Internal-Medicine

132 6: Oncology
25. (B) Barrett’s esophagus, characterized by a
columnar cell-lined esophageal mucosa, is a
major risk factor for adenocarcinoma of the
esophagus. Although acid reflux may be a predisposing
factor, there is no evidence that either
medical or surgical antireflux measures alter the
outcome. It is found in about 20% of patients
undergoing endoscopy for esophagitis, and up
to 50% may develop a malignancy. (Kasper, p. 222)
26. (D) Worldwide, the presence of liver flukes
(e.g., Clonorchis sinensis) is the most likely predisposing
factor for cholangiocarcinoma. Part
of this increased risk is caused by the development
of hepatolithiasis. The highest rate of
cholangiocarcinoma is found in Southeast Asia.
It is thought that liver flukes and a diet high in
nitrosamine are the prime reasons for this. In
North America, primary sclerosing cholangitis
and chronic ulcerative colitis are the most
common predisposing factors. Cholelithiasis,
alcohol, smoking, and chronic hepatitis B are
not known to be risk factors. (Kasper, p. 536)
27. (E) The size of the tumor is a prognostic factor, as
is knowing menopausal status, endocrine receptor
status, and lymph node involvement. These
four factors are used to decide who will benefit
from adjuvant chemotherapy, radiotherapy, or
tamoxifen treatment. (Kasper, pp. 520–522)
28. (A) Observation alone is adequate for this lesion.
The “ABCD” rules are helpful in distinguishing
benign skin lesions from malignant melanoma.
(A) asymmetry, benign lesions are symmetric;
(B) border irregular, most nevi have clear-cut
borders; (C) color variation, benign lesions
have uniform color; (D) diameter, >6 mm is
more likely to be malignant. In addition, recent
rapid change in size is also helpful in distinguish
benign from malignant lesions.
Thickness of the tumor is the most important
prognostic factor in the majority of cases, and
ulceration indicates a more aggressive cancer
with a poorer prognosis. Although cumulative
sun exposure is a major factor in melanoma
(e.g., more frequent near the equator), it cannot
explain such things as the more common occurrence
of some types in relatively young people.
It is possible that brief, intense exposure to
sunlight may contribute to, or initiate, carcinogenic
events. (Kasper, pp. 500–502)
29. (B) Prognosis of patients with non-Hodgkin’s
lymphoma is best assessed with the
International Prognostic Index. It is an index
with five clinical risk factors that helps to predict
the 5-year survival. Poor prognostic factors
are age >60 years, high serum LDH level, poor
performance status (either Eastern Cooperative
Oncology Group [ECOG] >2, or Karnofsky
1 extranodal
involvement. (Kasper, p. 647)
30. (A) IgG spikes >3.5 g/dL or IgA >2 g/dL
strongly suggest myeloma rather than monoclonal
gammopathies of undetermined significance
(MGUS). MGUS is suggested when the
spike is