Stereotactic Conformal Radiotherapy in Non-small Cell Lung Cancer — An Overview

Ablative radiosurgery for cardiac arrhythmias - A systematic review

Stereotactic body radiotherapy (SBRT) is a high precision technique that is commonly used for malignant lesions in lung, liver, pancreas and spine. Recent reports suggest promise in use of SBRT as a tool in atrial and ventricular cardiac arrhythmias. The present systematic review deals with the use of SBRT technology for this novel indication. A PubMed search was done for articles published between 1990 and 2020. All original articles, case reports, case series of treated patients were included in the analyses. Out of the 55 articles in PubMed search, our search found 1 phase I/II clinical case series, 3 clinical case reports, 3 animal studies and 4 dosimetric studies related to cardiac SBRT for arrythmias. All studies used a uniform cardiac dose of 25Gy. The available preclinical, dosimetric and clinical studies have suggested that SBRT for cardiac arrhythmias could become a potential alternative in suitable patients. Cardiac and radiation oncology community await further data and experience in this modality, including safety and outcomes.

Metabolic positron emission tomography parameters predict failure patterns in early non-small-cell lung cancer treated with stereotactic body radiation therapy: a single institution experience

Objective

The prognostic value of metabolic parameters using 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) has not been established for early non-small cell lung cancer (NSCLC). Accordingly, the authors investigated the prognostic value of metabolic parameters in terms of failure patterns in patients with early NSCLC who underwent stereotactic body radiation therapy (SBRT).

Methods

Data from 35 patients with Stage I NSCLC who underwent SBRT using CyberKnife and received pretreatment FDG PET/CT between 2008 and 2016 were retrospectively reviewed. Maximum standardized uptake value (SUVmax), metabolic tumor volume, and total lesion glycolysis were measured. The significance of these parameters with regard to failure patterns was assessed.

Results

The median follow-up was 23 months for all patients and 34 months for living patients. Ten patients experienced recurrence: three local failures, five regional failures (RF), and eight distant failures (DF). Three-year local, regional and distant control rates were 96.7%, 86.4% and 71.1%, respectively. High SUVmax (<9 vs. ≥9) was an independent predictive factor associated with increased RF (P = 0.027) and DF (P = 0.008). Furthermore, SUVmax was indicative of both progression-free (P = 0.015) and overall (P = 0.034) survival.

Conclusions

High SUVmax was a significant metabolic parameter associated with increased RF and DF in patients with early NSCLC who received SBRT, having a high propensity for dissemination. These results suggest that adjuvant treatment in conjunction with SBRT may be considered in patients with early NSCLC and high SUVmax.

Continuous Hyperfractionated Accelerated Radiotherapy (CHART) for Non-small Cell Lung Cancer (NSCLC): 7 Years' Experience From Nine UK Centres

AIM

Continuous hyperfractionated accelerated radiotherapy (CHART) remains an option to treat non-small cell lung cancer (NSCLC; NICE, 2011). We have previously published treatment outcomes from 1998-2003 across five UK centres. Here we update the UK CHART experience, reporting outcomes and toxicities for patients treated between 2003 and 2009.

MATERIALS AND METHODS

UK CHART centres were invited to participate in a retrospective data analysis of NSCLC patients treated with CHART from 2003 to 2009. Nine (of 14) centres were able to submit their data into a standard database. The Kaplan-Meier method estimated survival and the Log-rank test analysed the significance.

RESULTS

In total, 849 patients had CHART treatment, with a median age of 71 years (range 31-91), 534 (63%) were men, 55% had undergone positron emission tomography-computed tomography (PET-CT) and 26% had prior chemotherapy; 839 (99%) patients received all the prescribed treatment. The median overall survival was 22 months with 2 and 3 year survival of 47% and 32%, respectively. Statistically significant differences in survival were noted for stage IA versus IB (33.2 months versus 25 months; P = 0.032) and IIIA versus IIIB (20 months versus 16 months; P = 0.018). Response at 3 months and outcomes were significantly linked; complete response showing survival of 34 months against 19 months, 15 months and 8 months for partial response, stable and progressive disease, respectively (P < 0.001). Age, gender, performance status, prior chemotherapy and PET-CT did not affect the survival outcomes. Treatment was well tolerated with <5% reporting ≥grade 3 toxicity.

CONCLUSION

In routine practice, CHART results for NSCLC remain encouraging and we have been able to show an improvement in survival compared with the original trial cohort. We have confirmed that CHART remains deliverable with low toxicity rates and we are taking a dose-escalated CHART regimen forward in a randomised phase II study of sequential chemoradiotherapy against other accelerated dose-escalated schedules.

Continuous hyperfractionated accelerated radiotherapy - Escalated dose (CHART-ED): A phase I study

INTRODUCTION

Patients who present with locally advanced inoperable non-small cell lung cancer (NSCLC) may be suitable for radical radiotherapy. A randomised trial of 563 patients compared CHART and conventional radical radiotherapy (60 Gy/30f) given over 6 weeks and suggested that CHART resulted in a 9% improvement in 2-year survival (Saunders et al., 1999). RT dose escalation for both conventional and CHARTWEL (CHART-WeekEndLess) - fractionation schedules is feasible with modern 3-dimensional CT-based planning techniques and we initiated a phase I CHART dose escalation study in 2009.

METHODS

Patients with WHO performance status 0-2 histologically confirmed, inoperable, stage I-III non-small cell lung cancer were recruited into an open phase I dose escalation trial. Three cohorts of six patients were recruited sequentially. Total dose was escalated from standard CHART radiotherapy of 54 Gy/36f/12 days to 57.6G y (2 × 1.8 Gy fractions on day 15, Group 1), 61.2 Gy (4 × 1.8 Gy fractions on days 15-16, Group 2) and 64.8 Gy (6 × 1.8 Gy fractions on days 15-17, Group 3).

RESULTS

Between April 2010 and May 2012, 18 patients were enrolled from 5 UK centres and received escalated dose radiotherapy. 14 were male, 16 squamous cell histology and 12 were stage IIIA or IIIB. The median age was 70 years and baseline characteristics were similar across the three dose cohorts. One patient did not start escalated radiotherapy but all remaining patients completed their planned radiotherapy schedules. Of these 9 patients have died to date with a median survival of 2 years across the three cohorts. Grade 3 or 4 adverse events (fatigue, dysphagia, nausea and anorexia - classified according to the National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE) version 4.0) were reported in 6 patients but the pre-specified dose limiting toxicities (grade 4 early oesophagitis; grade 3 cardiac, spinal cord and pneumonitis) were not observed.

CONCLUSIONS

CHART remains a radiotherapy schedule in routine use across the UK and in this dose escalation study no dose limiting toxicities were observed. We feel the dose of 64.8 Gy/42f/17 days should be taken forward into further clinical trials. The sample size used in this study was small so we plan a randomised phase II study that includes other radiotherapy schedules to confirm safety and select an accelerated sequential chemo-radiotherapy schedule to take into phase III studies.

Optimizing the flattening filter free beam selection in RapidArc®-based stereotactic body radiotherapy for Stage I lung cancer

OBJECTIVE

To optimize the flattening filter-free (FFF) beam selection in stereotactic body radiotherapy (SBRT) treatment for Stage I lung cancer in different fraction schemes.

METHODS

Treatment plans from 12 patients suffering from Stage I lung cancer were designed using the 6XFFF and 10XFFF beams in different fraction schemes of 4 × 12, 3 × 18 and 1 × 34 Gy. Plans were evaluated mainly in terms of organs at risk (OARs) sparing, normal tissue complication probability (NTCP) estimation and treatment efficiency.

RESULTS

Compared with the 10XFFF beam, 6XFFF beam showed statistically significant lower dose to all the OARs investigated. The percentage of NTCP reduction for both lung and chest wall was about 10% in the fraction schemes of 4 × 12 and 3 × 18 Gy, whereas only 7.4% and 2.6% was obtained in the 1 × 34 Gy scheme. For oesophagus, heart and spinal cord, the reduction was greater with the 6XFFF beam, but their absolute estimates were <10(-6)%. The mean beam-on time for 6XFFF and 10XFFF beams at 4 × 12, 3 × 18 and 1 × 34 Gy schemes were 2.2 ± 0.2 vs 1.5 ± 0.1, 3.3 ± 0.9 vs 2.0 ± 0.5 and 6.3 ± 0.9 vs 3.5 ± 0.4 min, respectively.

CONCLUSION

The 6XFFF beam obtains better OARs sparing and lower incidence of NTCP in SBRT treatment of Stage I lung cancer, whereas the 10XFFF beam improves the treatment efficiency. To balance the OARs sparing and intrafractional variation owing to the prolonged treatment time, the authors recommend using the 6XFFF beam in the 4 × 12 and 3 × 18 Gy schemes but the 10XFFF beam in the 1 × 34 Gy scheme.

ADVANCES IN KNOWLEDGE

This study optimizes the FFF beam selection in different fraction schemes in SBRT treatment of Stage I lung cancer.

Effect of stereotactic dosimetric end points on overall survival for Stage I non-small cell lung cancer: a critical review

Stereotactic body radiation therapy (SBRT) delivers a high biologically effective dose while minimizing toxicities to surrounding tissues. Within the scope of clinical trials and local practice, there are inconsistencies in dosimetrics used to evaluate plan quality. The purpose of this critical review was to determine if dosimetric parameters used in SBRT plans have an effect on local control (LC), overall survival (OS), and toxicities. A database of relevant trials investigating SBRT for patients with early-stage non-small cell lung cancer was compiled, and a table of dosimetric variables used was created. These parameters were compared and contrasted for LC, OS, and toxicities. Dosimetric end points appear to have no effect on OS or LC. Incidences of rib fractures correlate with a lack of dose-volume constraints (DVCs) reported. This review highlights the great disparity present in clinical trials reporting dosimetrics, DVCs, and toxicities for lung SBRT. Further evidence is required before standard DVCs guidelines can be introduced. Dosimetric end points specific to stereotactic treatment planning have been proposed but require further investigation before clinical implementation.

Accelerated hypo-fractionated radiotherapy for non small cell lung cancer: results from 4 UK centres

BACKGROUND AND PURPOSE

A variety of radiotherapy fractionations are used as potentially curative treatments for non-small cell lung cancer. In the UK, 55 Gy in 20 fractions over 4 weeks (55/20) is the most commonly used fractionation schedule, though it has not been validated in randomized phase III trials. This audit pooled together existing data from 4 UK centres to produce the largest published series for this schedule.

MATERIALS AND METHODS

4 UK centres contributed data (Cambridge, Cardiff, Glasgow and Sheffield). Case notes and radiotherapy records of radically treated patients between 1999 and 2007 were retrospectively reviewed. Basic patient demographics, tumour characteristics, radiotherapy and survival data were collected and analysed.

RESULTS

609 patients were identified of whom 98% received the prescribed dose of 55/20. The median age was 71.3 years, 62% were male. 90% had histologically confirmed NSCLC, 49% had stage I disease. 27% had received chemotherapy (concurrent or sequential) with their radiotherapy. The median overall survival from time of diagnosis was 24.0 months and 2 year overall survival was 50%.

CONCLUSION

These data show respectable results for patients treated with accelerated hypo-fractionated radiotherapy for NSCLC with outcomes comparable to those reported for similar schedules and represent the largest published series to date for 55/20 regime.

Combined radio- and chemotherapy for non-small cell lung cancer: systematic review of landmark studies based on acquired citations

The important role of combined chemoradiation for several groups of patients with non-small cell lung cancer (NSCLC) is reflected by the large number of scientific articles published during the last 30 years. Different measures of impact and clinical relevance of published research are available, each with its own pros and cons. For this review, article citation rate was chosen. Highly cited articles were identified through systematic search of the citation database Scopus. Among the 100 most often cited articles, meta-analyses (n = 5) achieved a median of 203 citations, guidelines (n = 7) 97, phase III trials (n = 29) 168, phase II trials (n = 21) 135, phase I trials (n = 7) 88, and others combined 115.5 (p = 0.001). Numerous national and international cooperative groups and several single institutions were actively involved in performing often cited, high-impact trials, reflecting the fact that NSCLC is a world-wide challenge that requires research collaboration. Platinum-containing combinations have evolved into a standard of care, typically administered concurrently. The issue of radiotherapy fractionation and total dose has also been studied extensively, yet with less conclusive results. Differences in target volume definition have been addressed. However, it was not possible to test all theoretically possible combinations of radiotherapy regimens, drugs, and drug doses (lower radiosensitizing doses compared to higher systemically active doses). That is why current guidelines offer physicians a choice of different, presumably equivalent treatment alternatives. This review identifies open questions and strategies for further research.