Other Risk Factors for Pancreatic Cancer
Cigarette smoking and family history (ie, at least one first-degree relative affected by the disease) are the predominant risk factors for pancreatic cancer. In addition to smoking, significant avoidable or reversible risk factors include alcohol abuse, obesity, a sedentary lifestyle, a diet high in fats and meats and low in vegetables and folate, and certain environmental exposures (eg, solvents used in dry cleaning, gasoline-related particles, nickel).2,4,8 Risk factors that are unavoidable or irreversible include advancing age, male gender, African-American ethnicity, a non–O blood group type, and a history of radiation treatment.4,8 Analyses of risk factors for pancreatic cancer appear in Table 12,18-20 (inherited risk factors) and Table 22 (noninherited risk factors).
It has been estimated that 20% to 25% of pancreatic tumors are attributable to cigarette smoking, and individuals who smoke carry more cancer-related genetic mutations than do nonsmokers.21,22 Additionally, patients with hereditary pancreatitis who smoke are at double the risk for pancreatic cancer and can develop the disease 20 years earlier than those with the associated genetic mutation who do not smoke.4 Among the germline mutations associated with cancer, BRCA2 mutations have been reported in 12% to 17% of patients with familial pancreatic cancer.23
As of 2010-2011, the US Preventive Services Task Force24 (USPSTF) recommended against routine screening (ie, abdominal palpation for organomegaly, serologic markers, or ultrasonography) for pancreatic cancer in asymptomatic adults; the USPSTF has not yet reviewed the effectiveness of screening patients with hereditary pancreatitis, even though they “may have a higher lifetime risk for developing pancreatic cancer.”24 Screening for pancreatic cancer is usually reserved for patients with a lifetime pancreatic cancer risk of at least 5%; it begins with a genetic analysis to detect mutations associated with pancreatic cancer.4,18 Imaging may follow, with the intent to detect precursor lesions or early pancreatic cancers.4
Clinically silent in its early stages, pancreatic cancer usually presents after the tumor has metastasized to distant organs or has invaded adjacent tissues. Typically, patients with pancreatic cancer have undergone abdominal CT for evaluation of other clinically indicated reasons before receiving this diagnosis.8
The presenting symptoms for pancreatic cancer include, but are not limited to, abdominal pain, midback pain, jaundice, loss of appetite and weight loss, floating stools, dyspepsia, nausea, and depression5,25 (see Figure 125 for a detailed analysis of self-reported symptoms in a study of patients with pancreatic cancer). Both deep and superficial venous thrombosis, which are not unusual on presentation, can be an indication of malignant disease.8,26 In patients with pancreatic cancer, incidence of thromboembolic disease, in its various manifestations, ranges from 17% to 57%.27,28
In a 2010 study, Raptis et al29 analyzed data from 355 patients with pancreatic cancer to evaluate whether a specific clinical presentation (abdominal pain, weight loss, jaundice) and delayed timing in referral, diagnosis, and treatment had any impact on the operability, resectability, and/or survival rate associated with pancreatic cancer. The researchers concluded that the time delay between referral and treatment had no significant impact on patient survival.
Abdominal pain is the presenting complaint in about half of all adult patients who seek primary care.30,31 This presentation is contestable in both primary care and specialty practice, such as gastroenterology, because it is usually a benign symptom; it can also be an indication of serious acute pathology32 (see “Case Patient”33,34).
In the study by Raptis et al,29 abdominal pain was the symptom with which patients affected by pancreatic cancer most commonly presented to primary care. Thus, it is important for the clinician to perform a thorough abdominal exam—inspection, auscultation, percussion, light touch, and deep palpation—on any patient with such symptoms. Deep palpation is specifically sensitive, since it can sometimes help the provider feel the abdominal organs, especially if they are enlarged. Opioids may be given if needed while the assessment proceeds.30
Other key points to include in the physical exam of a patient presenting with abdominal pain are vital signs, observation for jaundice (which in one study was reported in 41% of patients with pancreatic cancer25), chest auscultation and percussion, examination of the rectal, pelvic, and genitourinary regions, and an evaluation of mental status.31-33
Abnormal findings can help guide clinical decision making and treatment planning. It should be emphasized, however, that tumors of the pancreas can be difficult to detect and diagnose because of the anatomic location of the pancreas and the disease’s insidious properties.4,14