Pam Harrison

November 06, 2015

 

Virtually all granulomatous lymph nodes that show up as hypermetabolic on CT or PET scans during the preoperative staging of non-small-cell lung cancer are negative for metastases, and further exploration is probably unnecessary, a pilot study suggests.

"We came into this thinking that if lymph nodes do have calcification, they are less likely to have a metastatic process going on," said Chad Hruska, MD, a resident at the University of Tennessee Medical Center in Knoxville.

"The whole idea was that if we could find some way that radiologists could better predict whether a lymph node was going to be positive or negative for metastatic disease based on the radiologic findings, then they could sample only the lymph nodes that they think are going to be positive," Dr Hruska told Medscape Medical News. "It's more accurate staging overall, which is just better for patients."

The study was presented at the American Society for Clinical Pathology 2015 Annual Meeting in Long Beach, California.

Dr Hruska and his colleagues reviewed electronic pathology records for a 20-year period, and identified 106 cases of stage I to III non-small-cell lung cancer resections with concomitant granulomatous lymph nodes.

Histologic sections from 1671 lymph node fragments were examined for the presence of metastases and granulomatous disease.

Granulomatous Disease

Granulomatous disease was identified in 422 lymph nodes.

Of these, 416 tested negative for metastasis on Fisher's exact test. In fact, only six granulomatous lymph nodes contained metastatic carcinoma.

And the metastases identified in these six granulomatous lymph nodes involved only portions of the lymph nodes that were not replaced by the granulomatous process.

Of the granulomatous lymph nodes identified, 212 demonstrated fibrotic changes and 210 demonstrated fibrocalcific changes.

In contrast, 44 of the 1249 nongranulomatous lymph nodes identified on review contained metastases.

It is possible that granulomatous lymph nodes are so rarely metastatic because they mount some sort of antitumor response that makes them inhospitable to metastatic disease, Dr Hruska explained.

"We've also been thinking that if a patient has a granuloma, the granuloma could obstruct the spread of metastatic disease, so it's harder for the cancer to invade the lymph node," he said.

These findings could have significant diagnostic, sampling, and therapeutic implications for patients with non-small-cell lung cancer, sparing them further exploration with fine-needle aspiration or other procedures to rule out the presence of metastatic disease in the lymph node, Dr Hruska and his colleagues conclude.

Dr Hruska has disclosed no relevant financial relationships.

American Society for Clinical Pathology (ASCP) 2015 Annual Meeting. Presented October 30, 2015.

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