Increased Biological Effective Dose of Radiation Correlates with Prolonged Survival of Patients with Limited-Stage Small Cell Lung Cancer: A Systematic Review

The Dose/Fractionation Debate in Limited-Stage Small Cell Lung Cancer

To explore the most suitable dosage regimen for limited-stage small cell lung cancer (LS-SCLC) and provide references for clinical selection, strict inclusion criteria were applied, and studies were screened from Pubmed, Embase, and Web of Science. Subsequently, data on two-year overall survival rates and dosage regimens were collected, and scatter plots were constructed to provide a comprehensive perspective. The survival benefits of various dosage regimens were evaluated, and a linear quadratic equation was utilized to fit the relationship between the biologically effective dose (BED10) and the two-year overall survival rate. Among the five randomized controlled trials, the two-year overall survival rate of ConvTRT regimens with BED10 > 60 Gy (rough value) was only at or below the median of all ConvTRT regimens or all included study regimens, indicating that increasing the number and total dose of ConvTRT does not necessarily lead to better prognosis. In the exploration of HypoTRT regimens, there was a linear positive correlation between BED10 and the two-year overall survival rate (p < 0.0001), while the exploration of HyperTRT regimens was relatively limited, with the majority focused on the 45 Gy/30 F regimen. However, the current 45 Gy/30 F regimen is not sufficient to control LS-SCLC, resulting in a high local recurrence rate. High-dose ConvTRT regimens have long treatment durations and may induce tumor regrowth which may cause reduced efficacy. Under reasonable toxicity reactions, HyperTRT or HypoTRT with higher radiotherapy doses is recommended for treating LS-SCLC.

Treatment patterns and outcomes among patients with small-cell lung cancer (SCLC) in Europe: a retrospective cohort study

OBJECTIVE

Describe characteristics, treatment patterns and clinical outcomes of patients with small-cell lung cancer (SCLC).

DESIGN

Retrospective chart review study defining several cohorts: (1) limited-stage disease (LD) SCLC initiating 1L therapy (1 L LD-SCLC), (2) extensive-stage disease (ED) SCLC initiating 1L therapy (1L ED-SCLC) and (3) patients initiating 2L therapy.

SETTING

39 physicians (medical oncologists, thoracic oncologists and/or pulmonologists) from France, Italy and the UK.

PARTICIPANTS

Patients >18 years of age with a confirmed diagnosis of LD-SCLC or ED-SCLC and a full oncology medical history. Patients included initiated a 1L (2013-2015) or 2L (2013-2016) treatment (chemotherapy and/or radiotherapy-RT).

PRIMARY AND SECONDARY OUTCOME MEASURES

Overall survival (OS) and progression-free survival (PFS).

RESULTS

231 patients in 1L LD-SCLC, 308 in 1L ED-SCLC and 225 with relapse/refractory SCLC initiating 2L treatment were included. The proportion of men was higher across all groups (56.8% to 68.5%) and mean age at time of diagnosis was 66.0 and 65.4 years in 1L LD-SCLC and 2L ED-SCLC cohorts. The majority of patients in LD-SCLC 1L group received chemotherapy with RT (76.2%). Patients initiating 2L therapy predominantly received chemotherapy alone (79.6%).Median OS in 1 L patients was 17.3 months in LD-SCLC and 8.8 months in ED-SCLC. Median PFS was 11.6 months in LD-SCLC and 6.1 months in ED-SCLC patients. Median OS in patients initiating 2L treatment was 6.6 months. OS from start of 2L treatment was lower in patients initially diagnosed with ED (5.1 months) than in patients initially diagnosed with LD (9.3 months) (p<0.0001). OS and PFS were assessed from the start of 1L or 2L therapy, depending on the cohort.

CONCLUSIONS

Despite the availability of a high number of treatments and combinations, the prognosis of SCLC is still unsatisfactory, especially for those patients diagnosed with ED-SCLC, indicating high unmet need in this patient population.

Adaptive radiation therapy (art) for patients with limited-stage small cell lung cancer (LS-SCLC): A dosimetric evaluation

Background

Adaptive radiation therapy (ART) refers to redesigning of radiation therapy (RT) treatment plans with respect to dynamic changes in tumor size and location throughout the treatment course. In this study, we performed a comparative volumetric and dosimetric analysis to investigate the impact of ART for patients with limited-stage small cell lung cancer (LS-SCLC).

Methods

Twenty-four patients with LS-SCLC receiving ART and concomitant chemotherapy were included in the study. ART was performed by replanning of patients based on a mid-treatment computed tomography (CT)-simulation which was routinely scheduled for all patients 20-25 days after the initial CT-simulation. While the first 15 RT fractions were planned using the initial CT-simulation images, the latter 15 RT fractions were planned using the mid-treatment CT-simulation images acquired 20-25 days after the initial CT-simulation. In order to document the impact of ART, target and critical organ dose-volume parameters acquired from this adaptive radiation treatment planning (RTP) were compared with the RTP based solely on the initial CT-simulation to deliver the whole RT dose of 60 Gy.

Results

Statistically significant reduction was detected in gross tumor volume (GTV) and planning target volume (PTV) during the conventionally fractionated RT course along with statistically significant reduction in critical organ doses with incorporation of ART.

Conclusion

One-third of the patients in our study who were otherwise ineligible for curative intent RT due to violation of critical organ dose constraints could be treated with full dose irradiation by use of ART. Our results suggest significant benefit of ART for patients with LS-SCLC.

Intracranial failure after hippocampal-avoidance prophylactic cranial irradiation in limited-stage small-cell lung cancer patients

We evaluated intracranial failure after hippocampus-avoidance-prophylactic cranial irradiation (HA-PCI) for limited-stage small-cell lung cancer (SCLC). Data of 106 patients who received PCI with 25 Gy were retrospectively reviewed. The patients were divided into two groups based on whether they underwent HA-PCI: the HA-PCI group (n = 48) and the conventional PCI (C-PCI) group (n = 58). Twenty-one patients experienced intracranial failure: 11 and 10 patients in the C-PCI and HA-PCI groups, respectively. Using the log-rank test, the intracranial failure rate was not significantly different between the groups (p = 0.215). No clinical factor was significantly associated with intracranial failure in multivariate Cox regression analysis, but HA-PCI tended to be associated with increased incidence of intracranial failure (HR 2.87, 95% CI 0.86–9.58, p = 0.087). Among patients who received HA-PCI, two developed peri-hippocampal recurrence. A higher thoracic radiotherapy dose (≥ 60 Gy) was significantly associated with DFS (HR 0.52, p = 0.048) and OS (HR 0.35, p = 0.003). However, HA-PCI was associated with neither DFS nor OS. Although HA-PCI may be associated with an increased risk of intracranial failure, HA-PCI did not impair disease control or survival. Future prospective randomized trials are needed to reach a definite conclusion.

Radiation Therapy for Small Cell Lung Cancer: An ASTRO Clinical Practice Guideline

PURPOSE

Several sentinel phase III randomized trials have recently been published challenging traditional radiation therapy (RT) practices for small cell lung cancer (SCLC). This American Society for Radiation Oncology guideline reviews the evidence for thoracic RT and prophylactic cranial irradiation (PCI) for both limited-stage (LS) and extensive-stage (ES) SCLC.

METHODS

The American Society for Radiation Oncology convened a task force to address 4 key questions focused on indications, dose fractionation, techniques and timing of thoracic RT for LS-SCLC, the role of stereotactic body radiation therapy (SBRT) compared with conventional RT in stage I or II node negative SCLC, PCI for LS-SCLC and ES-SCLC, and thoracic consolidation for ES-SCLC. Recommendations were based on a systematic literature review and created using a consensus-building methodology and system for grading evidence quality and recommendation strength.

RESULTS

The task force strongly recommends definitive thoracic RT administered once or twice daily early in the course of treatment for LS-SCLC. Adjuvant RT is conditionally recommended in surgically resected patients with positive margins or nodal metastases. Involved field RT delivered using conformal advanced treatment modalities to postchemotherapy volumes is also strongly recommended. For patients with stage I or II node negative disease, SBRT or conventional fractionation is strongly recommended, and chemotherapy should be delivered before or after SBRT. In LS-SCLC, PCI is strongly recommended for stage II or III patients who responded to chemoradiation, conditionally not recommended for stage I patients, and should be a shared decision for patients at higher risk of neurocognitive toxicities. In ES-SCLC, radiation oncologist consultation for consideration of PCI versus magnetic resonance surveillance is strongly recommended. Lastly, the use of thoracic RT is strongly recommended in select patients with ES-SCLC after chemotherapy treatment, including a conditional recommendation in those responding to chemotherapy and immunotherapy.

CONCLUSIONS

RT plays a vital role in both LS-SCLC and ES-SCLC. These guidelines inform best clinical practices for local therapy in SCLC.

High Biologically Effective Dose Radiotherapy for Brain Metastases May Improve Survival and Decrease Risk for Local Relapse Among Patients With Small-Cell Lung Cancer: A Propensity-Matching Analysis

To evaluate whether high biologically effective dose (BED) radiotherapy improves local control and survival outcomes for patients with brain metastases (BMs) from small-cell lung cancer (SCLC) and to determine possible prognostic factors. From January 1998 to June 2018, 250 patients with BM from SCLC were retrospectively analyzed. The Cutoff Finder program was used to classify patients by BED. Overall survival (OS) and BM progression-free survival (BM-PFS) were analyzed using the Kaplan-Meier method and log-rank test. A Cox regression model was used to calculate the hazard ratio and 95% CI for prognostic factors for OS among the study population and propensity score (PS)-matched patients. A BED of 47.4 was taken as the optimal cutoff value. Both OS and BM-PFS were significantly improved in the high-BED (>47.4 Gy) than in the low-BED (≤47.4 Gy) group (median OS: 17.5 months vs 9.5 months, P < .001, median BM-PFS: 14.4 months vs 8.3 months, P < .001). Biologically effective dose (P < .001), Eastern Cooperative Oncology Group performance status (P = .047), smoking (P = .005), and pleural effusion (P = .004) were independent prognostic factors for OS. Propensity score matching with a ratio of 1:2 resulted in 57 patients in the high-BED group and 106 patients in the low-BED group. In the PS-matched cohort, OS and BM-PFS were significantly prolonged in the high-BED group compared with the low-BED group (P < .001). Biologically effective dose >47.4 Gy improves survival among patients with BM from SCLC. Eastern Cooperative Oncology Group score, smoking, and pleural effusion independently affect OS of SCLC patients with BM.

Biologically effective dose (BED) escalation of stereotactic body radiotherapy (SBRT) for hepatocellular carcinoma patients (≤5 cm) with CyberKnife: protocol of study

BACKGROUND

There is a lack of data on the biologically effective dose and the efficacy of stereotactic body radiotherapy in hepatocellular carcinoma patients, and this study was conducted to explore the relation between BED and efficacy.

METHODS

This study is designed as a mono-center study. The participants are randomized into three group, and received the following recommended schedule: 49Gy/7f, 54Gy/6f and 55Gy/5f with BED₁₀ in correspondence to 83.3Gy, 102.6Gy and 115.5Gy. The primary outcome measures are to calculate local control rates (LC), overall survival rates (OS) and progression-free survival rates (PFS). The secondary outcome measures are to observe radiation-induced liver injury (RILD) rates, Child-Pugh score and indocyanine green retention rate at 15 min (ICG-R15) value before and after CK-SBRT. Moreover, gastrointestinal toxicities are also observed.

DISCUSSION

There is no uniform standard for CK-SBRT dose schedule of hepatocellular carcinoma. We propose to conduct a study determining the optimal CK-SBRT schedule of hepatocellular carcinoma patients (≤5 cm). The trial protocol has been approved by the Institutional Review Board of 302 Hospital of PLA (People's Liberation Army). The Ethics number is 2017111D.

TRAIL REGISTRATION

Clinical trails number: NCT03295500. Date of registration: November, 2017.

Treatment time to the end of thoracic radiotherapy has more predictive power for survival than radiation dose intensity in patients with limited-stage small-cell lung cancer receiving concurrent chemoradiation of more than 45 Gy

The optimal protocol for thoracic radiotherapy (TRT) in combination with chemotherapy in patients with limited-stage small-cell lung cancer (LS-SCLC) remains elusive. The present study aimed to evaluate radiation parameters in association with survival outcomes. A total of 101 patients with LS-SCLC who completed TRT at ≥45 Gy and concurrent chemotherapy were retrospectively reviewed. The median dose and duration of TRT were 50 Gy and 38 days, respectively. The median duration from the start of either therapy to the end of TRT (SER) was 60 days. The median survival for all patients was 26.9 months. The 3-year local control (LC), progression-free survival (PFS) and overall survival (OS) rates were 52.0, 29.5 and 37.6%, respectively, and the 5-year LC, PFS and OS rates were 50.1, 28.3 and 26.7%, respectively. Univariate analysis revealed that patient age, tumor stage, timing and dose of TRT, SER, prophylactic cranial irradiation (PCI), and tumor response were significantly associated with treatment outcomes. Multivariate analysis revealed that stage was the only significant prognostic factor for LC (P=0.011), PFS (P<0.001) and OS (P<0.001). Tumor response (P=0.014), PCI (P=0.007) and SER (P=0.005) were significant predictors of OS. OS was improved in patients who achieved complete response, and their SER was ≤70 days (P<0.001). Short treatment duration (SER ≤70 days) was a significant predictor of OS in patients with LS-SCLC who completed planned TRT at ≥45 Gy with concurrent chemoradiotherapy.

Timing of thoracic radiotherapy is more important than dose intensification in patients with limited-stage small cell lung cancer: a parallel comparison of two prospective studies

PURPOSE

The optimal radiotherapy dose/fraction for limited-stage small cell lung cancer (SCLC) is undefined. Our objectives were to compare efficacy between hyperfractionated thoracic radiotherapy (TRT; 1.5 Gy 2 times per day [bid] in 30 fractions) and hypofractionated TRT (2.5 Gy once per day [qd] in 22 fractions), and to explore prognostic factors influencing the prognosis, such as the timing of TRT.

METHODS

Patients enrolled in two independent prospective studies were combined and analyzed. The primary endpoint was local/regional control (LRC). The prognosis was analyzed using the Cox proportional hazards regression model.

RESULTS

Ninety-two and 96 patients were treated with hyperfractionated TRT and hypofractionated TRT, respectively. The 1‑ and 2‑year LRC rates of the two arms were 82.1 and 60.7%, and 84.9 and 68.8% (P = 0.27), respectively. The median overall survival (OS) times (months) were 28.3 (95% confidence interval, CI 16.4-40.1) and 22.0 (95% CI 16.4-27.5), while the 1‑year, 3‑year, and 5‑year OS rates were 85.2, 40.8, and 27.1%, and 76.9, 34.3, and 26.8% (P = 0.37), respectively. Using a multivariate Cox regression study, time (days) from the initiation of chemotherapy to TRT (TCT) ≤43 was associated with improved LRC (hazard radio, HR 0.39, 95% CI 0.20-0.76; P = 0.005). Time (days) from the start of chemotherapy to the end of TRT (SER) ≤63 (HR 0.50, 95% CI 0.32-0.80; P = 0.003) and prophylactic cranial irradiation (HR 0.43; 95% CI 0.29-0.63; P = 0.000) were favorably related to OS. Grade 2/3 acute radiation esophagitis was observed in 37.0 and 17.7% of patients in the hyperfractionated and hypofractionated arms, respectively (P = 0.003).

CONCLUSION

Both hyperfractionated and hypofractionated TRT schedules achieved good LRC and OS for patients with limited-stage SCLC in this study. Keeping TCT ≤43 and SER ≤63 resulted in a better prognosis. The incidence of acute esophagitis was significantly higher in the hyperfractionated arm.

Biologically effective dose (BED) of stereotactic body radiation therapy (SBRT) was an important factor of therapeutic efficacy in patients with hepatocellular carcinoma (≤5 cm)

BACKGROUND

To explore the association between biologically effective dose (BED) and survival rates in Child-Pugh A classification (CP-A) small hepatocellular carcinoma (HCC) patients treated with stereotactic body radiation therapy (SBRT).

METHODS

This retrospective study included 108 small HCC patients who were treated with SBRT between 2011 and 2014. The prescribed dose delivered to the tumor were 48Gy/8f, 49Gy/7f, 50Gy/5f and 54Gy/6f. The median biologically effective dose (BED10) of the total prescribed dose was 100Gy (76.8-102.6Gy). Factors associated with the survival rate were examined using the Cox proportion hazards model, and the factors associated with radiation-induced liver injury (RILD) were examined by logistic regression analysis.

RESULTS

For these patients, the median follow-up time was 42 months (6-77 months), and the 1-, 2- and 3-year overall survival (OS) rates were 96.3, 89.8 and 80.6%, respectively. The 1-, 2- and 3-year progression-free survival (PFS) rates were 85.2, 70.1 and 60.6%, respectively. The 1-, 2- and 3-year local control (LC) rates were 98.1, 96.2 and 95.1%, respectively. The 1-, 2- and 3-year distant metastasis- free survival (DMFS) rates were 86.1, 72.8 and 61.2%. The OS, PFS and DMFS were significantly higher in the BED10 ≥ 100Gy group than in the BED10 < 100Gy group (OS: p = 0.020; PFS: p = 0.017; DMFS: p = 0.012). The PLT count was a predictive factor of RILD.

CONCLUSIONS

SBRT is a safe and effective option for CP-A HCC patients. A BED10 value greater than 100Gy and lower CP score are associated with improved OS and PFS. Additionally, the peripheral PLT count are predictive factors of RILD.

Tumour size reduction after the first chemotherapy-course and outcomes of chemoradiotherapy in limited disease small-cell lung cancer

OBJECTIVES

Concurrent chemotherapy and thoracic radiotherapy (TRT) is recommended for limited disease small-cell lung cancer (LD SCLC). TRT should start as early as possible, often meaning with the second course due to patient referral time and the fact that TRT planning takes time. Early assessment of response to the first course of chemotherapy may be a useful way to individualise treatment. The aims of this study were to assess tumour size reduction after the first chemotherapy-course, and whether this reduction was associated with outcomes in LD SCLC.

MATERIAL AND METHODS

A randomised trial comparing twice-daily (45Gy/30 fractions) with once-daily (42Gy/15 fractions) TRT, given concurrently with four courses of cisplatin/etoposide (n=157) was the basis for this study. Tumour size was assessed on CT scans at baseline and planning scans for TRT according to RECIST 1.0.

RESULTS

CT scans were available for 135 patients (86%). Ninety-four percent had a reduction in tumour size after the first chemotherapy-course. The median reduction in sum of diameters (SOD) of measurable lesions was ÷16mm (÷84 to +10mm), corresponding to ÷18% (÷51 to +12%). Eighty-two percent had stable disease, 18% partial response. Reduction in SOD was significantly associated with complete response at first follow-up (OR: 1.05, 95% CI 1.01-1.09; p=0.013), PFS (HR: 0.97, 95% CI 0.96-0.99; p=0.001), and overall survival (HR: 0.98, 95% CI 0.96-1.00; p=0.010).

CONCLUSION

Response from the first course of chemotherapy had a significant positive association with outcomes from chemoradiotherapy, and might be used to stratify and randomise patients in future studies.