Clinical Non-Small Cell Lung Cancer Staging and Tumor Length Measurement Results From U.S. Cancer Hospitals

Comparison of radiological and pathological tumor sizes in resected non-small cell lung cancer

OBJECTIVES

In non-small cell lung cancer (NSCLC), T factor plays an important role in determining staging. The present study aimed to determine the validity of preoperative evaluation of clinical T (cT) factor by comparing radiological and pathological tumor sizes.

METHODS

Data for 1,799 patients with primary NSCLC who underwent curative surgery were investigated. The concordance between cT and pathological T (pT) factors was analyzed. Furthermore, we compared groups with an increase or decrease of ≥ 20% and groups with an increase or decrease of < 20% in the size change between preoperative radiological and pathological diameters.

RESULTS

The mean sizes of the radiological solid components and the pathological invasive tumors were 1.90 cm and 1.99 cm, respectively, correlation degree = 0.782. The group with increased pathological invasive tumor size (≥ 20%) compared with the radiologic solid component was significantly more likely female, consolidation tumor ratio (CTR) ≤ 0.5, and within cT1. Multivariate logistic analysis identified CTR < 1, cT ≤ T1, and adenocarcinoma as independent risk factors for increased pT factor.

CONCLUSION

The radiological invasive area of tumors with cT1, CTR < 1, or adenocarcinoma on preoperative CT may be underestimated compared with pathological invasive diameter.

Lung Cancer Staging: Imaging and Potential Pitfalls

Lung cancer is the leading cause of cancer deaths in men and women in the United States. Accurate staging is needed to determine prognosis and devise effective treatment plans. The International Association for the Study of Lung Cancer (IASLC) has made multiple revisions to the tumor, node, metastasis (TNM) staging system used by the Union for International Cancer Control and the American Joint Committee on Cancer to stage lung cancer. The eighth edition of this staging system includes modifications to the T classification with cut points of 1 cm increments in tumor size, grouping of lung cancers associated with partial or complete lung atelectasis or pneumonitis, grouping of tumors with involvement of a main bronchus regardless of distance from the carina, and upstaging of diaphragmatic invasion to T4. The N classification describes the spread to regional lymph nodes and no changes were proposed for TNM-8. In the M classification, metastatic disease is divided into intra- versus extrathoracic metastasis, and single versus multiple metastases. In order to optimize patient outcomes, it is important to understand the nuances of the TNM staging system, the strengths and weaknesses of various imaging modalities used in lung cancer staging, and potential pitfalls in image interpretation.

Role of visceral pleural invasion and tumor sizing at CT of resected NSCLC in clinical-radiological and pathological T agreement

OBJECTIVE

To describe in non-small cell lung cancer (NSCLC) the impact of visceral pleural invasion (VPI) and of tumor sizing assessed at computed tomography (CT) on the agreement between clinical-radiological and pathological T staging and its prognostic value.

METHODS

Patients affected by NSCLC treated by surgery in the period from January 2017 to September 2020 were retrospectively evaluated. Exclusion criteria were: (1) baseline CT not performed in our hospital; (2) failure of software segmentation at CT of the primary lesion. Clinical-radiological T (cT) was assessed at baseline CT, evaluating in particular T size by semi-automatic tool and VPI (cVPI) visually. Pathological T (pT) and VPI (pVPI) were recorded by pathological report and obtained after formalin-fixation and eventual elastic stain on surgical specimen. The agreement between cT and pT was evaluated by calculating the weighted kappa by Cohen (κ_w); the association between progression free survival (PFS) with both cT and pT was assessed by the Cox regression analysis.

RESULTS

The study included 84 NSCLC in 82 patients (median age 71 years, IQR 63-76 years; females 22/82, 27%). The agreement between cT and pT was poor (κ_w 0.302, 95%CI 0.158-0.447). The main causes of disagreement were CT oversizing (21%) and false positive cVPI (29%). A significant association was found between PFS and pT2-T3 (HR 2.75, 95%CI 1.21-6.25, p=0.015) but not with cT2-T3 (not retained in the model).

CONCLUSIONS

False positive cVPI and oversizing at CT are causes of disagreement between cT and pT in around one-third of resected NSCLC. PFS was significantly associated with pT but not with cT.

National Utilization, Survival, and Costs Analysis of Treatment Options for Stage I Non-Small Cell Lung Cancer: A SEER-Medicare Database Analysis

RATIONALE AND OBJECTIVES

To compare utilization, outcomes, and costs of surgery, radiation therapy, and percutaneous ablation for the treatment of stage I non-small cell lung cancer (NSCLC).

MATERIALS AND METHODS

Using 2006-2016 Medicare-linked Surveillance, Epidemiology, and End Results (SEER) databases, stage I NSCLC patients who underwent surgery, radiotherapy, or percutaneous ablation were identified using relevant billing codes. National utilization rates were determined. Overall survival for treatment arms were compared using log-rank test and Cox-proportional hazard modeling. Mean direct costs for each treatment strategy during the first year after diagnosis were compared using Analysis of Variance.

RESULTS

A total of 15,847 Stage I NSCLC patients were identified; mean age at diagnosis was 75.5 years (minimum age = 66 years) and 59.2% were female. A total of 10,732 patients (67.7%) underwent only surgery, 5013 (31.6%) only radiotherapy, and 102 (0.6%) only ablation. Utilization of surgery and ablation decreased while radiotherapy utilization increased from 2007 to 2015 (p < 0.0001). Compared to the ablation group, overall survival was greater for the surgery group (HR: 0.7, 95% CI of HR: 0.6-0.9, p = 0.0047) and lower for the radiotherapy group (HR: 1.4, 95% CI of HR: 1.1-1.8, p = 0.002). The mean first year cost of therapy for ablation = $11,976) was significantly less (p < 0.05) than for radiotherapy ($15,447) and surgery ($22,669).

CONCLUSION

In Medicare patients with stage I NSCLC, the utilization of radiation therapy has increased and surgery has declined, while utilization of percutaneous ablation has remained uniformly low. Although overall survival is best for surgery, then ablation, and then radiation therapy, first year treatment costs are lowest for ablation.