Outcomes of Routine Intensity Modulated Radiation Therapy Quality Assurance in a Large Head and Neck Cancer Center

A systematic review and meta-analysis on the impact of institutional peer review in radiation oncology

BACKGROUND

Radiotherapy peer review is recognized as a key component of institutional quality assurance, though the impact is ill-defined. We conducted the first systematic review and meta-analysis to date to quantify the impact of institutional peer review on the treatment planning workflow including radiotherapy contours, prescription and dosimetry.

METHODS

We searched several medical and healthcare databases from January 1, 2000, to May 25, 2024, for papers that report on the impact of institutional radiotherapy peer review on treatment plans. We conducted random-effects meta-analyses of proportions to summarize the rates of any change recommendation and major change recommendation (suggesting re-planning or re-simulation due to safety concerns) following peer review processes. To explore differences in change recommendations dependent on location, radiotherapy intent, technique, and peer review structure characteristics, we conducted analyses of variance.

RESULTS

Of 9,487 citations, we identified 55 studies that report on 96,444 case audits in 10 countries across various disease sites. The pooled proportion of any change recommendation was 28 % (95 %CI = 21-35) and major change recommendation was 12 % (95 %CI = 7-18). Proportions of change recommendation were not impacted by any treatment characteristics. The most common reasons for change recommendation include target volume delineation (25/55; 45 %), target dose prescription (18/55; 33 %), organ at risk dose prescription (5/55; 9 %), and organ at risk volume delineation (3/55; 5 %).

CONCLUSIONS

Our review provides evidence that peer review results in treatment plan change recommendations in over one in four patients. The results suggest that some form of real-time, early peer review may be beneficial for all cases, irrespective of treatment intent or RT technique.

Latin American Consensus on the Treatment of Head and Neck Cancer

Head and neck squamous cell carcinoma (HNSCC) is well known as a serious health problem worldwide, especially in low-income countries or those with limited resources, such as most countries in Latin America. International guidelines cannot always be applied to a population from a large region with specific conditions. This study established a Latin American guideline for care of patients with head and neck cancer and presented evidence of HNSCC management considering availability and oncologic benefit. A panel composed of 41 head and neck cancer experts systematically worked according to a modified Delphi process on (1) document compilation of evidence-based answers to different questions contextualized by resource availability and oncologic benefit regarding Latin America (region of limited resources and/or without access to all necessary health care system infrastructure), (2) revision of the answers and the classification of levels of evidence and degrees of recommendations of all recommendations, (3) validation of the consensus through two rounds of online surveys, and (4) manuscript composition. The consensus consists of 12 sections: Head and neck cancer staging, Histopathologic evaluation of head and neck cancer, Head and neck surgery-oral cavity, Clinical oncology-oral cavity, Head and neck surgery-oropharynx, Clinical oncology-oropharynx, Head and neck surgery-larynx, Head and neck surgery-larynx/hypopharynx, Clinical oncology-larynx/hypopharynx, Clinical oncology-recurrent and metastatic head and neck cancer, Head and neck surgery-reconstruction and rehabilitation, and Radiation therapy. The present consensus established 48 recommendations on HNSCC patient care considering the availability of resources and focusing on oncologic benefit. These recommendations could also be used to formulate strategies in other regions like Latin America countries.

Radiotherapy quality assurance in the TROG 12.01 randomised trial and its impact on loco-regional failure

Introduction

There is no consensus as to what specifically constitutes head and neck cancer radiotherapy quality assurance (HNC RT QA). The aims of this study are to (1) describe the RT QA processes used in the TROG 12.01 study, (2) review the RT QA processes undertaken for all patients with loco-regional failure (LRF), and (3) provide prospective data to propose a consensus statement regarding the minimal components and optimal timing of HNC RT QA.

Materials and methods

All patients undergoing RT QA in the original TROG 12.01 study were included in this substudy. All participating sites completed IMRT credentialling and a clinical benchmark case. Real-time (pre-treatment) RT QA was performed for the first patient of each treating radiation oncologist, and for one in five of subsequent patients. Protocol violations were deemed major if they related to contour and/or dose of gross tumour volume (GTV), high dose planning target volume (PTVhd), or critical organs of risk (spinal cord, mandible, and brachial plexus).

Results

Thirty HNROs from 15 institutions accrued 182 patients. There were 28 clinical benchmark cases, 27 pre-treatment RT QA cases, and 38 post-treatment cases. Comprehensive RT QA was performed in 65/182 (36%) treated patients. Major protocol violations were found in 5/28 benchmark cases, 5/27 pre-treatment cases, and 6/38 post-treatment cases. An independent review of all nine LRF cases showed major protocol violations in four of nine cases.

Conclusion

Only pre-treatment RT QA can improve patient outcomes. The minimal components of RT QA in HNC are GTVs, PTVhd, and critical organs at risk. What constitutes major dosimetric violations needs to be harmonised.

Toward real-time automatic treatment planning (RTTP) with a one-step 3D fluence map prediction method and (nonorthogonal) convolution technique

PURPOSE

To establish and evaluate a (quasi) real-time automated treatment planning (RTTP) strategy utilizing a one-step full 3D fluence map prediction model based on a nonorthogonal convolution operation for rectal cancer radiotherapy.

METHODS

The RTTP approach directly extracts 3D projections from volumetric CT and anatomical data according to the beam incident direction. A 3D deep learning model with a nonorthogonal convolution operation was established that takes projections in cone beam space as input, extracts the features along and around the ray-trace path, and outputs a predicted fluence map (PFM) for each beam. The PFM is then converted to the MLC sequence with deliverable MUs to generate the final treatment plan. A total of 314 rectal adenocarcinoma patients with 2198 projection data samples were used in model training and validation. An extra 20 patients were used to test the feasibility of the RTTP method by comparing the plan quality, efficiency, deliverability performance, and physician blinded review results with the manual plans.

RESULTS

Overall, the RTTP plans met the clinical dose criteria for target coverage, conformity, homogeneity, and organ-at-risk dose sparing. Compared to manual plans, the RTTP plans showed increases in PTV D_1% by only 2.33% (p < 0.001) and a decrease in PTV D_99% by 0.45% (p < 0.05). The RTTP plans showed a dose increase in the bladder, with a V₅₀ of 14.01 ± 11.75% vs. 10.74 ± 8.51%, respectively, and no significant increases in the femoral head with the mean dose. The planning efficiency was improved in RTTP planning, with 39 s vs. 944 s in fluence map generation; the deliverability performance was saved by 1.91% (p < 0.001) in total MU. According to the blinded plan review by our physician, 55% of RTTP plans can be directly used in clinical radiotherapy treatment.

CONCLUSION

The quasi RTTP method improves the planning efficiency and deliverability performance while maintaining a plan quality close to that of the optimized manual plans in rectal radiotherapy.

Head and neck radiotherapy quality assurance conference for dedicated review of delineated targets and organs at risk: results of a prospective study

Purpose

Head and neck (HN) radiotherapy (RT) is complex, involving multiple target and organ at risk (OAR) structures delineated by the radiation oncologist. Site-agnostic peer review after RT plan completion is often inadequate for thorough review of these structures. In-depth review of RT contours is critical to maintain high-quality RT and optimal patient outcomes.

Materials and Methods

In August 2020, the HN RT Quality Assurance Conference, a weekly teleconference that included at least one radiation oncology HN specialist, was activated at our institution. Targets and OARs were reviewed in detail prior to RT plan creation. A parallel implementation study recorded patient factors and outcomes of these reviews. A major change was any modification to the high-dose planning target volume (PTV) or the prescription dose/fractionation; a minor change was modification to the intermediate-dose PTV, low-dose PTV, or any OAR. We analysed the results of consecutive RT contour review in the first 20 months since its initiation.

Results

A total of 208 patients treated by 8 providers were reviewed: 86·5% from the primary tertiary care hospital and 13·5% from regional practices. A major change was recommended in 14·4% and implemented in 25 of 30 cases (83·3%). A minor change was recommended in 17·3% and implemented in 32 of 36 cases (88·9%). A survey of participants found that all (n = 11) strongly agreed or agreed that the conference was useful.

Conclusion

Dedicated review of RT targets/OARs with a HN subspecialist is associated with substantial rates of suggested and implemented modifications to the contours.

Disadvantaged Subgroups Within the Global Head and Neck Cancer Population: How Can We Optimize Care?

Within the global head and neck cancer population, there are subgroups of patients with poorer cancer outcomes independent from tumor characteristics. In this article, we review three such groups. The first group comprises patients with nasopharyngeal cancer in low- and middle-income countries where access to high-volume, well-resourced radiotherapy centers is limited. We discuss a recent study that is aiming to improve outcomes through the instigation of a comprehensive radiotherapy quality assurance program. The second group comprises patients with low socioeconomic status in a high-income country who experience substantial financial toxicity, defined as financial hardship for patients due to health care costs. We review causes and consequences of financial toxicity and discuss how it can be mitigated. The third group comprises older patients who may poorly tolerate and not benefit from intensive standard-of-care treatment. We discuss the role of geriatric assessment, particularly in relation to the use of chemotherapy. Through better recognition and understanding of disadvantaged groups within the global head and neck cancer population, we will be better placed to instigate the necessary changes to improve outcomes and quality of life for patients with head and neck cancer.

The quantitative impact of joint peer review with a specialist radiologist in head and neck cancer radiotherapy planning

OBJECTIVES

Radiologist input in peer review of head and neck radiotherapy has been introduced as a routine departmental approach. The aim was to evaluate this practice and to quantitatively analyse the changes made.

METHODS

Patients treated with radical-dose radiotherapy between August and November 2020 were reviewed. The incidence of major and minor changes, as defined by The Royal College of Radiologists guidance, was prospectively recorded. The amended radiotherapy volumes were compared with the original volumes using Jaccard Index (JI) to assess conformity; Geographical Miss Index (GMI) for undercontouring; and Hausdorff Distance (HD) between the volumes.

RESULTS

In total, 73 out of 87 (84%) patients were discussed. Changes were recommended in 38 (52%) patients: 30 had ≥1 major change, eight had minor changes only. There were 99 amended volumes: The overall median JI, GMI and HD was 0.91 (interquartile range [IQR]=0.80-0.97), 0.06 (IQR = 0.02-0.18) and 0.42 cm (IQR = 0.20-1.17 cm), respectively. The nodal gross-tumour-volume (GTVn) and therapeutic high-dose nodal clinical-target-volume (CTVn) had the biggest magnitude of changes: The median JI, GMI and HD of GTVn was 0.89 (IQR = 0.44-0.95), 0.11 (IQR = 0.05-0.51), 3.71 cm (IQR = 0.31-6.93 cm); high-dose CTVn was 0.78 (IQR = 0.59-0.90), 0.20 (IQR = 0.07-0.31) and 3.28 cm (IQR = 1.22-6.18 cm), respectively. There was no observed difference in the quantitative indices of the 85 'major' and 14 'minor' volumes (p = 0.5).

CONCLUSIONS

Routine head and neck radiologist input in radiotherapy peer review is feasible and can help avoid gross error in contouring.

ADVANCES IN KNOWLEDGE

The major and minor classifications may benefit from differentiation with quantitative indices but requires correlation from clinical outcomes.

An artificial intelligence-driven agent for real-time head-and-neck IMRT plan generation using conditional generative adversarial network (cGAN)

PURPOSE

To develop an artificial intelligence (AI) agent for fully automated rapid head-and-neck intensity-modulated radiation therapy (IMRT) plan generation without time-consuming dose-volume-based inverse planning.

METHODS

This AI agent was trained via implementing a conditional generative adversarial network (cGAN) architecture. The generator, PyraNet, is a novel deep learning network that implements 28 classic ResNet blocks in pyramid-like concatenations. The discriminator is a customized four-layer DenseNet. The AI agent first generates multiple customized two-dimensional projections at nine template beam angles from a patient's three-dimensional computed tomography (CT) volume and structures. These projections are then stacked as four-dimensional inputs of PyraNet, from which nine radiation fluence maps of the corresponding template beam angles are generated simultaneously. Finally, the predicted fluence maps are automatically postprocessed by Gaussian deconvolution operations and imported into a commercial treatment planning system (TPS) for plan integrity check and visualization. The AI agent was built and tested upon 231 oropharyngeal IMRT plans from a TPS plan library. 200/16/15 plans were assigned for training/validation/testing, respectively. Only the primary plans in the sequential boost regime were studied. All plans were normalized to 44 Gy prescription (2 Gy/fx). A customized Harr wavelet loss was adopted for fluence map comparison during the training of the PyraNet. For test cases, isodose distributions in AI plans and TPS plans were qualitatively evaluated for overall dose distributions. Key dosimetric metrics were compared by Wilcoxon signed-rank tests with a significance level of 0.05.

RESULTS

All 15 AI plans were successfully generated. Isodose gradients outside of PTV in AI plans were comparable to those of the TPS plans. After PTV coverage normalization, D_mean of left parotid (D_AI  = 23.1 ± 2.4 Gy; D_TPS  = 23.1 ± 2.0 Gy), right parotid (D_AI  = 23.8 ± 3.0 Gy; D_TPS  = 23.9 ± 2.3 Gy), and oral cavity (D_AI  = 24.7 ± 6.0 Gy; D_TPS  = 23.9 ± 4.3 Gy) in the AI plans and the TPS plans were comparable without statistical significance. AI plans achieved comparable results for maximum dose at 0.01cc of brainstem (D_AI  = 15.0 ± 2.1 Gy; D_TPS  = 15.5 ± 2.7 Gy) and cord + 5mm (D_AI  = 27.5 ± 2.3 Gy; D_TPS  = 25.8 ± 1.9 Gy) without clinically relevant differences, but body D_max results (D_AI  = 121.1 ± 3.9 Gy; D_TPS  = 109.0 ± 0.9 Gy) were higher than the TPS plan results. The AI agent needed ~3 s for predicting fluence maps of an IMRT plan.

CONCLUSIONS

With rapid and fully automated execution, the developed AI agent can generate complex head-and-neck IMRT plans with acceptable dosimetry quality. This approach holds great potential for clinical applications in preplanning decision-making and real-time planning.

Contralateral neck failure in oral tongue cancer: Outcomes from two centers using predefined treatment criteria

BACKGROUND

The objective was to determine the incidence of, and factors associated with contralateral neck failure (CNF) in oral tongue squamous cell carcinoma (OTSCC).

METHODS

Consecutive patients with OTSCC between 2007 and 2016 were included. The predefined policy of the contralateral neck included neck dissection (ND) where the primary tumor extended/crossed midline or the contralateral neck was involved; and elective nodal irradiation (ENI) where the primary tumor was ≤1 cm from midline/2 cm from tip.

RESULTS

This study included 258 patients. ND was ipsilateral 169 (66%) and bilateral 33 (13%). Fifty-five patients (21%) received ENI to the undissected contralateral neck. CNF occurred in 19 patients (7%) and was similar by treatment received. Utilizing this approach, we observed higher rates of CNF with increasing N classification, perineural invasion, extracapsular extension, and depth of invasion ≥6 mm.

CONCLUSIONS

Using our institutional policy of treatment to the contralateral neck, a low rate of CNF (≤10%) was observed.

Impact of histological Oral Tongue Cancer margins on locoregional recurrence: A multi-centre retrospective analysis

OBJECTIVES

To assess the effect of the histological margins (HM) upon locoregional failure (LRF) and overall survival (OS) for oral tongue squamous cell carcinoma (OTSCC).

MATERIALS AND METHODS

We undertook a retrospective review of 258 patients, across two institutions, treated for OTSCC between 2007 and 2016. A Cox-proportional hazards model was used to compare the relative hazard ratio of HM to the accepted standard of 5 mm margins for LRF and OS.

RESULTS

The median follow up period was 4.8 years. The 5 year OS and freedom from LRF were 69% and 75% respectively. The Cox-proportional hazards model adjusted for age, DOI and LVI showed increasing risk of mortality and LRF with decreasing HM widths of <5 mm.

CONCLUSION

HM >5 mm were associated with a risk reduction of both LRF and mortality in OTSCC. This study supports >5 mm HM being the oncologic goal of surgery.

Quality of Life, Toxicity and Unmet Needs in Nasopharyngeal Cancer Survivors

Concerted research efforts over the last three decades have resulted in improved survival and outcomes for patients diagnosed with nasopharyngeal carcinoma (NPC). The evolution of radiotherapy techniques has facilitated improved dose delivery to target volumes while reducing dose to the surrounding normal tissue, improving both disease control and quality of life (QoL). In parallel, clinical trials focusing on determining the optimal systemic therapy to use in conjunction with radiotherapy have been largely successful, resulting in improved locoregional, and distant control. As a consequence, neoadjuvant chemotherapy (NACT) prior to definitive chemoradiotherapy has recently emerged as the preferred standard for patients with locally advanced NPC. Two of the major challenges in interpreting toxicity and QoL data from the published literature have been the reliance on: (1) clinician rather than patient reported outcomes; and (2) reporting statistical rather than clinical meaningful differences in measures. Despite the lower rates of toxicity that have been achieved with highly conformal radiotherapy techniques, survivors remain at moderate risk of persistent and long-lasting treatment effects, and the development of late radiation toxicities such as hearing loss, cranial neuropathies and cognitive impairment many years after successful treatment can herald a significant decline in QoL. Future approaches to reduce long-term toxicity will rely on: (1) identifying individual patients most likely to benefit from NACT; (2) development of response-adapted radiation strategies following NACT; and (3) anticipated further dose reductions to organs at risk with proton and particle therapy. With increasing numbers of survivors, many in the prime of their adult life, research to identify, and strategies to address the unmet needs of NPC survivors are required. This contemporary review will summarize our current knowledge of long-term toxicity, QoL and unmet needs of this survivorship group.

Radiation therapy quality assurance in head and neck radiotherapy - Moving forward

Head and Neck Cancer (HNC) radiation oncologists (ROs) enjoy the immense pleasure of curing patients, working within a large multidisciplinary team to effectively deliver curative intent treatment whilst also aiming to minimise late treatment toxicity. Secondary analyses of large-scale HNC clinical trials have shown the critical impact of the quality of radiotherapy plans, where protocol non-compliant plans have yielded inferior survival rates approximating 20%. The peer review process in routine day-to-day HNC practice shows that even in major academic centers a significant proportion of RT plans may require changes to the radiotherapy planning volume. Optimising the therapeutic ratio in HNC has been dramatically facilitated by intensity modulated radiotherapy (IMRT), but that technology has also increased the complexity of HNC radiotherapy treatment and high-volume centers with experienced clinicians may be best placed to deliver this most accurately. International consensus guidelines to standardise or benchmark best practice with respect to the RT-QA process in HNC are needed. The aim of this paper is to highlight the importance of the RT-QA process in the HNC treatment process and to make some recommendations for its inclusion in both clinical trials and routine clinical practice.