Several Risk Factors Associated with Rectal Cancer
There is no one specific cause; however, rectal cancer has often developed in individuals with the following common risk factors:
- Cigarette smoking
- Alcohol usage
- Positive familial history
- Poor diet
- Absence of physical activity
- Lack of rectal and colon cancer screenings
- Gastrointestinal disease
- Age [1,2]
Rectal Cancer Signs and Symptoms
Signs and symptoms of rectal cancer often mimic those related to other gastrointestinal disorders such as inflammatory bowel disease or hemorrhoids. Patients with or without the above risk factors, experiencing any of the following signs and symptoms, should err on the side of caution and visit their health care provider immediately.
Common signs of rectal cancer include but are not limited to: change in bowels, diarrhea, constipation, blood in stool, bloating, gas pains, abdominal cramps and fullness, unintentional weight loss, fatigue and vomiting. 
Customary symptoms associated with rectal cancer tend to revolve around:
- Unexplained weight loss
- Obstruction 
Any time a patient finds blood in his or her stool, it should be reported immediately because it is indicative of an internal problem. While there are many known etiologies for blood within stool, only a physician can pinpoint its cause.
Oftentimes, rectal cancer patients endure a blockage within their rectum that prevents them from completely evacuating stool from their bowels. They might also have a sensation to pass a bowel movement, yet are unable to do so. The size of the bowel movement can be affected as well. An obstruction can lead to narrow or extremely thin stools due to the lack of free movement within.
Several Tests and Examinations Are Used to Diagnose Rectal Cancer
Doctors will generally order various tests and examinations on patients exhibiting the above signs and symptoms. The fecal occult blood test (FOBT) is the least invasive. A sample of the patient’s stool is placed on special paper. A chemical is then placed on that paper to determine if there is blood in the stool. 
If there is blood present, there is a chance the individual has rectal cancer. The physician may be inclined to order further testing in the form of an endoscopy or digital rectal examination (DRE) to locate the cancerous tumor.
During a DRE, the doctor inserts his or her finger past the anus to feel for cancer along the rectal wall. The DRE is not foolproof, however. If the tumor is located further out from the anus, the doctor may be unable to detect a tumor. In the event a tumor is felt, the physician will proceed with an endoscopy where an endoscope is inserted into the rectum and colon to locate and further investigate the found cancer.
eMedicine Health website. Rectal Cancer Causes, https://www.emedicinehealth.com/rectal_cancer/page2_em.htm#Rectal%20Cancer%20Causes. Accessed December 17, 2010.
UCSF Medical Center website. Rectal Cancer, https://www.ucsfhealth.org/conditions/rectal_cancer/. Accessed December 16, 2010. [2,3]
eMedicine Health website. Rectal Cancer Symptoms, https://www.emedicinehealth.com/rectal_cancer/page3_em.htm#Rectal%20Cancer%20Symptoms. Accessed December 16, 2010.
eMedicine Health website. Rectal Cancer Exams and Tests, https://www.emedicinehealth.com/rectal_cancer/page5_em.htm#Exams%20and%20Tests. Accessed December 17, 2010.