Devita, Hellman, and Rosenberg's Cancer

LWBK1006-15 LWW-Govindan-Review December 7, 2011 19:5

178 DeVita, Hellman, and Rosenberg’s CANCER: Principles and Practice of Oncology Review

The role of imaging is to evaluate any extension of disease. Both CT

with contrast and MRI with contrast are used for staging of head and

neck cancers. The preference seems to vary by institution. For upper

aerodigestive malignancies, MRI is the favored technique because of

fewer artifacts from the skull base. PET/CT has become a valuable tool

in the staging of head and neck cancer. Although CT with intravenous

contrast is usually used initially, PET/CT with FDG but no intravenous

contrast allows for a nice complement. This is particularly true in the

postoperative neck, which can be confusing on routine CT or MRI. CT is

usually favored when early cortical base erosion is suspected or if invasion

of the orbital walls or paranasal sinus walls is the clinical question.

Answer 15.26. The answer is D.

Lung cancer is the most common cancer in both men and women, and

its incidence is increasing. Screening, therefore, has been a topic of a

great deal of discussion. Unfortunately, studies have not demonstrated

any improvement in mortality from chest radiograph screening, although

lesions were detected at more favorable stages. Studies are currently under

way to determine whether CT with its ability to detect smaller lesions will

be any better. It is still too early to tell whether detecting smaller lesions

will affect mortality from this dreaded disease. Another role of imaging

lung cancer is in the staging of disease. Despite improvements in spa-

tial resolution, CT is still limited in its ability to detect chest wall and

mediastinal invasion. MRI has shown greater promise in the evaluation

of tumor extension because of its improved multiplanar capability and

soft-tissue resolution. This is particularly true in the superior sulcus or

lung apex where MRI can delineate tumor involvement of the subcla-

vian vessels and brachial plexus better than CT. PET/CT is also useful in

the staging of lung cancer. It is better than CT alone in the detection of

mediastinal lymphadenopathy and sensitive for adrenal and bone metas-

tases. Because of its high sensitivity, PET/CT may overstage patients with

non-small cell lung cancer. Because of the high glucose uptake of normal

brain, PET/CT with FDG is limited for the evaluation of brain metas-

tases. If these are suspected clinically, further imaging with MRI may be

indicated.

Answer 15.27. The answer is B.

Adrenal glands represent the most common site of abdominal metastases

from lung cancer. For this reason, a routine chest CT should include the

adrenal glands. Most adrenal nodules in patients with lung cancer will be

adrenal adenomas. Because of their high lipid content, many (but not all)

will be low attenuating on noncontrast CT examinations. If intravenous

contrast is given, adenomas will enhance and may not be distinguishable

from metastases. Many adrenal adenomas will show signal dropout on

opposed phase gradient recalled echo imaging. PET may also be helpful

in adrenal imaging in that metastases should have increased uptake when

they are larger than 1 cm. Because of false positives with CT, PET, and

MRI, any patient with isolated suspected adrenal metastasis should be