Efficacy of Definitive Radiotherapy for Patients with Clinical Stage IIIB or IIIC Lung Adenocarcinoma and Epidermal Growth Factor Receptor (EGFR) Mutations Treated Using First- or Second-Generation EGFR Tyrosine Kinase Inhibitors.

Background: The effectiveness of definitive radiotherapy (RT) for patients with clinical stage IIIB or IIIC lung adenocarcinoma and epidermal growth factor receptor (EGFR) mutations who received first- or second-generation EGFR tyrosine kinase inhibitors (TKIs) is unclear. Methods: Taiwan Cancer Registry data were used in this retrospective cohort study to identify adult patients diagnosed with EGFR-mutated stage IIIB or IIIC lung adenocarcinoma between 2011 and 2020. Patients treated with first- or second-generation EGFR TKIs were classified into RT and non-RT groups. Propensity score (PS) weighting was applied to balance covariates between groups. The primary outcome was overall survival (OS), and the incidence of lung cancer mortality (ILCM) was considered as a supplementary outcome. Additional supplementary analyses were conducted to assess the robustness of the findings. Results: Among 270 eligible patients, 41 received RT and 229 did not. After a median follow-up of 46 months, PS-weighted analysis showed the PS-weighted hazard ratio of death for the RT group compared to the non-RT group was 0.94 (95% CI: 0.61-1.45, p = 0.78). ILCM rates did not differ significantly between the two groups. Supplementary analyses yielded consistent results. Conclusion: The addition of definitive RT to first- or second-generation EGFR TKI treatment does not significantly improve OS of patients with EGFR-mutated stage IIIB or IIIC lung adenocarcinoma. NCT03521154NCT05167851.

Neoadjuvant Chemotherapy With/Without Radiotherapy for Locally Advanced Rectal Cancer: A Nationwide Retrospective Cohort Study.

BACKGROUND/AIM: The role of neoadjuvant radiotherapy in the management of patients with locally advanced rectal cancer (LARC) who have undergone neoadjuvant systemic therapy has been the subject of recent debate. PATIENTS AND METHODS: We identified eligible rectal cancer patients diagnosed between 2011 and 2020 using data from the Taiwan Cancer Registry. In our primary analysis, we applied propensity score weighting (PSW) to balance observable potential confounders. We then compared the hazard ratio (HR) of death the neoadjuvant concurrent chemoradiotherapy (nCCRT) group and the neoadjuvant chemotherapy without radiotherapy (nCT) group. Additionally, we conducted a comprehensive assessment of other outcomes and performed various supplementary analyses. RESULTS: The primary analysis included 2,298 patients. The overall survival did not exhibit statistically significant differences, with a PSW-adjusted HR of 0.72 (95% confidence interval=0.33-1.56, p=0.40) when comparing the nCCRT group to the nCT group. These findings were consistent with those of other long-term outcomes and supplementary analyses. CONCLUSION: In patients with LARC who have undergone neoadjuvant systemic therapy, the addition of radiotherapy did not yield statistically significant differences in long-term clinical outcomes.

Health Economic Evaluation of Proton Therapy for Lung Cancer: A Systematic Review.

BACKGROUND: To our knowledge, there have been no systematic reviews of health economic evaluations of proton therapy specific to lung cancer. METHODS: We conducted this systematic review according to the predefined protocol [PROSPERO CRD42022365869]. We summarized the results of the included studies via structured narrative synthesis. RESULTS: We identified four studies (all used passively scattered proton therapy) from 787 searches. Two cost analyses reported that proton therapy was more costly than photon therapy for early- or locally advanced-stage non-small cell lung cancer, one cost-utility analysis reported that proton therapy was dominated by nonproton therapy in early-stage non-small cell lung cancer, and one cost-utility analysis reported that proton therapy was not cost-effective (vs. photon) in locally advanced non-small cell lung cancer. CONCLUSIONS: Passively scattered proton therapy was more costly and not cost-effective than photon therapy for early- and locally advanced-stage non-small cell lung cancer. Further health economic evaluations regarding modern proton therapy (such as scanning beam) for common radiotherapy indications of lung cancer are eagerly awaited.

High vs. low radiotherapy dose in locally advanced esophageal squamous cell carcinoma patients treated with neoadjuvant concurrent chemoradiotherapy: an endemic area population-based study.

BACKGROUND: The optimal radiotherapy dose for locally advanced esophageal squamous cell carcinoma in endemic areas treated with neoadjuvant concurrent chemoradiotherapy is unclear. METHODS: Eligible patients diagnosed between 2010 and 2019 were identified via the Taiwan Cancer Registry. We used propensity score (PS) weighting to balance observable potential confounders. The hazard ratio (HR) of death was compared between high dose (50-50.4 Gy) and low dose (40-41.4 Gy) radiotherapy. We also evaluated other outcomes and performed supplementary analyses via an alternative approach. RESULTS: Our study population consisted of 644 patients. The PS weight-adjusted HR of death was 0.92 (95% confidence interval: 0.7-1.19, p = 0.51). There were no statistically significant differences for other outcomes or supplementary analyses. CONCLUSIONS: In this population-based study from an endemic area, we found no significant difference in overall survival between high vs. low radiotherapy doses.

Consolidative chemotherapy after definitive concurrent chemoradiotherapy for esophageal squamous cell carcinoma patients: a population based cohort study.

BACKGROUND: The role of consolidative chemotherapy (CCT) for locally advanced esophageal squamous cell carcinoma (LA-ESCC) patients treated with definitive concurrent chemoradiotherapy (dCCRT) is unclear. We aimed to compare the overall survival (OS) of those treated with vs without CCT via a population based approach. METHODS: Eligible LA-ESCC patients diagnosed between 2011 and 2017 were identified via the Taiwan Cancer Registry. We used propensity score (PS) weighting to balance observable potential confounders between groups. The hazard ratio (HR) of death and incidence of esophageal cancer mortality (IECM) were compared between those with vs without CCT. We also evaluated the OS in supplementary analyses via alternative approaches. RESULTS: Our primary analysis consisted of 368 patients in whom covariates were well balanced after PS weighting. The HR of death when CCT was compared to without was 0.67 (95% confidence interval 0.52-0.86, P = 0.002). The HR of IECM was 0.66 (P = 0.04). The HR of OS remained similarly in favor of CCT in supplementary analyses. CONCLUSIONS: We found that CCT was associated with significantly improved OS for LA-ESCC patients treated with dCCRT. Randomized controlled trials were needed to confirm this finding.

Effectiveness evaluation of adjuvant concurrent chemoradiotherapy for patients with positron emission tomography-staged esophageal squamous cell carcinoma after complete resection: A population-based cohort study.

BACKGROUND: The role of adjuvant concurrent chemoradiotherapy (ACCRT) is unclear for patients with esophageal squamous cell carcinoma (ESCC) who receive esophagectomy with clean margins. We compared the survival of the ACCRT versus observation groups for these patients staged with positron emission tomography (PET) via a population-based approach. METHODS: Eligible patients with locally advanced ESCC diagnosed between 2011 and 2017 were identified via the Taiwan Cancer Registry. We used propensity score (PS) weighting to balance observable potential confounders between groups. The hazard ratios (HR) of death and incidence of esophageal cancer mortality (IECM) were compared between the ACCRT and observation groups. We also evaluated overall survival (OS) in subgroups of either with or without lymph node metastases. RESULTS: Our primary analysis consisted of 105 patients in whom the covariates were well balanced after PS weighting. The HR for death when ACCRT was compared with observation was 0.58 (95% confidence interval 0.28-1.21, p = 0.15). The results were also not significantly different for IECM or in the subgroup analyses. CONCLUSION: We found that for patients with PET-staged ESCC who received esophagectomy with clean margins, the survival was not statistically different between ACCRT and observation. Further studies (randomized or larger sample size) are needed to clarify this issue.

Adjuvant Concurrent Chemoradiotherapy Versus Adjuvant Chemotherapy Only in Locally Advanced Non-small-cell Lung Cancer With Involved Microscopic Resection Margin: A Population-based Cohort Study.

BACKGROUND/AIM: The role of adjuvant concurrent chemoradiotherapy (aCCRT) for locally advanced non-small cell lung cancer (LA-NSCLC) treated with radical surgery, with microscopically involved resection margin, has been debated without there being any direct evidence. In this study, we aimed to compare the outcomes between aCCRT and adjuvant chemotherapy (aCT). PATIENTS AND METHODS: Eligible patients diagnosed within 2011-2018 with LA-NSCLC were identified via the Taiwan Cancer Registry. We used propensity-score weighting to balance observable potential confounders, and then compared the hazard ratios of death between aCCRT-treated vs. aCT-treated groups. We also performed supplementary analyses using propensityscore matching. RESULTS: Our main study population consisted of 82 patients. The propensity score weight-adjusted hazard ratio of death for the aCCRT group was 0.74 (95% confidence interval=0.35-1.56, p=0.43). There was also no statistically significant difference in survival between groups in the supplementary analyses. CONCLUSION: For patients treated with radical but R1 resection for LA-NSCLC, there was no significant OS benefit from the addition of concurrent radiotherapy.

High vs. Standard Radiotherapy Dose in Locally Advanced Rectal Adenocarcinoma Patients Treated With Neoadjuvant Long Course Chemoradiotherapy: A Population-based Study.

BACKGROUND/AIM: Locally advanced rectal cancer (LARC) patients are often treated with neoadjuvant long course chemoradiotherapy (NLCCRT) using 45-50.4 Gy conventional fractionated radiotherapy (CFRT). The role of radiotherapy dose escalation is unclear. PATIENTS AND METHODS: We identified LARC patients diagnosed from 2011 to 2016 and treated with NLCCRT using CFRT at high dose (54-60 Gy) or standard dose (45-50.4 Gy). In the primary analyses, we used propensity score (PS) weighting to balance the observable potential confounders. The hazard ratio (HR) of death and other endpoints were compared. We also evaluated these outcomes in supplementary analyses via an alternative approach. RESULTS: Our primary analysis included 459 patients. The HR of death when high dose was compared with standard dose was 0.62 (p=0.51). There were also no statistically significant differences in other endpoints or in the supplementary analyses. CONCLUSION: Overall, survival of LARC patients treated with NLCCT in CFRT was not significantly different between high or standard dose.

Optimal radiotherapy dose in cervical esophageal squamous cell carcinoma patients treated with definitive concurrent chemoradiotherapy: A population based study.

BACKGROUND: The optimal radiotherapy dose for locally advanced cervical esophageal squamous cell carcinoma (C-ESqCC) treated with definitive concurrent chemoradiotherapy (dCCRT) is unclear. Here, we aimed to compare the survival of those treated with high dose versus standard dose via a population based approach. METHODS: Eligible C-ESqCC patients diagnosed between 2011 and 2017 were identified via the Taiwan Cancer Registry. We used propensity score (PS) weighting to balance observable potential confounders between groups. The hazard ratio (HR) of death and incidence of esophageal cancer mortality (IECM) were compared between high (60-70 Gy) and standard dose (50-50.4 Gy). We also evaluated the outcome in supplementary analyses via alternative approaches. RESULTS: Our primary analysis consisted of 141 patients in whom covariates were well balanced after PS weighting. The HR of death when high dose was compared with standard dose was 0.65 (95% confidence interval [CI]: 0.4-1.03, p = 0.07). The HR of IECM was 0.74 (p = 0.45). The HR of OS remained similarly insignificant in supplementary analyses. CONCLUSIONS: We observed a trend in favor of high radiotherapy dose versus standard dose for C-ESqCC treated with dCCRT in this population-based nonrandomized study. Further studies are needed to confirm the findings of the study.

Effectiveness of Image-Guided Radiotherapy in Adjuvant Radiotherapy on Survival for Localized Breast Cancer: A Population-Based Analysis.

PURPOSE: Image-guided radiotherapy (IGRT) is an advanced radiotherapy technique to improve the radiotherapy delivery. We aimed to compare the overall survival (OS) for localized breast cancer (LBC) patient treated with adjuvant conventional fractionated radiotherapy (CFRT) using IGRT vs those without IGRT via a population-based analysis. PATIENTS AND METHODS: Eligible LBC patients diagnosed between 2011 and 2013 were identified via the Taiwan Cancer Registry. We used propensity score (PS) weighting to balance observable potential confounders between groups. The hazard ratio (HR) of death and other outcomes were compared between IGRT and non-IGRT. We also evaluated OS in various supplementary analyses. RESULTS: Our primary analysis included 6490 patients in whom covariates were well balanced after PS weighing. The HR for death when IGRT was compared with non-IGRT was 1.02 (95% confidence interval 0.80-1.31, P = 0.86). There were also no significant differences in the supplementary analyses. CONCLUSION: We found that OS of LBC patients treated with adjuvant CFRT was not statistically different between those treated with IGRT versus without IGRT. This was the first study in this regard to our knowledge but randomized controlled trials were needed to confirm our finding.

Chemotherapy alone versus definitive concurrent chemoradiotherapy for cT4b esophageal squamous cell carcinoma: a population-based study.

BACKGROUND: The role of radiotherapy for cT4bNanyM0 esophageal squamous cell carcinoma (ESqCC) is relatively unclear, with both chemotherapy (C/T) alone and definitive concurrent chemoradiotherapy (dCCRT) being treatment options in the current guidelines. We aimed to compare the survival of dCCRT versus C/T for these patients via a population-based approach. METHODS: Eligible cT4b ESqCC patients diagnosed between 2011 and 2017 were identified via the Taiwan Cancer Registry. We used propensity score (PS) weighting to balance the observable potential confounders between groups. The hazard ratio (HR) of death and incidence of esophageal cancer mortality (IECM) were compared between dCCRT and C/T. We also evaluated OS in subgroups of either low or standard radiotherapy doses. RESULTS: Our primary analysis consisted of 247 patients in whom covariates were well balanced after PS weighing. The HR for death when dCCRT was compared with C/T was 0.36 (95% confidence interval 0.24-0.53, P < 0.001). Similar results were found for IECM. Statistical significance was only observed in the standard RT dose but not in the low dose in subgroup analyses. CONCLUSIONS: In this population-based nonrandomized study of cT4bNanyM0 ESqCC patients from Asia (Taiwan), we found that the use of radiotherapy with chemotherapy was associated with better overall survival than chemotherapy alone. Further studies (especially RCTs) are needed to confirm our findings.

Safety of image-guided radiotherapy in definitive radiotherapy for localized prostate cancer: a population-based analysis.

OBJECTIVES: Image-guided radiotherapy (IGRT) is a recommended advanced radiation technique that is associated with fewer acute and chronic toxicities. However, one Phase III trial showed worse overall survival in the IGRT arm. The purpose of this observational study is to evaluate the impact of IGRT on overall survival. METHODS: We used the Taiwan Cancer Registry Database to enroll cT1-4N0M0 prostate cancer patients who received definitive radiotherapy between 2011 and 2015. We used inverse probability treatment weighting (IPW) to construct balanced IGRT and non-IGRT groups. We compared the overall survival of those in the IGRT and non-IGRT groups. Supplementary analyses (SA) were performed with alternative covariates in propensity score (PS) models and PS approaches. The incidence rates of prostate cancer mortality (IPCM), other cancer mortality (IOCM), and cardiovascular mortality (ICVM) were also evaluated. RESULTS: There were 360 patients in the IGRT arm and 476 patients in the non-IGRT arm. The median follow-up time was 50 months. The 5-year overall survival was 88% in the IGRT arm and 86% in the non-IGRT arm (adjusted hazard ratio [HR] of death = 0.93; 95% CI, 0.61-1.45; p = 0.77). The SA also showed no significant differences in the overall survival between those in the IGRT and non-IGRT arms. Both groups did not significantly differ in terms of IPCM, IOCM, and ICVM. CONCLUSIONS: The overall survival of localized prostate cancer patients who underwent IGRT was not inferior to those who did not. ADVANCES IN KNOWLEDGE: We demonstrated that the overall survival for prostate cancer patients with IGRT was not worse than those who did not undergo IGRT; this important outcome comparison has not been previously examined in the general population.

Focal conformal fractionated radiotherapy vs. radiosurgery for lung cancer patients with limited brain metastases.

BACKGROUND: For lung cancer (LC) patients with limited brain metastases (LBM), radiosurgery (RS) was the current preferred strategy. We aimed to report our experience regarding an alternative strategy (focal conformal fractionated radiotherapy, FCFRT) for these patients in this cohort study. METHODS: We identified LC patients with LBM treated with either FCFRT or RS within 2016-2019 without prior brain local treatment via in-house databases. The characteristics of patients, disease, treatment, and outcome were retrospectively obtained via chart review and peer review. The 1st day of FCFRT or RS was the index date. Overall survival (OS) was calculated from the index date to the last date of contact or death via the Kaplan-Meier method. Log-rank test was used in univariate analyses (UVA) whereas Cox regression method was used in the multivariate analyses (MVA). The incidence of local progression (LP) or distal brain metastases (DBM) was estimated by the competing risk approach with death as the competing risk. RESULTS: We identified 23 eligible patients. The median dose/fractionation for FCFRT was 36 Gy/10 fractions. The median dose for RS was 20 Gy. The Lung-molGPA prognostic groups' distribution for these two groups was not statistically different. After a median follow-up of 8 months (range, 1-38 months), the OS was not statistically different in UVA [P value 0.9]. The adjusted hazard ratio of death was 0.96 when FCFRT was compared to RS in MVA (95% CI, 0.21-5.22). There was also no statistical significant difference in LP (P value 0.79) or DBM (P value 0.88). CONCLUSIONS: For LC patients with LBM, the OS was not statistically different for definitive FCFRT or RS. There was also no statistical difference in LP or DBM. Further studies should be considered to clarify the indication of FCFRT.

Effectiveness of image-guided radiotherapy for locally advanced lung cancer patients treated with definitive concurrent chemoradiotherapy.

BACKGROUND: Image-guided radiotherapy (IGRT) is an advanced radiotherapy technique to improve the precision and accuracy of treatment delivery. A recent randomized controlled trial (RCT) for prostate cancer patients treated with radiotherapy via either IGRT or routine care reported statistically significantly worse overall survival (OS) for those patients treated with IGRT. This raised the concern regarding the effectiveness of IGRT in definitive concurrent chemoradiotherapy (dCCRT) for locally advanced lung cancer (LALC). METHODS: Eligible LALC patients diagnosed between 2011 and 2016 were identified via the Taiwan Cancer Registry. We used propensity score (PS) weighting to balance observable potential confounders between groups. The hazard ratio (HR) of death and other outcomes were compared between IGRT and non-IGRT. We also evaluated OS in various subgroups. RESULTS: Our primary analysis consisted of 797 patients in whom covariates were well balanced after PS weighing. The HR for death when IGRT was compared with non-IGRT was 0.96 (95% confidence interval 0.79-1.15, P = 0.65). There were also no significant differences for most of the other outcomes or subgroup analyses. CONCLUSIONS: In this updated nonrandomized study, we found that OS of LALC patients treated with dCCRT was not statistically different between those treated with IGRT versus non-IGRT. The results should be interpreted with caution given the nonrandomized design. Studies regarding toxicity, local control, or designed as RCT are needed to clarify the role of IGRT. KEY POINTS: SIGNIFICANT FINDINGS OF THE STUDY: The OS of LALC patients treated with dCCRT was not statistically different between those treated with IGRT versus those without IGRT, although the observed HR for death was less than unity (ie, in favor of IGRT). WHAT THIS STUDY ADDS: In this updated nonrandomized study using real world data with additional potential confounders, our study provided a reasonable tentative evidence in the lack of RCT as suggested in the literature.

Clinical Outcomes and Prognostic Factors of Patients With Esophageal Squamous Cell Carcinoma With Oligo-recurrence Treated With Radical Re-irradiation.

BACKGROUND: For patients with esophageal squamous cell carcinoma (ESCC) with oligo-recurrence (OR) after previous curative radiotherapy and not eligible for radical resection, the role of radical re-irradiation was not clear. Therefore, we aimed to investigate the outcome and prognostic factors of such patients. PATIENTS AND METHODS: We identified patients with OR of ESCC after previous curative radiotherapy and were treated with radical re-irradiation within 2012-2018 via an in-house prospectively established database. The characteristics of patients, disease, treatment, and outcome were retrospectively obtained via chart review. The first day of re-irradiation was defined as the index date. Overall survival was calculated via the Kaplan-Meier method. Log-rank test was used for univariate analysis and Cox regression method was used for multivariable analysis. RESULTS: We identified thirty patients for analyses. After a median follow-up of 9 (range=2-76) months, the 5-year overall survival rate was 21%. Four patients with possible radiotherapy-related complication in need of inpatient care were identified. Gross tumor volume was the only significant prognostic factor in both univariate and multivariable analyses. CONCLUSION: We found that radical definitive re-irradiation may lead to one-fifth long-term survivors of patients with OR after previous curative radiotherapy for ESCC, and the gross tumor volume was the only significant prognostic factor for these patients. Randomized controlled trials should be considered to compare radical re-irradiation with the current standard of care (systemic therapy) for this population.

Effectiveness of image-guided radiotherapy for locally advanced esophageal squamous cell carcinoma patients treated with definitive concurrent chemoradiotherapy.

BACKGROUND: Image-guided radiotherapy (IGRT) is an advanced radiotherapy technique to improve the accuracy of treatment delivery. However, a recent randomized controlled trial (RCT) for prostate cancer patients treated with radiotherapy either via IGRT or routine care (no daily IGRT) reported a statistically significant worse overall survival for those treated with IGRT. This raised the concern regarding the effectiveness of IGRT for definitive concurrent chemoradiotherapy (dCCRT) for locally advanced esophageal squamous cell carcinoma (LA-ESqCC). METHODS: Eligible LA-ESqCC patients diagnosed between 2011 and 2015 were identified via the Taiwan Cancer Registry. We estimated propensity scores to construct a 1:1 propensity-score-matched groups and balance observable potential confounders. The hazard ratio (HR) of death as well as other outcomes was compared between IGRT and non-IGRT matched groups during the entire follow-up period. The impact of additional covariables was considered in the sensitivity analysis. RESULTS: Our study population included 590 patients in the primary analysis. The HR for death when IGRT was compared with non-IGRT was 0.92 (95% confidence interval 0.77-1.10, P = 0.35). There were also no significant differences for other outcomes or sensitivity analyses. CONCLUSIONS: In this updated nonrandomized study using real world data, we found that the overall survival of LA-ESqCC patients treated with dCCRT was not statistically different between those treated with IGRT versus those without IGRT, although the hazard ratio was less than unity, ie, in favor of IGRT. The results should be interpreted with caution given the nonrandomized design and RCTs are needed to clarify our findings. KEY POINTS: Significant findings of the study: The OS of LA-ESqCC patients treated with dCCRT was not statistically different between those treated with IGRT versus those without IGRT, although the hazard ratio was less than unity, ie, in favor of IGRT. WHAT THIS STUDY ADDS: In this updated nonrandomized study using real world data with additional potential confounders, our study provided a reasonable tentative evidence of lack of RCT as suggested in the literature.

Comparative effectiveness of simultaneous integrated boost vs sequential intensity-modulated radiotherapy for oropharyngeal or hypopharyngeal cancer patients: A population-based propensity score-matched analysis.

There were 2 common radiotherapy dose fractionation strategies in head-and-neck cancer patients (such as oropharyngeal cancer [OPC] or hypopharyngeal cancer [HPC]) treated with radiotherapy: intensity-modulated radiotherapy using simultaneous integrated boost (IMRT-SIB) and sequential IMRT (IMRT-SEQ). There is a lack of high-level clinical evidence to compare IMRT-SIB vs IMRT-SEQ specifically for OPC or HPC patients. The present study investigated the survival outcomes of OPC or HPC patients receiving definite concurrent chemoradiotherapy (CCRT) with either IMRT-SIB or IMRT-SEQ via a population-based propensity score (PS)-based analysis.The localized stage OPC or HPC patients diagnosed between 2011 and 2015 were identified based on the Health and Welfare Data Science Center database in Taiwan. These patients received definitive CCRT with either IMRT-SIB or IMRT-SEQ. We constructed a PS-matched cohort (1:1 for IMRT-SIB vs IMRT-SEQ) to balance observable potential confounders. We compared the hazard ratio (HR) of death between IMRT-SIB and IMRT-SEQ during the entire follow-up period. We also evaluated other disease outcome or subgroups.Our study population constituted 200 patients with well balance in observed covariables. The HR of death when IMRT-SIB was compared to IMRT-SEQ was 1.23 (95% confidence interval 0.84-1.80, P = .29). The results were similar for other disease outcome or subgroups.We found the survival outcome might be comparable for those treated with IMRT-SIB vs those treated with IMRT-SEQ.

Impact of the interval between neoadjuvant concurrent chemoradiotherapy and esophagectomy in the modern era: a population-based propensity-score-matched retrospective cohort study in Asia.

BACKGROUND: Neoadjuvant concurrent chemoradiotherapy (nCCRT) is one of the standard-of-care options for locally advanced esophageal squamous cell carcinoma (LA-ESqCC). The optimal interval between nCCRT and esophagectomy is unknown. METHODS: We constructed a propensity-score-matched [1:1 for long (8-12 weeks) vs short (4-7 weeks) intervals] cohort of LA-ESqCC patients who were diagnosed from 2011 to 2015 and treated with nCCRT via the Taiwan Cancer Registry and related databases. We compared the hazard ratios (HRs) of death using a robust variance estimator. We also evaluated alternative covariables, outcomes, and interval definitions. RESULTS: Our study population included 80 patients for each group; groups were balanced with respect to the observed covariables. There was no significant difference for the HR of death [1.22; 95% confidence interval 0.78-1.91, P = 0.39] when the long interval group was compared to the short interval group. There were also no significant differences when alternative covariables, outcomes, or interval definitions were evaluated. CONCLUSIONS: In this population-based study in modern Asia, we found that for LA-ESqCC patients treated with nCCRT and esophagectomy, overall survival was similar for either long or short intervals between nCCRT and esophagectomy. Randomized controlled trials are needed to verify this finding.

Effectiveness of image-guided radiotherapy for rectal cancer patients treated with neoadjuvant concurrent chemoradiotherapy: A population-based propensity score-matched analysis.

AIM: The effects of image-guided radiotherapy (IGRT, an advanced RT technology) have been debated in the literature. We compared the outcomes of locally advanced rectal cancer (LARC) patients treated with neoadjuvant concurrent chemoradiotherapy (NCCRT; with vs without IGRT) in a large population-based propensity score (PS)-matched analysis. METHODS: We identified LARC patients diagnosed between 2007 and 2015 via the Taiwan cancer registry (TCR) and constructed a PS-matched cohort to balance observable potential confounders. Outcomes (R0 resection, overall survival, incidence of local regional recurrence [ILRR], rectal cancer mortality [IRCM], other cancer mortality [IOCM] and cardiovascular mortality [ICVM]) were obtained from TCR and the national death registry. We compared the hazard ratio (HR) of death and other endpoints between IGRT and non-IGRT groups. We performed supplementary analysis (SA) to evaluate the robustness of these results in a subgroup, taking an additional potential confounder into account. RESULTS: Our study population comprised of 586 patients that were balanced with regard to observed covariables. There was no significant difference in HR for death (0.99; 95% confidence interval 0.70-1.39; P = 0.94) between IGRT and non-IGRT groups. There were also no significant differences in R0 resection, ILRR, IRCM, IOCM or ICVM. The results of our SA were consistent with these findings. CONCLUSION: For LARC patients treated with NCCRT, the treatment outcome was not significantly different among patients treated with and without IGRT. Further study is needed to clarify these results with consideration to additional potential confounding factors and toxicity profiles at endpoints.