Impact of radiotherapy protocol adherence in NSCLC patients treated with concurrent chemoradiation: RTQA results of the PET-Plan trial

Clinical impact of radiotherapy quality assurance results in contemporary cancer trials: a systematic review and meta-analysis

BACKGROUND

Radiotherapy quality assurance (RTQA) is a critical aspect of randomized controlled trials (RCTs) and is associated with validity and reproducibility of the study findings. We conducted a systematic review and meta-analysis to assess the impact of RTQA results in contemporary RCTs on patient outcomes.

METHODS

We searched MEDLINE and CENTRAL from January 2010, to April 2024, for papers that report on the impact of RTQA on patient outcomes in contemporary RCTs. We conducted random-effects meta-analyses to examine the association of radiotherapy protocol deviations with overall survival (OS), progression free survival (PFS), and locoregional recurrence (LR).

RESULTS

Of 2,723 citations, 16 publications reporting on 13 RCTs were included across various disease sites. Of 7,170 total randomized patients across 1,076 institutions in over 25 countries, 5,560 patients had radiotherapy quality data and were included in RTQA analyses. Most included RCTs (7/12; 58 %) conducted exclusively retrospective RTQA after treatment completion. Our meta-analyses found that protocol deviations may be associated with worse OS [HR = 1.65 (95 % CI: 1.23-2.22; p < 0.001)] and PFS [HR = 1.79 (95 % CI: 1.00-3.21; p = 0.03)]. No significant association was demonstrated between protocol deviations and LR [HR = 2.09 (95 % CI: 0.85-5.15; p = 0.108)].

CONCLUSIONS

Quality of radiotherapy continues to have an important, measurable impact on patient outcomes in oncology RCTs, and rigorous, real-time RTQA procedures may diminish these effects by standardizing RT. Future trials should provide patient outcome data in relation to RTQA and continue to report on the effect of protocol deviations in the context of modern RT techniques.

Recommendations for radiotherapy quality assurance in clinical trials

Robust quality assurance (QA) of clinical trials in radiotherapy (RT) is paramount for minimising uncertainties in treatment delivery, thereby strengthening the statistical power of the study and increasing the likelihood of accurately answering the research question. As RT techniques evolve and become more complex, establishing an appropriate QA program for a specific clinical trial becomes increasingly challenging, highlighting the importance of clear and standardised recommendations. This study provide such recommendations for Principal Investigators (PIs) to consider when planning and conducting RT Quality Assurance (RTQA) for clinical trials. They arise from experiences with RTQA in the clinical trials conducted in the Danish Multidisciplinary Cancer Groups (DMCGs). The recommendations include a checklist to guide PIs in developing an effective RTQA program.

Design and pre-trial dose planning quality assurance of the Nordic trial of inhomogeneous dose escalated radiotherapy for patients with limited disease small cell lung cancer: NIELS

BACKGROUND AND PURPOSE

The NIELS trial will examine if inhomogeneous dose-escalated radiotherapy up to a mean dose of 80 Gy in 40 fractions (fx), twice-daily delivered (BID), for patients with limited disease small cell lung cancer can improve overall survival. Because of the inherent risks of dose-escalation, pre-trial QA is particularly important. This study aims to examine the feasibility of the NIELS trial planning approach in a multicenter setting.

MATERIALS AND METHODS

The NIELS trial will randomize patients between standard dose radiotherapy (60 Gy/40fx BID) and inhomogeneous dose-escalated radiotherapy (up to 80 Gy/40fx BID). Five representative patient cases were distributed to seven Nordic centers for pre-trial QA planning of a standard and an escalated dose plan. Targets for escalation were primary tumor (GTVp) and involved lymph nodes (GTVn). We evaluated inter-center variation in achievable dose-escalation and doses to organs at risk (OAR).

RESULTS

All targets could be escalated beyond the standard dose, with a median mean dose of 79.6 Gy [76.9-81.0] and 75.8 Gy [68.3-81.1] for GTVp and GTVn. Some targets could not be fully escalated due to OAR proximity. Three separate breaches of mandatory OAR constraints were observed in 35 escalated dose plans. There was a statistical difference in mean lung dose between standard and escalated plans, though clinically small, with a median inter-patient difference of 0.3 Gy. There were no differences in mean doses to the heart and esophagus.

CONCLUSION

Inhomogeneous dose-escalation as planned in the NIELS trial is feasible, and the dose-escalation can be performed respecting the OAR constraints in a multi-center setting.

Impact of estimated dose of radiation to immune cells (EDRIC) in locally advanced Non-Small-Cell lung Cancer: A secondary analysis of the multicenter randomized PET-Plan trial

PURPOSE

A higher estimated dose of radiation to immune cells (EDRIC) has been proposed as an explanation for failed attempts at thoracic radiation intensification as a part of concurrent chemoradiotherapy (cCRT) for locally advanced non-small-cell lung cancer (NSCLC), as lymphopenia in particular is a negative prognostic factor in this context. We studied the impact of EDRIC on survival in this secondary analysis of the prospective PET-Plan trial (ARO-2009-09; NCT00697333). Considering the immune system as an organ at risk for radiotherapy is of major importance in the current era of consolidation immunotherapy.

METHODS

Eligible patients had previously received chemoradiotherapy up to 60-74 Gy with radiation treatment planning based on an 18F-FDG PET/CT targeting all CT positive lymph nodes plus 50 Gy elective nodal irradiation (arm A) versus targeting only PET-positive nodes (arm B). EDRIC was calculated with the original model by Jin et al. in addition to a modified score with cohort-specific weight parameters.

RESULTS

Sufficient data were available in 153 patients with a median follow-up time (95 % confidence interval [CI]) of 41.6 (34.6 - 53.7) months. Using the original model, the mean EDRIC (range) was 5.70 (3.23 - 8.44) Gy and showed a strong inverse correlation with PFS (hazard ratio [HR] = 1.77; 95 % CI 1.23-2.54; p = 0.002) and OS (HR = 1.72; 95 % CI 1.12-2.65; p = 0.01). The mean modified EDRIC (range) was 5.30 (3.01 - 8.38) Gy, again with a strong inverse correlation with PFS (HR = 1.66; 95 % CI 1.16-2.38; p = 0.006) but not OS (HR = 1.40; 95 % CI 0.91-2.15; p = 0.122). Neither radiation treatment allocation (arm A vs. B) nor technique (3D-CRT vs. IMRT) influenced EDRIC (p = 0.889 and p = 0.958, respectively) and EDRIC did not influence the rate of early or delayed hematological toxicity. On multivariate analysis, mean body dose (MBD) was the main contributing factor of the EDRIC equation to PFS and OS.

CONCLUSION

Higher doses of radiation to the immune system were associated with worse PFS in this secondary analysis of the PET-Plan trial. The omission of elective nodal irradiation did not influence EDRIC. MBD could potentially suffice as a surrogate for EDRIC, as it is more readily available and requires fewer calculations. Future trials should aim to refine existing models and investigate ways to reduce EDRIC to limit its effects in patients undergoing cCRT for locally advanced NSCLC.

Impact of mediastinal tumor burden and lymphatic spread in locally advanced non-small-cell lung cancer: A secondary analysis of the multicenter randomized PET-Plan trial

PURPOSE

The aim of this secondary analysis of the prospective randomized phase 2 PET-Plan trial (ARO-2009-09; NCT00697333) was to evaluate the impact of mediastinal tumor burden and lymphatic spread in patients with locally advanced non-small-cell lung cancer (NSCLC).

METHODS

All patients treated per protocol (n = 172) were included. Patients received isotoxically dose-escalated chemoradiotherapy up to a total dose of 60-74 Gy in 30-37 fractions, aiming as high as possible while adhering to normal tissue constraints. Radiation treatment (RT) planning was based on an 18F-FDG PET/CT targeting all lymph node (LN) stations containing CT positive LNs (i.e. short axis diameter > 10 mm), even if PET-negative (arm A) or targeting only LN stations containing PET-positive nodes (arm B). LN stations were classified into echelon 1 (ipsilateral hilum), 2 (ipsilateral station 4 and 7), and 3 (rest of the mediastinum, contralateral hilum). The endpoints were overall survival (OS), progression-free survival (PFS), and freedom from local progression (FFLP).

RESULTS

The median follow-up time (95 % confidence interval [CI]) was 41.1 (33.8 - 50.4) months. Patients with a high absolute number of PET-positive LN stations had worse OS (hazard ratio [HR] = 1.09; 95 % CI 0.99 - 1.18; p = 0.05) and PFS (HR = 1.12; 95 % CI 1.04 - 1.20; p = 0.003), irrespective of treatment arm allocation. The prescribed RT dose to the LNs did not correlate with any of the endpoints when considering all patients. However, in patients in arm B (i.e., PET-based selective nodal irradiation), prescribed RT dose to each LN station correlated significantly with FFLP (HR=0.45; 95 % CI 0.24-0.85; p = 0.01). Furthermore, patients with involvement of echelon 3 LN stations had worse PFS (HR = 2.22; 95 % CI 1.16-4.28; p = 0.02), also irrespective of allocation.

CONCLUSION

Mediastinal tumor burden and lymphatic involvement patterns influence outcome in patients treated with definitive chemoradiotherapy for locally advanced NSCLC. Higher dose to LNs did not improve OS, but did improve FFLP in patients treated with PET-based dose-escalated RT.

Radiotherapy trial quality assurance processes: a systematic review

Quality assurance remains a neglected component of many trials, particularly for technical interventions, such as surgery and radiotherapy, for which quality of treatment is an important component in defining outcomes. We aimed to evaluate evidence for the processes used in radiotherapy quality assurance of clinical trials. A systematic review was undertaken focusing on use of a pre-trial outlining benchmark case and subsequent on-trial individual case reviews of outlining for recruited patients. These pre-trial and on-trial checks are used to ensure consistency and standardisation of treatment for each patient recruited to the trial by confirming protocol compliance. Non-adherence to the trial protocol has been shown to have a negative effect on trial outcomes. 29 studies published between January, 2000, and December, 2022, were identified that reported on either outlining benchmark case results or outlining individual case review results, or both. The trials identified varied in their use of radiotherapy quality assurance practices and reporting of outcomes was inconsistent. Deviations from trial protocols were frequent, particularly regarding outlining. Studies correlating benchmark case results with on-trial individual case reviews provided mixed results, meaning firm conclusions could not be drawn regarding the influence of the pre-trial benchmark case on subsequent on-trial performance. The optimal radiotherapy quality assurance processes were unclear, and there was little evidence available. Improved reporting of outcomes from radiotherapy quality assurance programmes is needed to develop an evidence base for the optimal approach to radiotherapy quality assurance in trials.

Association between radiotherapy protocol variations and outcome in the CONVERT trial

Background

Radiotherapy quality assurance (QA) is integral to radiotherapy delivery. Here we report comprehensive contouring, dosimetry, and treatment delivery QA, describe protocol compliance, and detail the impact of protocol variations on acute grade ≥3 toxicity, progression free survival (PFS), and overall survival (OS) in the phase III CONVERT trial.

Materials/Methods

Radiotherapy planning data from one hundred randomly selected patients were requested. Members of the CONVERT Trial Management Group (TMG) recontoured the heart, lung, and spinal cord organs at risk (OAR) according to the trial guideline. The existing radiotherapy plan were re-applied to the new structures and the new dosimetric data were recollected. Compliance with radiotherapy QA components were recorded and radiotherapy QA components were pooled into protocol variations: acceptable, acceptable variation, and unacceptable variation. Univariable analysis with a Cox proportional hazards model established the relationship between protocol variations and patient outcome.

Results

Ninety-three cases were submitted for retrospective radiotherapy QA review. Demographics of the radiotherapy QA cohort (n=93) matched the non-QA (n=450) cohort. 97.8% of gross tumour volume (GTV) contours were protocol compliant. OAR contours were non-compliant in 79.6% instances of the heart, 37.6% lung, and 75.3% spinal cord. Of the non-compliant heart contours, 86.5% and 2.7% had contours caudal and cranial to the protocol-defined heart borders. 10.8% did not include the pericardial sac and 2.7% did not include the anterior aspect of the pericardium. Eleven (11.8%) submissions exceeded protocol-defined dosimetric heart constraints; six of which were only noted on the application of protocol-compliant contours. Unacceptable variations were not associated with an increase in grade 3 toxicity (p=0.808), PFS (p=0.232), or OS (p=0.743).

Conclusion

Non-protocol compliant heart contours were associated with increased dose delivered to the heart OAR, with 11.8 % of submitted heart structures exceeding protocol-defined constraints. In this QA cohort of patients with small cell lung cancer, unacceptable variations were not associated with acute grade ≥3 toxicity, PFS, or OS. Radiotherapy QA remains the cornerstone of high-quality radiotherapy delivery and should be embedded into clinical trial and non-clinical trial practice; clinical trials should report standardised radiotherapy QA parameters alongside trial outcomes.

Radiotherapy Quality Assurance in the PORTEC-3 (TROG 08.04) Trial

AIMS

Quality assurance in radiotherapy (QART) is essential to ensure the scientific integrity of a clinical trial. This paper reports the findings of the retrospective QART assessment for all centres that participated in PORTEC-3; a randomised controlled trial that compared pelvic radiotherapy with concurrent chemoradiotherapy to the pelvis followed by adjuvant chemotherapy. The trial showed an overall survival benefit for the addition of the chemotherapy in the management of women with high-risk endometrial cancer.

MATERIALS AND METHODS

Clinicians were invited to upload a randomly selected case/s treated at each of the participating sites. Panel reviewers analysed the contours to certify that the target volumes and organ at risk structures were contoured according to guidelines. The results were categorised into acceptable, minor variation, major variation or unevaluable. The radiotherapy plans were dosimetrically evaluated using the well-established Trans-Tasman Radiation Oncology Group (TROG) protocol.

RESULTS

Between August 2010 and January 2018, data from 146 patients of 686 consecutively treated patients were retrospectively reviewed. All 16 Australia and New Zealand and 71 of 77 international centres uploaded data for evaluation. In total, 3514 dosimetric and contour variables were reviewed. Of these, 3136 variables were deemed acceptable (89.2%), with 335 minor (9.6%) and 43 major variations (1.2%). Major contour variations included the clinical target volume vaginal vault, clinical target volume parametria and differential planning target volume vault expansion.

CONCLUSION

The results of the QART assessment confirmed high uniformity and low rates of both minor and major deviations in contouring and dosimetry in all sites. This supports the safe introduction of the PORTEC-3 treatment protocol into routine clinical practice.

MiR-145 modulates the radiosensitivity of non-small cell lung cancer cells by suppression of TMOD3

Radioresistance is a major problem encountered in the treatment of non-small cell lung cancer (NSCLC). Aberrant microRNA (miRNA) expression contributes to multiple cancer‑associated signaling pathways, and profoundly influences effects of radiotherapy (RT) in cancers. MicroRNA-145-5p (miR-145) is recognized as a tumor suppresser in NSCLC. However, the roles of miR-145 during radiotherapy of NSCLC are largely unknown. The present study aimed to investigate the function and underlying mechanism of miR-145 in modulation of radiosensitivity in NSCLC. We generated radioresistant H460 and A549 subclones, named H460R and A549R, respectively, and found that irradiation (IR) could suppress the expression levels of miR-145 in radioresistant NSCLC cells. Furthermore, overexpression of miR-145 could sensitize radioresistant NSCLC cells to IR, while knockdown of miR-145 in NSCLC cells acted the converse manner. Mechanically, miR-145 was able to directly target 3'UTR of tropomodulin 3 (TMOD3) mRNA and decrease the expression of TMOD3 at the levels of mRNA and protein. Additionally, we confirmed that miR-145 could enhance the radiosensitivity of radioresistant NSCLC cells by targeting TMOD3 in vitro and in vivo, and could be used as a target in clinical treatment of NSCLC. Collectively, restoration of miR-145 expression increases the radiosensitivity of radioresistant NSCLC cells by suppression of TMOD3, and miR-145 can act as a new radiosensitizer for NSCLC therapy.