___________________________________________________________________________ Colorectal Cancer
rate in women ranges from 24.6 per 100,000 in Asians/Pacific Islanders to 43.9 per 100,000 in American Indian/Alaska Natives. The annual age-adjusted mortality rates for men and women are 16.0 and 11.3 per 100,000, respectively [9]. The risk of colorectal cancer increases after 44 years of age and rises sharply by 65 to 74 years of age, with colorectal cancer risk doubling in every succeeding decade. Most cases (90%) of colorectal cancer are diagnosed after 50 years of age; only 6% are diagnosed in persons younger than 55 years of age [1; 10; 11]. Although colorectal cancer remains more common in older individuals, the incidence is increasing among younger adults. Between 2004 and 2013, the number of young-onset (before 50 years of age) cases increased 11.4% [12]. In that same period, the number of cases in adults 50 years of age or older decreased 2.5%. Figures for rectal cancer alone are more difficult to ascertain because epidemiologic studies usually report colon and rectal cancer together as colorectal cancer. However, 2022 projections estimate 44,850 new rectal cancer diagnoses [8]. Approximately 4.2% of Americans will be diagnosed with colorectal cancer at some point in their lifetime. Of those diagnosed, 50% will die from the disease. The overall five- year survival rate is 65.7% [10]. Cancer stage at diagnosis strongly influences duration of survival. With colon and rectum cancer, the five-year survival is approximately 91% in patients diagnosed with localized cancer, 72% with limited regional extension, and 14% with distant metastases [13]. Despite advances in surgical techniques and adjuvant therapy, the modest survival improvements in patients with advanced neoplasm provide the rationale for implementing primary and secondary preventive approaches to reduce morbidity and mortality from colorectal cancer [1; 2; 3]. COLORECTAL CANCER RISK FACTORS For most people, the dominant risk factor for colorectal cancer is increasing age. As noted, risk increases dramatically after 50 years of age. Other nonmodifiable factors, such as family history of colorectal cancer, personal history of colorectal cancer or high-risk adenomas, genetic predisposition, and inflammatory bowel disease, also elevate the risk of colorectal cancer [14]. There are also modifiable factors that increase (or decrease) an individual’s risk of colorectal cancer, including alcohol use, cigarette smoking, diet, and physical activity. MODIFIABLE FACTORS Factors Associated with Increased Risk of Colorectal Cancer Excessive Alcohol Use Solid evidence indicates that excessive alcohol use is associated with increased risk of colorectal cancer. Analysis of pooled data found that alcohol consumption greater than 45 g/day
INTRODUCTION Colorectal cancer is the third leading cause of cancer death in the United States, and roughly 35% of those who develop colorectal cancer die from the disease [1; 2; 3]. Improved therapies and widespread primary prevention through screening have resulted in the United States being the only developed country with declining colorectal cancer incidence and mortality [4]. However, there is substantial room for improvement, and primary care provider knowledge of colorectal cancer is essential to continue reducing cases through screening and early detection. While this course addresses important content domains related to colorectal cancer, a few related areas are not addressed: management of cancer-related pain and cancer of the anus. With 90% of anal cancer cases associated with the human papillomavirus (HPV), this malignancy is considered distinct from rectal cancer [5]. In contrast, rectal cancer bears such similarity to colon cancer that both cancers are frequently combined in epidemiologic and clinical reports. EPIDEMIOLOGY Worldwide, colorectal cancer is the second most common cancer in women and the third most common in men [6]. The incidence varies geographically as much as 10-fold, with the highest estimated rates per 100,000 population in Southern Europe (25.3 in men, 16.5 in women) and lowest in Middle Africa (2.9 in men, 2.3 in women). The highest estimated mortality rates per 100,000 population are in Australia/New Zealand (21.3 in both sexes) and the lowest are in Middle Africa (2.6 in both sexes) [6]. In the United States, colorectal cancer is the third leading cause of cancer death, with 106,180 new diagnoses of colon cancer, 44,850 new diagnoses of rectal cancer, and 52,580 deaths projected for 2022 [7]. From 2014 to 2018, colorectal cancer incidence rates declined by 3.7% per year in adults 55 years of age and older, increased by about 2.0% per year in adults 50 to 55 years of age, and increased by 1.5% per year in individuals younger than 50 years of age—a trend that began in the mid-1990s for unknown reasons [8]. The death rate has decreased by 56%, from 29.2 per 100,000 in 1970 to 12.8 in 2019, primarily due to earlier detection. From 2015 to 2019, the death rate declined by about 2% per year [8]. Trends in the United States suggest a disproportionally higher incidence and death from colorectal cancer in Black/African American patients than in White patients. Asian/Pacific Islander individuals have the lowest incidence and mortality from colorectal cancer [9]. The incidence of colorectal cancer is higher in men than in women, with the annual rate in men ranging from 34.4 per 100,000 for Asian/Pacific Islanders to 50.4 per 100,000 for African Americans. The annual incidence
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