MANILA, Philippines - The Bayer HealthCare Pharmaceuticals recently shared the prevalence, incidence and risks of Colorectal Cancer worldwide. Colorectal cancer (CRC) occurs when malignant (cancer) cells form in the tissues of the bowel (colon or rectum). The majority of cancers occurring in the colon or rectum are adenocarcinomas, cancers that originate in glandular tissue, and account for 95 percent of all large bowel tumors.
For most people, CRC begins as a polyp on the inner lining of the colon or rectum and grows into a tumor over the period of several years. Metastatic colorectal cancer (mCRC) occurs when the cancer has spread to another part of the body.
Prevalence and Incidence
CRC is one of the most prevalent cancer types worldwide, with an estimated 1.36 million people diagnosed in 2012. The mortality rate of CRC is approximately half of its global incidence. A total of 694,000 people died from CRC in 2012, making it the fourth most common cause of cancer death in the world. The incidence is noticeably higher in men than in women (ratio 1.4), however there is up to a ten-fold difference in incidence in different parts of the world.
The variation in incidence of CRC across the world can be partially attributed to diet, specifically the consumption of red and processed meat, low fibre, and alcohol. In 2008, almost 60 percent of cases were diagnosed in the developed world. As diets worldwide become more westernized, the incidence is increasing in countries where rates were previously low. Also, people of Ashkenazi Jewish heritage have one of the highest risks of CRC and, in the United States, African Americans have the highest incidence and mortality rate associated with CRC.
The five-year survival rate of people diagnosed with stage 1 colorectal cancer, where the tumor is confined to the organ in which it started, is 74 percent. However, by stage IV, when the cancer has spread to distant sites, the five-year survival rate decreases to only six percent.
Symptoms
Most colorectal cancers do not cause any symptoms in the early stages, so they can grow 'silently' for years while the patient feels perfectly healthy. When clinical symptoms occur, the tumor is often at an advanced stage.
Some patients notice changes in their pattern of bowel movements (unexplained diarrhea or constipation). Patients may also have pain, and if the cancer is situated near the anus there may be red blood when moving the bowels. As a person loses blood over time, they will develop anemia, or lowered red blood cell count, causing them to feel tired and weak. Unexplained weight loss is another sign that a cancer may be present, but this is by no means exclusive to CRC.
Biomarker for Colorectal Cancer
KRAS, or the kirsten ras oncogene, has been implicated in various cancers including lung, pancreatic and colorectal cancers. An estimated 40 percent of colorectal tumors carry KRAS mutations and commercial screening tests are available to test for mutations.1 Research has shown that patients with KRAS mutations may not respond as well to certain therapies over others, and has played an important role in treatment selection for these patients.
Treatment Options
Treatment options depend on the stage of the cancer.
Many people with early CRC can have surgery to remove the cancer. Following surgery, some doctors will give radiotherapy and/or chemotherapy to prevent the cancer from coming back. Doctors will also give chemotherapy to kill any remaining cancer cells left behind after the operation.
Once colorectal cancer has metastasized to another part of the body, the chances of being cured dramatically decline.
Chemotherapy, radiotherapy and surgery are all options for metastatic colorectal cancer (mCRC).
However, chemotherapy is often supplemented with the use of biologic therapies.
Biologic therapies are drugs that help the body control the growth of cancer cells. They are targeted therapies that use drugs or antibodies to identify and attack specific cancer cells without harming normal cells.
Bayer's Regorafenib (Stivarga) tablets is an example of a biologic therapy for the treatment of adult patients with mCRC whose disease had progressed after failure with standard therapies.
It is now available in the Philippines following its approval for mCRC in several countries worldwide, including the US and Japan.