Relationship between the three-dimensionally measured tumor doubling time of lung cancer and underlying interstitial lung disease: A retrospective case-control study

Abstract

Objective: The coexistence of interstitial lung disease (ILD) is associated with poor prognosis in patients with lung cancer. The tumor doubling time (TDT) of lung cancer reflects cancer aggressiveness and is related to its prognosis. However, the relationship between the TDT of lung cancer and underlying ILD has not been fully evaluated. This study aimed to identify this crucial relationship. Materials and Methods: Patients with lung cancer who underwent surgery between 2007 and 2020 were reviewed retrospectively. The propensity score matching method was used to balance the characteristics of patients with ILD (n = 100) and those without ILD (n = 100). TDT was calculated based on the difference of three-dimensional volumes defined from the two-time CT scans before surgery. We compared the TDT of lung cancer and other characteristics between the two groups. Results: The median TDT of all patients was 149 days. The TDT was significantly shorter in patients with ILD (134 days) than in those without (204 days). The rate of short-term tumor enlargement (TDT < 90 days) was significantly higher in patients with ILD than in those without ILD, and ILD was an independent factor related to short-term tumor enlargement (odds ratio, 2.30; p = 0.015). We focused on 25 patients with usual interstitial pneumonitis (UIP) findings of patients with ILD. However, the presence of the UIP pattern was not related to the TDT among patients with ILD. Conclusion: ILD was an independent predictor of short-term tumor enlargement in lung cancer patients, regardless of the presence of the UIP pattern.

Keywords

• Lung cancer
• Tumor doubling time
• Interstitial lung disease
• Malignancy