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Proposed tumor classification criteria appears accurate for non-small cell lung cancer
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Proposed residual tumor classification criteria from International Association for the Study of Lung Cancer, or IASLC, appeared accurate among patients with non-small cell lung cancer, according to data presented at IASLC World Conference on Lung Cancer.
The residual tumor classification, also referred to as R status, includes proposed criteria for uncertain resection margin, or R(un).
“[Although] more data collection will be necessary to see the full impact in a clinical setting, our confirmation of the IASLC’s proposed criteria is an important step,” John G. Edwards, PhD, MB ChB, FRCS(C/Th), consultant thoracic surgeon in the department of thoracic surgery at Northern General Hospital in the United Kingdom, said during a press conference.
Edwards and colleagues analyzed existing and potential R status classification for 14,712 patients undergoing NSCLC surgery from the IASLC Lung Cancer Staging Project. Researchers evaluated R status criteria and other variables including the number of N2 stations explored, lobe-specific systematic lymph node dissection, extra-capsular extension, status of the highest station, bronchial carcinoma in situ at bronchial resection margin and pleural lavage cytology.
Researchers reassigned patients to the revised categories of R0, R(un), R1 and R2 status and determined their impact on survival.
Initial assignment classified 14,293 cases as R0; 263 cases as R1; and 156 cases as R2. Median survival was not reached for the R0 group, was 33 months for the R1 group and 29 months for the R2 group (P < .0001).
R status correlated with T and N stages (P < .0001).
Researchers analyzed 9,290 cases for three or more N2 stations and 6,619 cases for lobe-specific systemic lymph node dissection. These domains were positively associated with increasing pN2 stage (P < .0001).
Extracapsular extension occurred among 61 of 304 node-positive cases. The highest station tested positive in 942 cases (6.4%).
Pleural lavage cytology tested positive in 59 of 1,646 cases (3.6%), and bronchial carcinoma in situ at bronchial resection margin occurred in 13 cases.
After reassignment based on the IASLC proposed criteria, researchers classified 6,103 cases as R0, 8,203 cases as R(un), 250 cases as R1 and 156 cases as R2.
“When we look at how cases were assigned to uncertain category, the vast majority were due to lymph node dissection technique being less rigorous, and that was in 95% of the cases,” Edwards said. “It’s also important to realize we didn’t have the ultimate holy grail of the highest lymph node being involved.”
Among node-positive cases, median survival was 70 months for patients with R0 status, 50 months for R(un) status, 30 months for R1 status and 23 months for R2 status.
Among R(un) cases with positive high station, the median survival was 14 months shorter than with negative high station. Among node-positive cases, median survival was 20 months shorter than R0 cases.
“The numbers in the other categories are quite small which leads to the need in the future for getting very high-quality data into the database,” Edwards said. “Hence, that is the drive the staging committee will be making to ensure all institutions put in the highest-quality data that we can to allow us to evaluate these further in the future.
“If we want to show our survival rates on an institutional basis are the very best, we need to do our best to ensure we do good lymph node dissection and perform high-quality surgery,” Edwards added. – by Melinda Stevens
Reference:
Edwards JG, et al. Abstract 10325. Presented at: International Association for the Study of Lung Cancer World Conference on Lung Cancer; Oct. 15-18, 2017; Yokohama, Japan.
Disclosures: HemOnc Today could not confirm the authors’ relevant financial disclosures at the time of publication.