SAN FRANCISCO– Positive regional lymph nodes are not an independent risk factor for death from adrenocortical carcinoma, finds a cohort study presented at the annual clinical congress of the American College of Surgeons.
“High tumor grade and distant metastasis were the only independent prognostic factors,” reported lead researcher Dr. Kun-Tai Hsu, a surgical resident formerly with the University of Wisconsin–Madison and currently at Michigan State University in East Lansing.
“While regional lymph node metastasis was not associated with worse outcome, it was associated with local tumor invasion. More importantly, regional lymph node status and local tumor invasion had equivalent impact on disease-specific mortality, but lymph node status was not a marker for local tumor invasion,” he added.
Using the Surveillance, Epidemiology, and End Results (SEER) database, the researchers analyzed data for 1,202 adults who underwent surgery for unilateral adrenocortical carcinoma between 1973 and 2010. A total of 10% had regional lymph node metastases, as ascertained by sampling, imaging, or both.
Median survival was 46 months for the cohort overall, and the 5-year rate of disease-specific mortality was 55%, Dr. Hsu reported. Patients with regional lymph node metastases had higher significantly disease-specific mortality in unadjusted analyses but not in adjusted analysis. However, high tumor grade and distant metastases were both strong independent risk factors (hazard ratios, 2.37 and 2.87).
Patients were more likely to have regional lymph node metastases if they had local invasion. When peers having neither of these factors were the comparator, risk was elevated for patients with only positive lymph nodes (HR, 9.9) and for patients with only local invasion (HR, 6.7), and most for patients having both factors (HR, 18.0).
“The effect appears to be additive rather than a true interaction,” commented Dr. Hsu, who disclosed that he had no conflicts of interest relevant to the research. “Therefore, there was no synergistic interaction between local tumor invasion and regional lymph node metastases: these two disease factors equally predict disease-specific mortality and are not simply a marker of one another.”
“We are aware that there are several limitations of the SEER database,” he acknowledged. “Nevertheless, given the rare nature of adrenocortical carcinoma, SEER provided enough data to have the statistical power and objectivity not available from single-institution studies.”
In an interview, session comoderator Dr. Amelia C. Grover of the Department of Surgery’s division of surgical oncology, Virginia Commonwealth University in Richmond, said that the findings reinforce earlier research on this cancer. “The problem is, adrenocortical carcinoma is such a uncommon disease, it makes drawing a large enough group difficult. So the SEER database was a great resource,” she agreed. “However, because of its limitations, it makes it hard to draw any significant conclusions, again stressing that for these unusual endocrine neoplasms, it’s really great to have collaborative efforts from multiple institutions in driving that research forward and collecting that data so that we can better care for those patients.”