LWBK1006-19 LWW-Govindan-Review December 7, 2011 21:24
Chapter 19•Neoplasms of the Mediastinum 227tumors and can be found in approximately 30% of patients in this set-
ting. A long-term survival rate of 16% has been reported for patients with
midline poorly differentiated carcinoma of unknown primary site treated
with cisplatin-based chemotherapy appropriate for NSGCT. The pres-
ence of i(12p) has been favorably associated with response and survival.
Because the International Germ Cell Cancer Collaborative Group con-
siders mediastinal NSGCT a “poor-risk” tumor, appropriate treatment
should consist of cisplatin, etoposide, and bleomycin for four cycles. Ther-
apy aimed at good-risk NSGCT (answer A), stage III NSCLC (answer C),
or lymphoma (answer D) would not be appropriate.Answer 19.15. The answer is D.
This young man had an excellent response to initial chemotherapy for
mediastinal NSGCT with normalization of tumor markers and a small
residual mediastinal mass. Mediastinal NSGSTs commonly arise in the
anterior compartment, and most patients are symptomatic at diagnosis.
Elevations of-hCG and-fetoprotein are found in 30% to 50% and
60% to 80% of patients, respectively. NSGCTs frequently consist of a
mixture of histologic subtypes, including choriocarcinoma, embryonal
carcinoma, endodermal sinus (yolk sac) elements, and teratoma. Primary
treatment of mediastinal NSGCTs is cisplatin, etoposide, and bleomycin,
as per the guidelines for poor-risk nonseminomatous testicular cancer,
which yields a complete response rate of 40% to 64% and a long-term
survival rate of 45%. Surgical resection is recommended for patients with
residual masses after completion of initial chemotherapy and normaliza-
tion of tumor markers. If viable NSGCT elements are identified in the
resected specimen, then two further cycles of cisplatin-based therapy are
indicated. If the residual mass reveals only mature teratoma or necrosis,
then clinical surveillance without further treatment is indicated. The role
of surgical resection in patients with incomplete tumor marker responses
has not been clearly defined, but such patients would typically proceed to
salvage chemotherapy with a regimen such as VIP.Answer 19.16. The answer is B.
This young man presents with a localized mediastinal seminoma. Pure
mediastinal seminoma is a rare disease, accounting for 35% of malig-
nant mediastinal germ cell tumors and occurring mainly in men 20 to
40 years of age. Despite their slow growth rate, mediastinal semino-
mas tend to present as large tumors that cause symptoms resulting from
compression of mediastinal structures. Serum-hCG and LDH levels may
be modestly elevated in patients with pure seminoma, but an elevated-
fetoprotein level would be indicative of a nonseminomatous germ cell
component. Radiotherapy is the treatment of choice for localized medi-
astinal seminoma, yielding long-term survival rates of 60% to 80%. The
total radiation dose should be in excess of 45 Gy, and the field should
include the mediastinum and bilateral supraclavicular fossae. Although
surgery followed by adjuvant therapy also yields high long-term survival
rates, resection is not generally indicated in the management of medi-
astinal seminoma. Because of the exquisite sensitivity of seminoma to