JAMA: Ultrasound obviates some lung cancer staging surgeries, thoracotomies
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| CT scan of 72-year-old woman shows dominant pulmonary nodule (arrow) in right lower lobe that proved at pathology to be adenocarcinoma. Source: American Journal of Roentgenology, Ginsberg et al, 2004 |
"We have shown that performing endosonography to visualize the lymph nodes in patients with suspected non-small cell lung cancer (NSCLC) is at least as accurate as invasive surgical staging but results in fewer complications," Jonke T. Annema, MD, PhD, of the department of pulmonology at Leiden University Medical Center in Leiden, the Netherlands, told Health Imaging News. "The other thing we have shown," continued Annema, "is that if you first utilize the ultrasound approach and after, if no signs of metastasis are found, administer the surgical procedure, you can reduce unnecessary lung operations by half. This is a lot, and it will reduce morbidity for these operations."
Mediastinal nodal staging is recommended in patients with suspected resectable NSCLC to determine whether the cancer has metastasized to the lymph nodes. Mediastinal staging is typically performed by mediastinoscopy, an invasive surgical procedure requiring general anesthesia.
Current clinical guidelines acknowledge combined transesophagal (EUS-FNA) and endobronchial (EBUS-TBNA) ultrasound endoscopy as an alternative pre-operative staging technique, when negative findings are followed up by surgical staging. The authors noted, however, that "[a]t present it is not known whether initial mediastinal tissue staging of lung cancer by endosonography improves the detection of nodal metastases and reduces the rate of unnecessary thoracotomies."
The purpose of the study was to compare surgical staging of NSCLC with endosonography alone as well as to perform a combined evaluation of endosonography followed by surgical staging. Out of 240 patients, 123 were randomly assigned to undergo endosonography followed by surgical staging if endosonography results presented as negative; 117 patients were randomly selected to undergo surgical staging without endosonography.
Of the 123 patients who underwent endosonography, 58 were diagnosed with locally advanced disease and therefore required no follow-up surgery, with 56 of these cancers diagnosed as mediastinal nodal metastases and two as T4 cancers. The endosonography cohort's 65 remaining patients underwent surgical staging, in 59 of which no locally advanced disease was discovered, while the remaining six patients were diagnosed with locally advanced stage N2/N3 cancers.
These results yielded a stand-alone sensitivity for endosonography of 85 percent, versus 79 percent sensitivity for surgical staging. This difference was not statistically significant. On the other hand, the combined sensitivity of endosonography plus surgical staging measured 94 percent, significantly greater than the sensitivity wielded by standard surgical staging alone.
Within the 117-patient surgical staging only group, 42 patients were diagnosed with locally advanced cancer by surgical staging, with 70 of the remaining 75 patients undergoing thoracotomy. Of these thoracotomy patients, 16 additional locally advanced cases of cancer were discovered. In the 123-person endosonography cohort, 58 patients underwent thoracotomy, in whom six cases of locally advanced cancer were discovered.
The authors determined that 21 unnecessary thoracotomies were performed in the surgical staging group, compared with nine in the combined endosonography/surgical staging group.
"If you perform endoscopy with ultrasound alone, you have a sensitivity of 85 percent, which is better than surgery but not statistically significant, though the reduction in complications is statistically significant," noted Annema. "Now, if you perform ultrasound first and half of the patients have metastatic tumors, and then you perform the surgical staging after a negative ultrasound, you have a sensitivity of 94 percent. By using a combination of both methods, you cut unnecessary thoracotomies in half."
The authors acknowledged that the lack of a generally accepted definition of unnecessary thoracotomy posed a limitation of their study. Additionally, echoing the authors themselves, an accompanying editorial questioned the applicability of the study's findings given that endosonography requires substantial expertise and produces results that are highly operator dependent, wrote Mark D. Iannettoni, MD, MBA, of the University of Iowa Hospitals and Clinics in Iowa City. Thus, Iannettoni argued, endosonography's improved sensitivity may not be feasible in many community health centers, in which the majority of thoracic surgeries take place.
"This is a valid comment," Annema told Health Imaging News. Nevertheless, Annema countered by saying: "I think our results are accurately reproducible in these facilities. There's quite a body of evidence that endosonography can be implemented very well in community hospitals, provided that doctors there are accurately trained."
Anemma estimated that these community health physicians would require anywhere from 30 to 50 cases for training. "In Germany, for instance," Annema pointed out, "to qualify as a lung cancer center and receive reimbursement from insurance companies, you are required to perform endobronchial ultrasound (EBUS-TBNA).
"This study clearly indicates that if you need tissue samples from the nodes in your chest if you have lung cancer, you should start with endosonography. This is clear because endosonography's results were at least as strong as surgery's with fewer complications."
According to Annema, the critical issue now is not whether to perform endosonography for NSCLC, but how to proceed in patients with negative endosonography results. That is, whether patients should continue to undergo surgical staging for added sensitivity.
"You know that you have to investigate 11 patients to find a metastasis in one. The discussion in the pulmonary and thoracic community is whether this is worthwhile ... Future studies should focus on the patients with negative endosonographies, on determining which of them should undergo surgical staging."
In Annema's opinion, "having 11 patients undergo surgery to find a metastisis in just one is a lot." He cautioned, however, that this debate continues.
Annema concluded that "there is no question that endosonography will be a very important tool in the diagnosis and staging of lung cancer. It is only a matter of how quickly it can be implemented."