Pushback on Rule for Surgical Lymph Node Sampling During Lung Resection

SAN ANTONIO — Thoracic surgeons were fired up about minimum expectations for surgical lymph node assessment in conjunction with lung cancer resection during a debate at the Society of Thoracic Surgeons (STS) annual meeting.

The heart of the controversy was the legitimacy of the premise that more thorough lymph node sampling helps the accuracy of lung cancer staging so that patients can theoretically get the right treatment and ultimately live longer.

Frank Detterbeck, MD, of Yale School of Medicine in New Haven, Connecticut, took the stance that the American College of Surgeons Commission on Cancer (CoC) mandate of three mediastinal nodes (N2) plus one hilar node (N1) assessment (3N2+1N1) is the right standard for quality lung cancer surgery during any resection with curative intent.

“What we’re trying to get at is this poor-quality surgery,” he told the audience. “We have significant room for improvement. I think [3N2+1N1] is a very good standard. I think it certainly is better than what is out here broadly.”

Lymph node staging is an established prognostic factor for resected non-small cell lung cancer (NSCLC), and the extent of node evaluation correlates with overall survival. However, lung cancer physicians are known to vary in the thoroughness and accuracy of clinical nodal staging, as one study from 2018 in NSCLC reported that just 40% of surgical resections were in compliance with the three guidelines and about a quarter of patients didn’t have a single mediastinal lymph node included in their pathology report.

While Detterbeck said he did not believe node removal in itself improves outcomes, it is a “surrogate marker for someone who’s thoughtful in their care.”

Detterbeck’s opponent in the STS debate, Raja Flores, MD, of Mount Sinai Health System in New York City, stressed that the CoC standards were built on observational studies that, at best, provide arguments for association, not causation, between lymph node dissection and survival. The same foundational studies also showed high complication rates from doing these evaluations just to find a few N2 nodes that were unsuspected.

As for where the idea of 3N2+1N1 comes from, he found it first mentioned in a 1996 paper based on x-rays.

“3N2+1N1 evidence is weak and outdated. Complications happen,” he emphasized. In the current era of personalized medicine in which physicians are trying to tailor the treatment to a particular patient, 3N2+1N1 is akin to going back to a “one-size-fits-all” paradigm, he said. “Our surgical approach should take into account tumor size” and be tailored “to the patient, not the CoC.”

Flores pointed to lobe-specific nodal dissection as a potentially better strategy since lymph node metastasis tends to be lobe-specific. LESSON, a Chinese randomized trial, is currently trying to compare lobe-specific lymph node dissection with systematic lymph node dissection in early-stage NSCLC, and there is other work being done in Japan, he said.

He complained that amid all this research, the CoC is still mandating its blanket version of nodal assessment.

“I agree with Raja that if you have a mostly ground-glass tumor, we know the incidence of nodal involvement is very low with those,” Detterbeck said. “I don’t think there’s any benefit to extensive nodal dissection in that case.”

“The biggest issue to me with a standard is how do we apply this? If we’re trying to bring up the floor across the country, if we think it is useful, then having a standard is good. Does that apply to every case? Every institution?” Detterbeck posed. He said he personally has trouble with taking a standard and applying it to every institution and every individual surgeon. “I don’t know how far we can take that.”

Before the debate, Benjamin Resio, MD, of Memorial Sloan Kettering Cancer in New York City, presented institutional data from over 9,000 pulmonary resections for clinical stage I-III lung malignancies showing that before CoC standards went into effect January 2021, CoC-concordant sampling was associated with greater upstaging but did not lead patients to more appropriate adjuvant therapy and ultimately less cancer recurrence and improved survival in stage I and II. A potential survival benefit was detected in stage III, however.

“The present data raise questions about the validity of the current CoC guidelines as a surgical quality metric for resections of clinical stage I and II primary lung malignancies. Further study is warranted to determine the impact on clinical stage III patients and the potential differences in survival in the era of immune and targeted adjuvant therapies,” Resio told the audience. He noted that at his institution, operators have become highly compliant with CoC standards since implementation.

“In the majority of cases, we need to do a better job with lymph node sampling,” maintained panelist Timothy Mullett, MD, of the University of Kentucky in Lexington, a member of the group that developed the CoC standard. “As far as the type of dissection you choose to do … you can do lobe-specific and meet the standard.”

Mullett suggested that 3N2+1N1 is not a final rule and encouraged people to add quality data for future consideration. “For now, we needed to start with something global, working for all surgeons, all cancer, so I think this is a fair place for us to start.”

At the end of the debate, STS session moderator Linda Martin, MD, MPH, of the University of Virginia in Charlottesville, asked the full room for a show of hands on who won the debate. Flores was declared the winner after a quick, informal count.

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