[Impact of the depth of remission by induction chemotherapy on the prognosis of limited stage small cell lung cancer]

Objective: To evaluate the effect of depth of remission of induction chemotherapy on the overall prognosis of limited stage small cell lung cancer (L-SCLC). Methods: The study was a retrospective, L-SCLC patients who contained complete imaging data and underwent consecutive standardized treatments at the Department of Thoracic Radiation and Medical Oncology, Zhongnan Hospital of Wuhan University between January 2013 and June 2021 were included. To delineate the volume of tumor before and after induction chemotherapy and to calculate the depth of remission caused by the induced chemotherapy. The time receiver operating characteristic (timeROC) method was used to determine the optimal predictors for prognosis, multi-factor analysis using Cox risk proportional model. Results: A total of 104 patients were included in this study. The median PFS and OS of this cohort were 13.7 months and 20.9 months, respectively. It was observed by timeROC analysis that residual tumor volume after induction chemotherapy had the optimal predictive value of PFS at 1 year (AUC=0.86, 95% CI: 0.78~0.94) and OS at 2 years (AUC=0.76, 95% CI: 0.65~0.87). Multivariate analysis showed residual tumor volume after induction chemotherapy was the independent prognostic factor to PFS (HR=1.006, 95% CI: 1.003~1.009, P<0.01) and OS (HR=1.009, 95% CI: 1.005~1.012, P<0.001). For those whose residual tumor volume remitted to less than 10 cm(3) after induction chemotherapy, the favorable long-term outcomes could be achieved, regardless of their initial tumor load. Conclusion: The depth of remission of induction chemotherapy could be a promising prognostic predictor to the L-SCLC and provide the individualized treatment guidance.

Optimal timing of thoracic irradiation for limited stage small cell lung cancer: Current evidence and future prospects

Lung cancer is a global health concern as the leading cause of cancer related mortality worldwide. Small cell lung cancer (SCLC) poses a formidable challenge to the treating physicians with the worst prognosis among all lung cancers. However, limited stage SCLC (LS-SCLC) has a relatively better outcome with multimodality management. Efforts have been focused on optimal integration of treatment modalities to achieve an improved therapeutic ratio for patients with LS-SCLC. While chemotherapy and thoracic radiation therapy (TRT) are primary components of initial management for LS-SCLC, there is no consensus on optimal timing of TRT. Within this context, we herein provide a concise overview of current evidence and future prospects regarding the optimal timing of thoracic irradiation for LS-SCLC in light of the literature.

Utility of Prophylactic Cranial Irradiation for Limited Stage Small Cell Lung Cancer in the Modern Era with Magnetic Resonance Imaging Surveillance

AIMS

To retrospectively analyse the impact of prophylactic cranial irradiation (PCI) on survival and intracranial progression in patients with limited stage small cell lung cancer (LS-SCLC) in the modern era of widespread magnetic resonance imaging brain screening.

MATERIALS AND METHODS

Patients with LS-SCLC treated within our network between 2009 and 2020 who responded to initial therapy were stratified by receipt of PCI and stage of disease. A propensity score match analysis was carried out for stage II-III patients. Overall and neurological survival were defined as time to death and presumed death due to uncontrolled intracranial disease, respectively. Brain metastasis-free survival and symptomatic brain metastasis-free survival were defined as freedom from intracranial progression and symptomatic intracranial progression, respectively. The effect of PCI on these outcomes was assessed using Kaplan-Meier and Cox proportional hazards models.

RESULTS

In total, 243 (69.6%) of 349 patients received PCI. On multivariate analysis in the propensity matched stage II-III cohort, PCI was a significant predictor of improved neurological survival (hazard ratio 0.23, 95% confidence interval 0.08-0.65; P = 0.01), brain metastasis-free survival (hazard ratio 0.25, 95% confidence interval 0.12-0.51; P < 0.01) and symptomatic brain metastasis-free survival (hazard ratio 0.21, 95% confidence interval 0.08-0.55; P < 0.01), but not improved overall survival. Two-year neurological survival estimates within the propensity matched cohort were 96.8% (95% confidence interval 87.6-99.2%) with PCI and 77.2% (95% confidence interval 63.0-86.4%) without PCI and 1- and 2-year estimates of incidence of brain metastases were 3.9% (95% confidence interval 1.3-11.7%) and 11.7% (95% confidence interval 5.6-23.5%) in the PCI group and 31.6% (95% confidence interval 22.1-43.9%) and 40.4% (95% confidence interval 29.2-54.0%) in the no PCI group, respectively.

CONCLUSIONS

In the modern era of magnetic resonance imaging screening, PCI was associated with reduced incidence of intracranial progression in patients with stage II-III LS-SCLC who respond to initial therapy. This, importantly, translated to a decreased risk of neurological death within our propensity matched cohort, without significant improvement in overall survival.

Cost-effectiveness of prophylactic cranial irradiation with hippocampal avoidance in limited stage small cell lung cancer

BACKGROUND AND PURPOSE

Prophylactic cranial irradiation (PCI) in limited stage small cell lung cancer (LS-SCLC) prevents brain metastases and improves survival, with the potential for neurocognitive toxicity. RTOG0933 demonstrated that hippocampal avoidance (HA) during whole brain radiotherapy preserves neurocognition. This study's objective was to evaluate the cost-effectiveness of HA-PCI in LS-SCLC through decision analysis.

MATERIALS AND METHODS

A Markov model was developed to simulate the clinical course of LS-SCLC who received HA-PCI or conventional PCI (C-PCI). A willingness-to-pay threshold of $100,000/QALY was used. Incremental cost effectiveness ratio was calculated (ICER). Sensitivity analyses were performed to determine the parameter thresholds and to assess the robustness of the model.

RESULTS

In the base case scenario, HA-PCI is more cost-effective than C-PCI, with an ICER of $47,107/QALY. HA-PCI was preferred over C-PCI provided that the risk of developing brain metastases was not increased by at least 14%, or if neurocognitive dysfunction rates were reduced by at least 40%. HA-PCI was the cost-effective strategy in 68% of tested iterations in probabilistic sensitivity analysis.

CONCLUSION

This study demonstrates that HA-PCI is more cost-effective than C-PCI in LS-SCLC. Our results support the use of HA-PCI in this patient population, should results from RTOG0933 be confirmed by the ongoing NRGCC003 trial.