Cancer in a localized or systemic state is a frequent item in the differential diagnosis of a variety of common complaints. Although not all forms of cancer are curable at diagnosis, affording patients the greatest opportunity for cure or meaningful prolongation of life is greatly aided by diagnosing cancer at the earliest point possible 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 29-1).
TABLE 29-1Spectrum of Cancer-Related Interventions ||Download (.pdf) TABLE 29-1 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:
Staging the cancer: Where has it spread?
Palliative and end of life
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 the swelling that is a common physical manifestation of a tumor derives from increased interstitial fluid pressure and increased cellular and stromal mass per volume, compared to normal tissue. Tumors historically were referred to as carcinomas, or “crab-like” infiltrating tumors, or sarcomas, or “fleshy tumors,” derived from the Greek terms for “crab” and “flesh,” respectively. 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, as are decreases in the number of platelets and inappropriate inhibition of blood coagulation. 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, such as enlarged lymph nodes in lymphomas or a palpable mass ...