About Rectal Cancer
Rectal cancer affects a part of the digestive system called the rectum. The rectum is the lowest part of the large intestine, connecting the colon to the anus. The part of the rectum closest to the colon is called the upper rectum, while the part of the rectum closest to the anus is called the lower rectum.
Early symptoms of rectal cancer might include blood in the stool; persistent problems in defecating (long-lasting diarrhea or constipation); feelings of cramping, distension or pain in the area of the bowel or anus; or a persistent decrease in the size of the stool.
At Johns Hopkins, our specialists treat rectal cancer patients at every stage of disease. Our team of specialists includes medical oncologists, surgeons and radiation oncologists working together to develop the best treatment plan for each patient.
Rectal Cancer: What You Need to Know
- Screening for rectal cancers can include a colonoscopy (which examines the entire length of the colon) or a flexible sigmoidoscopy (which examines all of the rectum and part of the colon). The fecal occult blood test, which looks for signs of bleeding in the stool, may also be used to screen for cancer.
- About 20 percent of rectal cancers have some hereditary link. Rectal cancer screening experts at the Johns Hopkins Kimmel Cancer Center offer genetic testing for these common genetic variations.
- In general, early stage rectal cancers (stage 1 and 2) are confined to the rectum and have not moved outside its muscular wall. Stage 3 rectal cancer has spread to organs and tissues or lymph nodes directly outside the rectal wall. Stage 4 rectal cancer has spread to distant lymph nodes and organs, such as the lung or liver.
- Before treatment, Johns Hopkins team members may recommend further imaging of rectal cancer through MRI or ultrasound that focuses on the rectum and surrounding tissues.
- Rectal cancer treatments may weaken or damage the muscles used to go to the bathroom, as well as the reproductive organs. The rectal cancer multidisciplinary clinic offers personalized advice on pelvic floor therapy, nutrition and fertility preservation, as well as a rectal cancer survivorship and mentorship program.
Genetic Testing for Rectal Cancer
There are some genetic mutations that have been linked to inherited forms of colorectal cancer, and other mutations that can help guide a patient’s treatment when they are identified. Johns Hopkins medical oncologists recommend genetic testing for rectal cancer patients if the patients have a close relative with colorectal cancer or a family history of colorectal cancer, or if the cancer is metastatic.
Some of the genetic tests for rectal cancer risk and treatment guidance include:
- Hereditary colon cancer conditions: hereditary colon cancers are passed on through families and have a known genetic cause. Johns Hopkins has a dedicated webpage about these conditions, including familial adenomatous polyposis (FAP). Lynch syndrome, and APC I1307K, an inherited gene mutation discovered by Johns Hopkins scientists in 1997.
- RAS, BRAF mutations: patients with certain mutations in the KRAS, NRAS and BRAF genes, which are involved in how colorectal cells divide and grow, may not respond as well to chemotherapy drugs such as cetuximab and panitumumab. These genes are usually tested in stage IV rectal cancer patients.
- Microsatellite instability: microsatellite instability refers to mutations in the genes that help to regulate DNA function, sometimes called “spell-checker genes.” Mutations in these genes can cause areas of the DNA to become unstable. A high frequency of instability is called microsatellite instability-high (MSI-H), and can be a marker of certain types of colorectal cancer like Lynch syndrome. A MSI-H diagnosis might also be used to guide therapy, since these tumors may respond better to immunotherapy treatments such as pembrolizumab instead of more traditional chemotherapies.
The Johns Hopkins Colon Cancer Risk Assessment Clinic provides genetic testing for patients with a family history of colon cancer. Genetic testing of rectal cancer patients may also be recommended to patients who visit the Johns Hopkins Rectal Cancer Multidisciplinary Clinic.