Different benefits of adaptive radiotherapy for different histologies of NSCLC

Abstract

Background

Adenocarcinoma (AC) and squamous cell carcinoma (SCC) are the most frequent histological subtypes of non-small cell lung cancer (NSCLC). The aim of this study was to investigate how patients with AC and SCC benefit from image-guided adaptive radiotherapy (ART) with tumour match.

Material and methods

Consecutive patients diagnosed with AC or SCC of the lung treated with definitive chemo-radiotherapy before and after the implementation of ART and tumour match were retrospectively included for analyses. Data collection included baseline patient and treatment characteristics in addition to clinical data on radiation pneumonitis (RP), failure, and survival. Patients were divided into four categories based on their histology and treatment before (n = 173 [89 AC and 84 SCC]) and after implementation of ART (n = 240 [141 AC and 99 SCC]).

Results

Median follow-up was 5.7 years for AC and 6.3 years for SCC. Mean lung dose decreased for both histologies with ART, whereas mean heart dose only decreased for patients with AC. Incidences of grade 3 and 5 RP decreased for both histologies with ART. Loco-regional failure (LRF) rates decreased significantly for patients with SCC after ART (p = .04), no significant difference was observed for AC. Overall survival (OS) increased significantly for SCC after ART (p < .01): the 2-year OS increased from 31.0% (95% confidence interval [CI] [22.5–42.6]) to 54.5% (95% CI [45.6–65.3]). No significant effect on OS was observed for patients with AC.

Conclusion

ART and tumour match in the radiotherapeutic treatment of patients with locally advanced NSCLC primarily led to decreased LRF and improved OS for patients with SCC.

Keywords:

• NSCLC
• adaptive radiotherapy
• squamous cell carcinoma
• adenocarcinoma

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The participants of this study did not give written consent for their data to be shared publicly, so due to the sensitive nature of the research supporting data is not available.

Additional information

Funding

Marie Tvilum was supported by the Health Research Foundation of Central Denmark Region. Ditte Sloth Møller, Lone Hofmann, and Marie Tvilum were supported by the DCCC Radiotherapy – The Danish National Research Center for Radiotherapy, Danish Cancer Society (grant no. R191-A11526), and Danish Comprehensive Cancer Center. Ditte Sloth Møller, Christina Maria Lutz, Marianne Knap, and Marie Tvilum were supported by the Danish Cancer Society (grant nos. R209-A13036 and R325-A18822). Christina Maria Lutz was supported by the Danish Cancer Society (grant no. R90-A6244). Ane Appelt was supported by Cancer Research UK and Yorkshire Cancer Research.