Overview of Gastrointestinal Cancers

Cancers of the gastrointestinal (GI) tract include those of the esophagus, stomach, colon, rectum, and anus. Risk factors, incidence, prevalence, and prognosis vary for each site. Many of the risk factors are modifiable, and in a significant number of cases, the cancers are preventable with proper screening and curable when detected and treated at an early stage. Esophageal cancer is a treatable but rarely curable cancer. Incidence has increased over the past 20 years in the United States, particularly adenocarcinomas of the esophagus, which have increased by 450% in Caucasian men and 50% in African American men (Enzinger & Mayer, 2003). Squamous cell carcinomas are more common in the rest of the world. Treatment involves surgical resection, whenever possible, followed by chemotherapy and radiotherapy. Men and African Americans have a higher incidence of esophageal cancer than do other groups (Posner, Forastiere, & Minsky, 2005). Gastric cancer ranks second in cancer deaths across the world. In the United States, incidence has been decreasing dramatically and currently occupies 14th place among cancer incidences (American Cancer Society [ACS], 2006). Adenocarcinomas represent 90%–95% of all gastric malignancies. Over the past 25 years, the number of gastric cancers occuring at the gastroesophageal (GE) junction and in the cardia has dramatically increased. Treatment for gastric cancer is surgery, followed by chemotherapy and radiotherapy (Pisters, Kelsen, Powell, & Tepper, 2005). Colorectal cancer (CRC), a preventable, highly treatable, and often curable cancer, is common in men and women. Surgery is the primary form of treatment and results in cure in more than 50% of the patients. Local or distant recurrences develop in many patients after surgical resection, and those with the highest risk of recurrence receive chemotherapy. More than half of the patients are diagnosed at stage III or with metastatic disease, and minorities are diagnosed more often at advanced stages of cancer than Caucasians (Xiong & Ajani, 2004). For the four major cancer sites (prostate, female breast, lung, and CRC), minority populations have a greater risk of cancer death than other groups (Clegg, Li, Hankey, Chu, & Edwards, 2002). Anal cancers are uncommon, representing 4% of all cancers (Ryan, Compton, & Mayer, 2000). In the United States, squamous cell carcinomas are the most common histology. The risk of developing anal cancers is rising, with people engaging in receptive anal intercourse and with those having a higher number of lifetime sexual partners being at higher risk (Cummings, Ajani, & Swallow, 2005). A strong correlation exists between human papillomavirus (HPV) infection and anal cancer. Treatment consists of surgery, radiation, and chemotherapy (Cummings et al.).