Background
Dispute arises in the tumor category of non-small cell lung cancer
(NSCLC) invading the fissure to the adjacent lobe. The purpose of this study
is to determine the long-term prognosis of NSCLC with such an invasion and
to propose an appropriate T category.
Methods
In total, 53 cases of NSCLC invading the fissure to the adjacent lobe
(Fissure group) was identified in patients that underwent pulmonary
resection from 1997 through 2014. Propensity score matching was applied to
balance known confounders for prognosis between each paired group, resulting
in three matched sets (Fissure vs. T2a, Fissure vs. T2b, and Fissure vs.
T3). The overall survival of the Fissure group was compared to those of
patients with T2a, T2b, and T3 diseases, as classified in the eighth edition
of TNM classification.
Results
The 5-years survival rates of T2a, T2b, T3 and the Fissure group were
64.2% (95% confidence interval, 53.2–72.6),
54.6% (95% confidence interval, 44.7–65.8),
35.8% (95% confidence interval, 22.8–44.2) and
38.6% (95% confidence interval, 25.0–52.2),
respectively. Specifically, the difference between the Fissure group and T2a
is statistically significant, p=0.01; between the Fissure group and
T2b, p=0.02; and between the Fissure group and T3, p=0.93.
Multivariate analyses indicate the Fissure group had a similar risk of dying
as the T3 disease (Hazard ratio 1.10, 95% confidence interval
0.69–1.37) and was at a significantly higher risk compared to the
T2a (Hazard ratio 2.34, 95% confidence interval 1.50–3.39)
and T2b diseases (Hazard ratio 1.71, 95% confidence interval
1.19–2.76 ).
Conclusions
Based on our single-institution study, we propose that NSCLC invading
the fissure to the adjacent lobe should be further investigated and the
impact on patient’s prognosis validated as a T3 disease.