Comparative analysis of the 7th and 8th TNM staging with long-term outcomes in non-small cell lung cancer

Abstract

Objectives: This study aims to clinically validate 8^th tumor, node, metastasis (TNM) staging for lung cancer on previously operated cases to evaluate its potential to achieve homogeneous patient groups and predict survival.

Patients and methods: Between January 2009 and December 2016, 425 patients (356 males, 69 females; mean age: 61.5±9.4 years; range, 14 to 83 years) with non-small cell lung cancer were included in the study. Statistical evaluation was made by staging the postoperative pathological TNM according to the 7^th and 8^th TNM staging and comparing these two groups. All cases were evaluated according to the pathological TNM data obtained after the operation. The cases were staged twice according to the pathology results reports, by the 7^th and 8^th TNM. The distribution of patients in these two groups according to T parameter, N parameter, and stage is given. When staging changed, distribution changes between patient groups were evaluated. The survival distribution between the 7^th and 8^th stage groups was evaluated with the 5-year survival data obtained during follow-up.

Results: No change was observed in any parameters or stages of 148 of 425 cases (34.8%) with the 8^th staging classification. When classifying according to the 8^th TNM in the T parameter, it was observed that there was a transition to advanced T between the groups. When the N parameter is examined; 63.5% (n=270) N0 cases, 27.5% (n=117) N1 cases, and 8.9% (n=38) N2 cases were detected. When the T parameter remained the same, the cases whose stage increased due to the nodal parameter were 9.4% (n=40), and the cases whose stage increased due to both the increase in the T parameter and the nodal parameter were found to be 6.8% (n=29). The cases whose stage increased because the T parameter had changed were 29.6% (n=126), and the cases whose stage did not change even though the T parameter increased in the 8^th stage were 5.9% (n=25). When the general stage of the patients who underwent surgery is evaluated according to the 8^th TNM, it is seen that a new case distribution emerges in the Stage IIIB group. It was determined that 14 (3.3%) cases passed from Stage IIIA to IIIB with 8^th TNM, with a 5-year survival rate of 28.6%. Stage IIB group is the largest group with 125 (29.4%) cases, and when the subgroup differences between the two stagings are eliminated and the overall survival rates are compared, according to the 8^th TNM, 17.9% (p=0.006) five-year survival increase were observed for Stage IIB cases.

Conclusion: The main changes that should be underlined in the 8^th TNM staging, particularly for the patient group undergoing surgery, can be summarized as differentiation of survival expectancy in the early stage by increasing the tumor size subgroups in early-stage lung cancer without lymphatic metastasis, with tumor size becoming important in advancing the T parameter, emphasizing the need for systemic treatment by classifying N1 nodal metastasis as Stage IIB, being included in the T4 group, which is also known as the ‘locally advanced’ disease group, not only by anatomical invasion but also solely for the tumor size. It appears that the 8^th TNM reveals the effects of tumor size on stage in a more effective distribution.

Cite this article as: Yardımcı H, Ustaalioğlu R, Aydemir B, Yıldırım M, Okay T. Comparative analysis of the 7^th and 8^th TNM Staging with long-term outcomes in non-small cell lung cancer. D J Med Sci 2024;10(1):1-10. doi: 10.5606/fng. btd.2024.140.

The study protocol was approved by the Dr. Siyami Ersek Research and Training Hospital Ethics Committee Ethics Committee (date: 20.06.2017, no: 28001928-051.99). The study was conducted in accordance with the principles of the Declaration of Helsinki.

A written informed consent was obtained from the patients and/or parents of the patients.

Data Sharing Statement:
The data that support the findings of this study are available from the corresponding author upon reasonable request.

Writing, data collection, design: H.Y.; Conceptualization, design: R.U.; Data curation, critical review: B.A.; Critical review, control: M.Y.; Control, supervision: T.O.

The authors declared no conflicts of interest with respect to the authorship and/or publication of this article.

The authors received no financial support for the research and/or authorship of this article.