Real-world Survival Comparisons between Radiotherapy and Surgery for Metachro-nous Second Primary Lung Cancer and its Lung Cancer-specific Outcome Predictions by Machine Learning: Population-Based Study
ABSTRACT
Background:
Metachronous second primary lung cancer (MSPLC) occurs not very rarely but is seldom studied.
Objective:
We aim to compare real-world survival outcomes between different surgery strategies and radiotherapy for MSPLC.
Methods:
This retrospective study analyzed patients with MSPLC from the Surveillance, Epidemiology, and End Results database between 1988 and 2012. Propensity score matching (PSM) analyses and machine learning were performed between patients with MSPLC. Survival curves were plotted using Kaplan-Meier method and were compared by log-rank test.
Results:
A total of 2451 MSPLC patients were categorized into treatment groups: 864 (35.3%) re-ceived radiotherapy, 759 (31.0%) underwent surgery, 89 (3.6%) had surgery plus radio-therapy, and 739 (30.2%) had neither treatment. After propensity score matching (PSM), 470 pairs each for radiotherapy and surgery were generated. The surgery group exhibited significantly better survival than the radiotherapy group (P < .001) and the untreated group (563 pairs; P < .001). Further analysis revealed that both wedge resection (85 pairs; P < .004) and lobectomy (71 pairs; P < .002) outperformed radiotherapy in overall survival for MSPLC patients. Machine learning models (XGB, RFC, ADB) demonstrated high predictive per-formance with AUC values. LASSO regression identified nine significant variables impacting Cancer-Specific Survival, emphasizing surgery’s consistent influence across 1 to 10 years. These variables encompassed age at diagnosis, sex, year of diagnosis, radiotherapy of IPLC, primary site, histology, surgery, chemotherapy, and radiotherapy of MPSLC. Com-peting-risk analysis highlighted lower mortality in female MPSLC patients (HR = 0.79, 95% CI: 0.71-0.87) and recent IPLC diagnoses (HR = 0.79, 95% CI: 0.73-0.85), while radiotherapy for initial lung cancer increased mortality (HR = 1.31, 95% CI: 1.16-1.50). Surgery alone had the lowest cancer-specific mortality (HR = 0.83, 95% CI: 0.81-0.85), with sublevel resection having the lowest mortality rate among surgical approaches (HR = 0.26, 95% CI: 0.21-0.31). The findings provide valuable insights into the factors that influence cumulative can-cer-specific mortality.
Conclusions:
Surgical resections such as wedge resection and lobectomy confer better survival than radiation therapy for MSPLC, but radiation can be a valid alternative choice in the treatment of MSPLC.
Citation
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