What is the optimal radiotherapy utilization rate for lung cancer?-a systematic review

Impact of the COVID-19 Pandemic on Outcomes for Patients with Lung Cancer Receiving Curative-intent Radiotherapy in the UK

AIMS

Previous work found that during the first wave of the COVID-19 pandemic, 34% of patients with lung cancer treated with curative-intent radiotherapy in the UK had a change to their centre's usual standard of care treatment (Banfill et al. Clin Oncol 2022;34:19-27). We present the impact of these changes on patient outcomes.

MATERIALS AND METHODS

The COVID-RT Lung database was a prospective multicentre UK cohort study including patients with stage I-III lung cancer referred for and/or treated with radical radiotherapy between April and October 2020. Data were collected on patient demographics, radiotherapy and systemic treatments, toxicity, relapse and death. Multivariable Cox and logistic regression were used to assess the impact of having a change to radiotherapy on survival, distant relapse and grade ≥3 acute toxicity. The impact of omitting chemotherapy on survival and relapse was assessed using multivariable Cox regression.

RESULTS

Patient and follow-up forms were available for 1280 patients. Seven hundred and sixty-five (59.8%) patients were aged over 70 years and 603 (47.1%) were female. The median follow-up was 213 days (119, 376). Patients with stage I-II non-small cell lung cancer (NSCLC) who had a change to their radiotherapy had no significant increase in distant relapse (P = 0.859) or death (P = 0.884); however, they did have increased odds of grade ≥3 acute toxicity (P = 0.0348). Patients with stage III NSCLC who had a change to their radiotherapy had no significant increase in distant relapse (P = 0.216) or death (P = 0.789); however, they did have increased odds of grade ≥3 acute toxicity (P < 0.001). Patients with stage III NSCLC who had their chemotherapy omitted had no significant increase in distant relapse (P = 0.0827) or death (P = 0.0661).

CONCLUSION

This study suggests that changes to radiotherapy and chemotherapy made in response to the COVID-19 pandemic did not significantly affect distant relapse or survival. Changes to radiotherapy, namely increased hypofractionation, led to increased odds of grade ≥3 acute toxicity. These results are important, as hypofractionated treatments can help to reduce hospital attendances in the context of potential future emergency situations.

Dyspnea in patients with stage IV non-small cell lung cancer: a population-based analysis of disease burden and patterns of care

Background

Patients with metastatic non-small cell lung cancer (NSCLC) experience significant morbidity with dyspnea being a common symptom with a prevalence of 70%. The objective of this study was to determine factors associated with a moderate-to-severe dyspnea score based on the Edmonton Symptom Assessment System (ESAS), as well as resultant patterns of intervention and factors correlated to intervention receipt.

Methods

Using health services administrative data, we conducted a population-based study of all patients diagnosed with metastatic NSCLC treated from January 2007 to September 2018 in the province of Ontario. The primary outcomes of interest are the prevalence of moderate-to-severe dyspnea scores, and the receipt of dyspnea-directed intervention. Differences in baseline characteristic between moderate-to-severe dyspnea and low dyspnea score cohorts were assessed by comparative statistics. Predictors of intervention receipt for patients with moderate-to-severe dyspnea scores were estimated using multivariable modified Poisson regression.

Results

The initial study cohort included 13,159 patients diagnosed with metastatic NSCLC and of these, 9,434 (71.7%) reported a moderate-to-severe dyspnea score. Compared to patients who did not report moderate-to-severe dyspnea scores, those who reported a moderate-to-severe dyspnea score were more likely to complete a greater number of ESAS surveys, be male, have a higher Elixhauser comorbidity index (ECI) score, and receive subsequent systemic therapy after diagnosis. Most patients with a moderate-to-severe dyspnea score received intervention (96%), of which the most common were palliative care management (87%), thoracic radiotherapy (56%) and thoracentesis (37%). Multivariable regression identified older patients to be less likely to undergo pleurodesis. Thoracentesis was less common for patients living in rural and non-major urban areas, lower income areas, and earlier year of diagnosis. Receipt of thoracic radiotherapy was less common for older patients, females, those with ECI ≥4, patients living in major urban areas, and those with later year of diagnosis. Finally, palliative care referrals were less frequent for patients with ECI ≥4, age 60-69, residence outside of major urban areas, earlier year of diagnosis, and lower income areas.

Conclusions

Dyspnea is a prevalent symptom amongst patients with metastatic NSCLC. Subpopulations of patients with moderate-to-severe dyspnea scores were in which inequities may exist in access to care that require further attention and evaluation.

Cobalt compensator-based IMRT device: A treatment planning study of head and neck cases

PURPOSE

Our goal is to develop a novel cobalt-compensator-based IMRT device for low- and middle-income countries that is reliable and cost-effective while delivering treatment plans of equal quality to those from linac-MLC devices. The present study examines the quality of treatment plans using this device.

METHODS

A commercial treatment planning system (TPS; RayStation v.8B) was commissioned for this device using Monte Carlo simulations from the Geant4 toolkit. Patient-specific compensators were created as regions-of-interest. Thirty clinical head & neck cases were planned and compared to clinical plans with a 6MV linac using IMRT. The mock head and neck plan from TG-119 was used for further validation.

RESULTS

PTV objectives were achieved in all 30 plans with PTV V95% >95 %. OAR sparing was similar to clinical plans. There were 14 cases where OAR dose limits exceeded the recommended QUANTEC limits in the clinical plan in order to achieve target coverage. OAR sparing was better in the cobalt compensator plan in 8 cases and worse in 3 cases, in the latter cases exceeding the clinical plan doses by an average of 8.22 % (0.0 %-13.5 %). Average field-by-field gamma pass-rate were 93.7 % (2 %/2mm). Estimated treatment times using the Co-60 compensator device were 1 min 27 s vs 1 min 2 s for the clinical system.

CONCLUSION

This system is the first of its kind to allow for IMRT with a Co-60 device. Data here suggests that the delivery meets plan quality criteria while maintaining short treatment times which may offer a sustainable and cost-low option for IMRT on the global scale.

Optimal and actual rates of Stereotactic Ablative Body Radiotherapy (SABR) utilisation for primary lung cancer in Australia

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Stereotactic Ablative Body Radiotherapy (SABR) plays a major role in the management of early-stage non-small cell lung cancer (NSCLC).

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An evidence-based model is developed to estimate optimal rates of lung SABR utilisation within the Australian population.

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Optimal utilisation rates are compared against actual utilisation rates to evaluate service provision.

Background and purpose

Radiotherapy utilisation rates considerably vary across different countries and service providers, highlighting the need to establish reliable benchmarks against which utilisation rates can be assessed. Here, optimal utilisation rates of Stereotactic Ablative Body Radiotherapy (SABR) for lung cancer are estimated and compared against actual utilisation rates to identify potential shortfalls in service provision.

Materials and Methods

An evidence-based optimal utilisation model was constructed after reviewing practice guidelines and identifying indications for lung SABR based on the best available evidence. The proportions of patients likely to develop each indication were obtained, whenever possible, from Australian population-based studies. Sensitivity analysis was performed to account for variations in epidemiological data. Practice pattern studies were reviewed to obtain actual utilisation rates.

Results

A total of 6% of all lung cancer patients were estimated to optimally require SABR at least once during the course of their illness (95% CI: 4–6%). Optimal utilisation rates were estimated to be 32% for stage I and 10% for stage II NSCLC. Actual utilisation rates for stage I NSCLC varied between 6 and 20%. For patients with inoperable stage I, 27–74% received SABR compared to the estimated optimal rate of 82%.

Conclusion

The estimated optimal SABR utilisation rates for lung cancer can serve as useful benchmarks to highlight gaps in service delivery and help plan for more adequate and efficient provision of care. The model can be easily modified to determine optimal utilisation rates in other populations or updated to reflect any changes in practice guidelines or epidemiological data.

Model Calibration of Pharmacokinetic-Pharmacodynamic Lung Tumour Dynamics for Anticancer Therapies

Individual curves for tumor growth can be expressed as mathematical models. Herein we exploited a pharmacokinetic-pharmacodynamic (PKPD) model to accurately predict the lung growth curves when using data from a clinical study. Our analysis included 19 patients with non-small cell lung cancer treated with specific hypofractionated regimens, defined as stereotactic body radiation therapy (SBRT). The results exhibited the utility of the PKPD model for testing growth hypotheses of the lung tumor against clinical data. The model fitted the observed progression behavior of the lung tumors expressed by measuring the tumor volume of the patients before and after treatment from CT screening. The changes in dynamics were best captured by the parameter identified as the patients’ response to treatment. Median follow-up times for the tumor volume after SBRT were 126 days. These results have proven the use of mathematical modeling in preclinical anticancer investigations as a potential prognostic tool.