ADDITIONAL NODE RETRIEVAL OPTIMIZE STAGING IN NSCLC 

July 17, 2012 — A thorough lymph node examination can enhance the detection of unexpected metastatic disease in patients with nonsmall-cell lung cancer (NSCLC), but current practices are suboptimal, new research suggests.

The findings from a study by Raymond U. Osarogiagbon, MBBS, FACP, from the multidisciplinary thoracic oncology program at the University of Tennessee Cancer Institute, in Germantown, and colleagues were published online July 9 in the Journal of Clinical Oncology.

"Current methods of pathologic examination of lung cancer are woefully inadequate," Dr. Osarogiagbon toldMedscape Medical News. "About 150% more lymph nodes are left unexamined than are examined; consequently, most lymph nodes with metastases are not detected, leaving patients open to the danger of severely underestimated risk for long-term postoperative cancer-related death," he said.

In their previous studies, the researchers found that deficiencies are occurring in the operating room, and that making small changes in the procedure could enhance some aspects of surgical staging. Intrapulmonary lymph node examination, however, predominantly reflects pathology practice and, unlike other aspects of lung cancer management, it is not standardized.

In their current prospective case–controlled study, Dr. Osarogiagbon and colleagues evaluated the method pathologists used to handle the specimens. They examined lung-resection specimens from 73 consecutive patients with NSCLC at a single institution in Tennessee.

After routine pathologic examination of the tissue, remnant specimens underwent special pathologic examination instead of being destroyed, as is typical for these specimens.

Additional lymph nodes were dissected in 66 (90%) of the 73 specimens, and metastasis was detected in 56 of 514 (11%) retrieved lymph nodes from 27% of patients. Six of 50 (12%) node-negative patients had unexpected metastasis, and 3 other patients had undetected satellite metastatic nodules. Final pathologic tumor stage was upgraded in 8 (11%) of the 73 specimens.

"Four of 8 patients whose stage was upgraded became eligible for postoperative adjuvant chemotherapy because of [special pathologic examination] findings," the researchers report.

"Of greatest concern is the finding of unexamined [lymph node] metastasis in 12% of the 50 patients deemed to have node-negative disease after [routine pathologic examination]," Dr. Osarogiagbon and colleagues note.

"We suggest adoption of an improved protocol for dissection and examination of lung-resection specimens designed to improve [lymph node] yield," they conclude.

"Although more meticulous and labor intensive than [routine pathologic examination], our timed analysis shows that the [special pathologic examination] learning curve can be surmounted after a few patient cases."

Patients Seem to Be Understaged

Patients "with early-stage lung cancer in the Memphis area seem to be understaged as a result of both the surgical technique used and the management of the specimen by the pathology laboratories," writes Kemp Kernstine, MD, PhD, professor and chair of the division of thoracic surgery at the University of Texas Southwestern Medical Center in Dallas, in an accompanying editorial.

"The lack of a consistent approach to evaluation of the surgical specimen likely introduces significant variability in the staging process," he notes.

"To help improve the quality of lung cancer surgery, referring physicians and cancer specialists should critically review operative and pathology reports," he explains.

Study Is Relatively Unique

Independent commentator Philip Cagle, MD, from the Department of Pathology and Genomic Medicine at The Methodist Hospital Research Institute in Houston, Texas, noted that this study is "relatively unique" because it focuses on N1 lymph nodes from lung cancer lobectomy specimens.

"It is important for pathologists to take note of this study," he said, "and consider the importance of thorough lymph node sampling from a lobectomy specimen."

According to Dr. Cagle, lymph node sampling will likely become increasingly important as second-generation targeted therapies are developed for lung cancer.

Death Rates After Surgery Still High

"Lung cancer patients who undergo lobectomy generally do so because they are believed to have early-stage lung cancer that can potentially be cured by surgery. However, about one third of patients with stage I lung cancer and up to one half of patients with stage II lung cancer die of their cancer within 5 years," Dr. Cagle toldMedscape Medical News.

"It is important for the characterization, including staging, of these cancers to be as accurate as possible, not only for current prognosis and therapies, but also for potential future targeted therapies," he noted.

Current Practices Should Be Revised

Juan Wisnivesky, MD, professor of general internal medicine at the Mount Sinai School of Medicine in New York City, told Medscape Medical News that this study adds to the literature by showing that detailed evaluation of a surgical sample can also help identify additional positive lymph nodes.

"These results, if validated in other studies, suggest that current practices should be revised. It would be interesting to show that patients who are upstaged based on these additional findings do worse," Dr. Wisnivesky said. "It is expected, but should be assessed.

J Clin Oncol. Published online July 9, 2012. Abstract, Editorial