LWBK1006-18 LWW-Govindan-Review November 24, 2011 11:24
210 DeVita, Hellman, and Rosenberg’s CANCER: Principles and Practice of Oncology ReviewANSWERS
Answer 18.1. The answer is A.
EGFR overexpression is seen in 80% of lung cancers. However, EGFR
mutations occur in only 10% of NSCLCs, though these mutations are
found more frequently in Asian populations (40%), women, and never
smokers. EGFR mutations predict response to EGFR–tyrosine kinase
inhibitors. The most common mutations observed are an in-frame dele-
tion in exon 19 and a point mutation in exon 21 (L858R). These mutations
result in prolonged EGFR activation and downstream signaling.Answer 18.2. The answer is C.
Chromosome 3p allele loss is one of the most common events in the patho-
genesis of lung cancer, and is an early event. It occurs in 90% of SCLCs
and 80% of NSCLCs. HER2/neu is expressed in over a third of NSCLCs,
especially in adenocarcinoma. EML4–ALK translocations occur in 3%
to 5% of NSCLCs. Like EGFR mutations, these also are enriched in
never smokers. EML4–ALK translocations and EGFR mutations occur
in a mutually exclusive manner; tumors with EGFR mutations do not
have EML4–ALK translocations and vice versa.Answer 18.3. The answer is B.
The right upper lobe mass is suspicious for malignancy, however, a tis-
sue diagnosis is needed. Since the location of the mass is peripheral, the
best way to approach it would be through CT-guided biopsy, rather than
bronchoscopy and biopsy. Once a diagnosis of lung cancer is established,
staging studies, such as CT of the abdomen, MRI of the brain, PET, or
bone scan may be performed. If the diagnosis is NSCLC, and there is
no evidence of distant metastases on staging studies, then he should be
referred to a thoracic surgeon for discussion regarding surgical interven-
tions.Answer 18.4. The answer is D.
The seventh edition of the TNM staging system includes several changes
to the T descriptors including the addition of size cutoffs, of 2, 3, 5,
and 7 cm, subdivision of T1 into T1a and T1b, and of T2 into T2a and
T2b, downstaging of separate tumor nodules in the same lobe as the pri-
mary tumor from T4 to T3, downstaging of separate tumor nodules in a
different ipsilateral lobe as the primary tumor from M1 to T4, and reclas-
sification of malignant pleural nodules, pleural effusions and pericardial
effusions as M1 disease. He has stage IV disease due to the presence of
malignant pleural effusion and should receive treatment with platinum-
based doublet chemotherapy for metastatic disease. Surgery would be
appropriate only for early-stage disease, while chemoradiation would be
the way to treat locally advanced, stage III disease, in patients with good
PS and no significant weight loss.