Lung Cancer.pdf

Pathologic Evaluation of Lung Cancer 61
other techniques are generally utilized for more peripherally located lesions.
Open lung biopsy is generally utilized for diagnosis of lesions that
do not yield sufficient tissue with use of the above-mentioned less invasive
procedures and for nonneoplastic lung disease.
Bronchial brushing, bronchial washing, and fine-needle aspiration
biopsy yield single cells or small groups of cells that are evaluated by a cytopathologist.
Bronchial brushing and bronchial washing are performed
endoscopically, while fine-needle aspiration biopsy is done under direct
imaging guidance. During the acquisition of these specimens, a cytopathologist
is usually on hand to comment on whether the specimen is
adequate for establishing the diagnosis and to divide the specimen for different
diagnostic and research tests. At M.D. Anderson Cancer Center, the
cytopathology laboratory is located adjacent to the interventional radiology
suite to facilitate the expeditious analysis of fine-needle aspirates obtained
under imaging guidance. This close working relationship between
the cytopathologists and radiologists benefits patients by reducing the
number of procedures they must undergo to have the diagnosis of lung cancer
established and by reducing the time needed to establish the diagnosis.
Endobronchial biopsy and transbronchial biopsy yield small pieces of
tissue, usually measuring less than 5.0 mm in maximal dimension. Core
needle biopsy yields a tissue fragment that measures approximately 1.0
mm in diameter, with a length of 5.0 mm to 20.0 mm depending on the
type of needle and the technique employed.
Occasionally the mediastinal lymph nodes are examined as part of the
preoperative evaluation to confirm the diagnosis of metastatic disease in
clinically suspicious lymph nodes to help plan treatment. The lymph
nodes are either sampled using fine-needle aspiration biopsy or removed
in their entirety during mediastinoscopy.
Especially in the case of a limited tissue sample, it may not be possible
to accurately classify a lung cancer before surgery except with regard to its
being small cell carcinoma or NSCLC (Edwards et al, 2000). The difficulty
of subclassifying NSCLC on the basis of small tissue samples is due to the
well-known morphologic heterogeneity of lung cancer. However, as the
recommended treatment for patients with NSCLC does not differ on the
basis of histologic subtype, rendering the diagnosis of NSCLC in a biopsy
specimen is usually adequate.
Intraoperative Evaluation
At M.D. Anderson, intraoperative pathologic evaluation is an important
component of the surgical management of lung cancer. Frozen section examination
is routinely performed to evaluate the bronchial margin of
lobectomy and pneumonectomy specimens, to establish the diagnosis of
nodules detected incidentally at the time of surgery, and to evaluate regional
lymph nodes. Sometimes, the soft tissue margins of a chest wall resection
specimen may also be examined using the frozen section technique.