Chapter 078. Prevention and Early Detection of Cancer (Part 1)

Harrisons Internal Medicine Chapter 78. Prevention and Early Detection of CancerPrevention and Early Detection of Cancer: Introduction Improved understanding of carcinogenesis has allowed cancer prevention and early detection (also known as cancer control) to expand beyond the identification and avoidance of carcinogens. Specific interventions to prevent cancer in those at risk, and more sensitive and specific screening for early detection of cancer are the goals.Carcinogenesis is not simply an event but a process, a continuum of discrete cellular changes over time resulting in more autonomous cellularprocesses. Prevention concerns the identification and manipulation of the genetic, biologic, and environmental...
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Chapter 078. Prevention and Early Detection of Cancer (Part 1) Chapter 078. Prevention and Early Detection of Cancer (Part 1) Harrisons Internal Medicine > Chapter 78. Prevention and EarlyDetection of Cancer Prevention and Early Detection of Cancer: Introduction Improved understanding of carcinogenesis has allowed cancer preventionand early detection (also known as cancer control) to expand beyond theidentification and avoidance of carcinogens. Specific interventions to preventcancer in those at risk, and more sensitive and specific screening for earlydetection of cancer are the goals. Carcinogenesis is not simply an event but a process, a continuum ofdiscrete cellular changes over time resulting in more autonomous cellularprocesses. Prevention concerns the identification and manipulation of the genetic,biologic, and environmental factors in the causal pathway of cancer. Education and Healthful Habits Public education on the avoidance of identified risk factors for cancer andencouraging healthy habits contributes to cancer prevention and control. Thephysician is a powerful messenger in this education campaign. The patient-physician encounter provides an opportunity to teach patients about the hazards ofsmoking, the features of a healthy lifestyle (including diet and exercise), use ofproven cancer screening methods, and sun avoidance. Smoking Cessation Tobacco smoking is the most modifiable risk factor for cardiovasculardisease, pulmonary disease, and cancer. Smokers have a 33% lifetime risk ofdying prematurely from a tobacco-related cancer, cardiovascular, or pulmonarydisease. Tobacco use causes more deaths from cardiovascular disease than fromcancer. Lung cancer and cancers of the larynx, oropharynx, esophagus, kidney,bladder, pancreas, and stomach are all tobacco-related. The degree of smoke exposure, meaning the number of cigarettes smokedper day as well as the level of inhalation of cigarette smoke, is correlated with riskof lung cancer mortality. Light- and low-tar cigarettes are not safer becausesmokers tend to inhale them more frequently and deeply. Those who stop smoking have a 30–50% lower 10-year lung cancermortality rate compared to those who continue smoking, despite the fact that somecarcinogen-induced gene mutations persist for years after smoking cessation.Smoking cessation and avoidance have the potential to save more lives than anyother public health activity. The risk of tobacco smoke is not limited to the smoker. Environmentaltobacco smoke, known as second hand or passive smoke, causes lung cancer andother cardiopulmonary diseases in nonsmokers. Tobacco prevention is a pediatric issue. Over 80% of adult Americansmokers began smoking before the age of 18. Nearly 20% of Americans aged 12–18 have smoked a cigarette in the past month. Counseling of adolescents andyoung adults is critical to prevent smoking. A physicians simple advice to not startsmoking or to quit smoking can be of benefit. Physicians should query patients ontobacco use on every office visit, record the answer with the vital signs, and asksmokers if they would like assistance in quitting. Current approaches to smoking cessation recognize that smoking is anaddiction (Chap. 390). The smoker who is quitting goes through a process withidentifiable stages that include contemplation of quitting, an action phase in whichthe smoker quits, and a maintenance phase. Smokers who quit completely aremore likely to be successful than those who gradually reduce the number ofcigarettes smoked or change to lower tar or nicotine cigarettes. More than 90% ofthe Americans who have successfully quit smoking did so on their own withoutparticipation in an organized cessation program, but cessation programs arehelpful for some smokers. The Community Intervention Trial for SmokingCessation (COMMIT) was a 4-year program; it demonstrated that light smokers(25 cigarettes per day). Heavy smokers may need an intensivebroad-based cessation program that includes counseling, behavioral strategies, andpharmacologic adjuncts, such as nicotine replacement (gum, patches, sprays,lozenges, and inhalers) and bupropion. Cigar smoking has increased in the past decade. The health risks of cigarsare similar to those of cigarettes. Smoking one or two cigars daily doubles the riskfor oral and esophageal cancers; three or four cigars daily increases the risk of oralcancers more than eightfold and esophageal cancer fourfold. The risks ofoccasional use are unknown. Smokeless tobacco is the fastest growing part of the tobacco industry andrepresents a substantial health risk. Chewing tobacco is a carcinogen linked todental caries, g ...