Improved adaptive radiotherapy to adjust for anatomical alterations during curative treatment for locally advanced lung cancer

Factors that Influence the Need to Start Adaptive Radiotherapy

Introduction

Adaptive radiotherapy (ART) is an essential approach to account for anatomical and biological uncertainties. Adaptive radiotherapy is, however, time-consuming, and it is unclear which patients are eligible or when is the best time to start ART.

Methods

This prospective study was conducted at Kasr El-Aini Center of Clinical Oncology and Nuclear Medicine, Cairo, Egypt from January 2019 to December 2020. Thirty patients with pathologically proven, limited-stage small cell or stage I-II non-small cell lung cancer who were either not fit for or refused surgery or had stage III disease were recruited and underwent treatment planning to receive 60 Gy on a conventional 3D conformal radiation schedule with platinum-based chemotherapy. All patients underwent computed tomography (CT) planning within 2 and 4 weeks of starting radiation therapy to assess the need for adaptation. Pulmonary function test and echocardiography findings were assessed at the end of treatment and at 3 and 6 months after treatment, and were compared to the baseline.

Results

We found a significant reduction in mean value of the planning target volume (PTV) in the CT scans at the second (331 cm3) and fourth (257 cm3) weeks of treatment as compared to baseline (342 cm3) (p-value < 0.0001). Adaptation decreased the dose to the organ at risk with statistical significance and with improvement of the target coverage. At week 2 of radiotherapy, the need for adaptation was correlated to the conformity index (p = 0.0473), esophageal V35 (p = 0.0488), esophageal V50 (p = 0.0295), and its mean dose (p = 0.0087). At week 4 it was correlated to forced expiratory volume in 1 second (FEV1) (p = 0.0303), ratio between the forced expiratory volume in 1 second and the forced vital capacity (FEV1/FVC) (p = 0.0024), and echocardiography (p = 0.0183).

Conclusions

Conformity index and esophageal dose constraints can predict the need for adaptation at week 2, whereas baseline pulmonary function parameters and echocardiography can predict the need for adaptation at week 4 of radiotherapy.

Factors associated with failure to start consolidation durvalumab after definitive chemoradiation for locally advanced NSCLC

Introduction

The introduction of consolidation immunotherapy after chemoradiotherapy has improved outcome for patients with locally advanced non-small cell lung cancer. However, not all patients receive this treatment. This study identifies factors associated with failure to start durvalumab as consolidation therapy with the aim of optimizing treatment, supportive care and prehabilitation to ensure that more patients complete the planned treatment.

Materials and methods

Patients from two clinical trials and a named patient use program, were included in this study. All patients received platinum-doublet chemotherapy concomitant with radiotherapy to a total dose of 60-66 gray. Patient characteristics, cancer treatment, toxicity, performance status and laboratory data before and after chemoradiotherapy were recorded and patients who never started durvalumab were compared with those who did.

Results

A total of 101 patients were included, of which 83 started treatments with durvalumab after chemoradiotherapy. The 18 patients who did not start durvalumab had significantly higher lactate dehydrogenase at baseline and a worse performance status, cumulative toxicity and higher c-reactive protein after completed chemoradiotherapy. Data also suggest that pre-treatment diabetes and reduced hemoglobin and/or diffusion capacity of the lungs for carbon monoxide contribute to the risk of treatment abruption.

Conclusion

Treatment plan disruption rate was 18%. Systemic inflammation and performance status were associated with failure to receive durvalumab after chemoradiation. Further studies are needed to confirm findings and prospective trials should investigate whether prehabilitation and supportive treatment could help more patients finishing the planned treatment.

Clinical Trial Registration

clinicaltrials.gov, identifier NCT03798535; NCT04392505.