Localized or systemic cancer is frequent in the differential diagnosis of a variety of common complaints. Although not all forms of cancer are curable at initial diagnosis, affording patients the greatest opportunity for cure or meaningful prolongation of life is greatly aided by diagnosing cancer early in its natural history, and defining treatments that prevent or retard its systemic spread. Indeed, certain forms of cancer, notably breast, colon, and possibly lung cancers in certain patients, can be prevented by screening appropriately selected asymptomatic patients; screening is arguably the earliest point in the spectrum of possible cancer-related interventions where cure is possible (Table 69-1).
TABLE 69-1Spectrum of Cancer-Related Interventions ||Download (.pdf) TABLE 69-1 Spectrum of Cancer-Related Interventions
Screening for cancer in an asymptomatic patient
Consideration of cancer in a differential diagnosis
Physical examination, imaging, or endoscopy to define a possible tumor
Diagnosis of cancer by biopsy or removal:
Specialized histology: immunohistochemistry
Staging the cancer: Where has it spread?
During treatment: related to tumor effects on patient
During treatment to counteract side effects of treatment
Palliative and end of life
When useful treatments are not feasible or desired
The term cancer, as used here, is synonymous with the term tumor, whose original derivation from Latin simply meant “swelling,” not otherwise specified. We now understand that swelling as a common physical manifestation of a tumor reflects increased interstitial fluid pressure and increased cellular and stromal mass per volume, compared to normal tissue. Leukemias are a special case of a cancer of the blood-forming tissues presenting in a disseminated form frequently without definable tumor masses. In addition to localized swelling, tumors present by altered function of the organ they afflict, such as dyspnea on exertion from the anemia caused by leukemia replacing normal hematopoietic cells, cough from lung cancers, jaundice from tumors disrupting the hepatobiliary tree, or seizures and neurologic signs from brain tumors. Hemorrhage is also a frequent presenting sign of tumors involving hollow viscera, but also may reflect decreases in the number of platelets or altered blood coagulation. Tumors may also present owing to the effects of substances they secrete called a “paraneoplastic” syndrome. Thus, although statistically the fraction of patients with cancer underlying a particular presenting sign or symptom may be low, the implications for a patient with cancer of missing an early-stage tumor call for vigilance; therefore, persistent signs or symptoms should be evaluated as possibly coming from an early-stage tumor.
Evidence of a tumor’s existence can objectively be established by careful physical examination, detecting enlarged lymph nodes in lymphomas or a palpable mass in a breast or soft tissue site. A mass may also be detected or confirmed by an imaging modality, such as plain x-ray, computed tomography (CT) ...