Residual Tumor ‘Uncertain’ Classification Validated in Non–Small Cell Lung Cancer


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After surgical resection of non–small cell lung cancer (NSCLC), investigators from the International Association for the Study of Lung Cancer (IASLC) have validated outcomes for tumors deemed to be of “uncertain” residual tumor status (ie, R[un]).

“The residual tumor (R) classification reflects the quality of surgery, has prognostic impact, and may affect further treatment. It is an important criterion in the interpretation of multimodality clinical trials,” explained John G. Edwards, MBChB, PhD, FRCS, of the University of Sheffield in the United Kingdom, speaking at a press briefing at the 2017 World Conference on Lung Cancer in Yokohama, Japan.


The residual tumor classification reflects the quality of surgery, has prognostic impact, and may affect further treatment. It is an important criterion in the interpretation of multimodality clinical trials.
— John G. Edwards, MBChB, PhD, FRCS

An IASLC subcommittee recently analyzed the proposed IASLC definition for R(un) status from data collected for the IASLC Lung Cancer Staging Project. They presented their findings at the World Conference on Lung Cancer.1

Project Details and Results

Of 14,712 patients with NSCLC undergoing surgery and who met all of their criteria for study, researchers obtained data on the various descriptors of R(un) status and the impact of any R status on survival. Cases were deemed R(un) “where there were criteria that potentially give rise to less than certain R margin status (ie, uncertain margins),” said Dr. Edwards.

Those were cases in which intraoperative lymph node staging was less rigorous than the standard of lobe-specific sentinel lymph node dissection, where the highest node or the bronchial resection margin showed carcinoma in situ (rather than invasive cancer) and where pleural lavage was positive, he explained.

R status correlated significantly with T and N stages and with survival. For patients with involved lymph nodes, median survival was 70 months for patients with R0 resection, 50 months for R(un) patients, 30 months for R1 patients, and 23 months for R2 patients.

Residual Tumor of ‘Uncertain’ Status

  • An analysis was performed on data collected from the IASLC Lung Cancer Staging Project, to better understand the occurrence of residual tumor deemed to be of “uncertain” status, labeled R(un).
  • In the analysis of almost 15,000 patients, more than half were labeled R(un). R(un) status was deemed a valid classification.
  • Prognosis for this subset of patients falls between the good prognosis of R0 patients and the worse prognosis of R1 and R2 patients.
  • Median survival for node positive R(un) patients was 50 months.

R(un) accounted for 56% of the cases. The majority of these cases were due to intraoperative staging being less rigorous than with sentinel lymph node dissection. In pN2 cases with the highest station being positive, median survival was 14 months less compared with the highest station–negative cases. In node-positive cases, median survival was 20 months less for patients with R(un) status compared with R0 status, he reported.

Based on their findings, the proposed criteria for R(un) were validated. The prognosis for these patients falls between that of R0 and R1, Dr. Edwards said.

Further detailed prospective data collection is required to fully characterize the prognostic impact of these criteria. Detailed evaluation of R status is of particular importance in the design and analyses of clinical trials of adjuvant therapies, he noted. ■ 

DISCLOSURE: Dr. Edwards reported no conflicts of interest.

REFERENCE

1. Edwards JG, Chansky K, Shemanski L, et al: The IASLC Lung Cancer Staging Project. 2017 World Conference on Lung Cancer. Abstract PL 02.06. Presented October 17, 2017.


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