Pulmonary tumors, whether primary or metastatic, represent a major challenge in oncology.

Primary lung cancers are responsible for nearly 37,000 deaths per year in France, highlighting the critical importance of their management. Moreover, secondary pulmonary lesions are present in 20% of solid cancers and show wide variability in prognosis. Oligometastatic disease (≤ 3 to 5 lesions) is associated with a better prognosis, justifying the development of local treatments for these lesions, particularly stereotactic radiotherapy.

During the COVID-19 pandemic, single-fraction protocols (30-34 Gy) were implemented to limit patient exposure, showing outcomes equivalent to multi-fraction regimens for both primary and secondary lesions.

However, the impact of these treatments on quality of life remains poorly documented-especially for non-small cell lung carcinoma-and needs to be further explored to optimize their integration into routine clinical practice.

The primary objective of this study is to assess the impact of single-fraction stereotactic body radiotherapy (SBRT) for pulmonary lesions on quality of life.

To this end, patients will complete a standardized French-language quality of life questionnaire, the EORTC QLQ-C30 and LC-29, before treatment and at 1 month (M1), 3 months (M3), 6 months (M6), 9 months (M9), and 12 months (M12) after treatment.

This validated, disease-specific questionnaire comprises 59 items: 30 assessing overall quality of life (QLQ-C30) and 29 addressing aspects related to lung cancer treatments (LC-29). It includes questions on respiratory symptoms, chest pain, fatigue, and the functional impact of the treatment.

Pulmonary tumors, whether primary or metastatic, represent a major challenge in oncology. Lung cancer remains the leading cause of cancer-related mortality in France, with nearly 37,000 annual deaths. Pulmonary metastases, present in approximately 20% of patients with solid tumors, highlight the complexity of managing secondary tumors, particularly in the context of oligometastatic cancers. These cancers, characterized by a limited number of metastases (generally ≤3 to 5), have garnered increasing attention due to their potentially improved prognosis with the use of local ablative therapies.

Stereotactic body radiotherapy (SBRT) is a technique that delivers high doses of radiation with great precision over a limited number of sessions (1 to 5 fractions compared to around 30 in conventional radiotherapy). For primary lesions, SBRT has demonstrated local control rates exceeding 90% and a 5-year survival rate of 87% (Chang et al., 2015). Similarly, promising outcomes have been reported for oligometastatic pulmonary lesions, with improvements in progression-free and overall survival compared to standard of care. Consequently, SBRT has become a key therapeutic option for pulmonary tumors, whether primary or secondary.

During the recent COVID-19 pandemic, monofraction protocols (30 or 34 Gy) were implemented. Their equivalence has been demonstrated for both primary lesions and secondary lesions, and they have been included in clinical guidelines. Single-session treatments are particularly advantageous for patients with poor general health or those living far from treatment centers, as they help to minimize travel requirements.

However, although SBRT in a single fraction offers promising prospects, data on its impact on quality of life remain limited, especially for patients with non-small cell lung cancer. Such information is crucial to guide the integration of this strategy into clinical practice and to assess its benefits in the context of personalized care.

This bicentric ambispective observational study (RIPH 3 according to the Jardé Law) aims to evaluate the quality of life of patients treated with single-fraction pulmonary SBRT using the EORTC QLQ C30 and LC-29 questionnaires. The primary endpoint will be analyzed prospectively in newly treated patients, while retrospective data will be included for secondary endpoints: tolerance (specifically grade ≥ 3 toxicities), efficacy (local control, progression-free survival, overall survival), and dosimetric parameters. The study involves patients with primitive (NSCLC T1-2N0) or oligometastatic (≤ 3 tumors) lung tumor who are inoperable or refuse surgery, treated with stereotactic radiotherapy delivering 34 Gy in a single session at two cancer centers (Institut de Cancérologie de Montpellier and Institut de Cancérologie de Lorraine). Patients will be asked to complete standardized quality-of-life questionnaires in French, the EORTC QLQ C30 and LC-29, pre-treatment, at M1, M3, M6, M9 and M12. These questionnaire completion times correspond to standard radiological assessments as part of the patient's medical management and follow-up.

Inclusion Criteria:

• Age: ≥ 18 years
• Patient receiving single-fraction stereotactic body radiation therapy (SBRT)
• Stage T1-2 N0 M0 non-small cell lung cancer (NSCLC) (AJCC 6th edition) or oligometastatic lung tumor defined by ≤ 3 lung metastasis.
• Inoperability: Tumor is inoperable or patient refuses surgery
• Tumor size: ≤ 3 cm
• Peripheral tumors: > 2 cm from proximal bronchial tree but ≥ 0.5 cm from the wall
• Histologically proven or with evolution criteria (CT scan and PET scan)
• ECOG performance status: 0-2
• Ability to comply: Willingness and ability to comply with scheduled visits and other study procedures
• Informed consent: Written informed consent obtained
• Insurance: Patient is affiliated with a French health insurance plan

Exclusion Criteria:

• Tumors invading the pleura or mediastinum.
• Concurrent infectious pneumonia or pericarditis.
• Prior radiotherapy to the treatment field.
• Presence of neoadjuvant treatment for the present cancer.
• Substance abuse, medical, psychological, or social conditions that may interfere with the patient's participation in the study or evaluation of the study results
• Patients under guardianship, curatorship or safeguard of justice,
• Pregnant or breast-feeding subjects
• Concomitant participation or participation within the last 30 days in another clinical trial
• Patient with an estimated life expectancy of less than 6 months.

Prospective part:

The target population for the prospective part of the study consists of patients aged 18 years or older, treated at ICM or ICL for peripheral T1-2 N0 non-small cell lung carcinoma or non-operable oligometastatic secondary lesions, managed with stereotactic body radiotherapy (SBRT).

Retrospective part:

The target population for the retrospective part of the study consists of patients aged 18 years or older, treated at ICM or ICL for peripheral T1-2 N0 non-small cell lung carcinoma or non-operable oligometastatic secondary lesions, managed with stereotactic body radiotherapy (SBRT) between July 2020 and August 2025.