp. If cancer forms in a polyp, it can grow into the wall of the colon or rectum over time. About 96% of colorectal cancers are adenocarcinomas, which affect the cells that make mucus to lubricate the inside of the colon and rectum (American Cancer Society, 2018).
Risk FactorsMany lifestyle-related factors have been linked to colorectal cancer, such as being overweight or obese, physical inactivity, certain types of diets (low-fiber, high-fat), smoking, and alcohol use. Other risk factors include age (over 45), personal history of colorectal polyps/cancer, personal history of inflammatory intestinal conditions, family history of colorectal cancer/adenomatous polyps, inherited genes/syndromes, racial and ethnic backgrounds, and type 2 diabetes. (American Cancer Society, 2018)
According to the National Cancer Institute, colorectal cancer will account for approximately 8.3% of all new cancer cases in the United State in 2020. It is expected that 2,650 new colorectal cancer cases will come from Massachusetts alone.
Should I get screened?
Screening can detect precancerous growths that can be removed, or detect cancer at an early stage when treatment is less extensive and more successful. The ACS recommends that people of average risk of colorectal cancer start regular screening at age 45. Average risk means you do not have a personal or family history of colorectal cancer or certain types of polyps, a personal history of inflammatory intestinal conditions, a confirmed or suspected hereditary colorectal cancer syndrome, or a personal history of radiation exposure to the abdomen or pelvic area. Average-risk individuals who are in good health with a life expectancy of more than 10 years should continue regular screening through the age of 75. If you are between ages 76 and 85, talk with your doctor about your preference, overall health, and prior screening history. Screening is not recommended after the age of 85.
What are my screening options?
There are two types of screenings: stool-based tests and visual (structural) exams. Stool-based tests are less invasive, but must be done more often, and are typically not recommended for high-risk individuals. Visual exams look at the structure of the colon and rectum for abnormal areas. This can be done with a scope inserted into the rectum, or special X-ray tests.
Colorectal cancer may not cause symptoms right away. Some signs to look for include:
- Change in bowel habits lasting more than a few days (diarrhea, constipation, narrowing of the stool)
- No feeling of bowel relief with bowel movement
- Rectal bleeding (bright red blood) or blood in the stool
- Anemia (low red blood cell counts)
- Persistent abdominal discomfort such as cramps, gas, or pain
- Weakness and fatigue
- Unintended weight loss
While these symptoms could be caused by other conditions, it is important to see your doctor right away so the cause can be found and appropriately treated.
The stage of the cancer determines how far it has spread, which can lead to knowing how serious it is and how it is best treated. Staging uses the TNM system, which depends on tumor size (T), the spread to nearby lymph nodes (N), and the spread to distant sites (M).
Also known as carcinoma in situ, or intramucosal carcinoma, the cancer has not grown beyond the inner layer (mucosa) of the colon or rectum.
The cancer has grown through the muscularis mucosa into the submucosa (T1) or muscularis propria (T2). It has not spread to nearby lymph nodes or distant sites (N0, M0).
Once a biopsy reveals cancer cells and a PET scan confirms a tumor, your physician may prescribe radiation therapy. Radiation therapy may be used as your primary treatment or in conjunction with surgery or chemotherapy. At Alliance Radiation Oncology, we offer external beam radiation therapy (EBRT). EBRT is used to treat colorectal cancer non-invasively by delivering thousands of precise, high-energy radiation “beamlets” to the cancer cells. It is a safe and effective treatment for colorectal cancer, damaging cancer cells and making them unable to multiply, while minimizing damage to surrounding healthy tissue. Side effects are usually minimal, with most patients returning to normal daily activities after each treatment. Several factors determine candidacy for radiation therapy treatment including the stage of the cancer, potential side effects, age, and overall health.