Toxicity and efficacy of stereotactic body radiotherapy for ultra-central lung tumours: a single institution real life experience

Abstract

Objectives: The use of stereotactic body radiotherapy (SBRT) to treat ultra-central lung tumours remains more controversial than for peripheral and central tumours. Our objective was to assess toxicities, local control (LC) rate and survival data in patients with ultra-central lung tumours treated with SBRT. Methods: We conducted a retrospective and monocentric study about 74 patients with an ultra-central lung tumour, consecutively treated between 2012 and 2018. Ultra-central tumours were defined as tumours whose planning target volume overlapped one of the following organs at risk (OARs): the trachea, right and left main bronchi, intermediate bronchus, lobe bronchi, oesophagus, heart. Results: Median follow-up was 25 months. Two patients (2.7%) showed Grade 3 toxicity. No Grade 4 or 5 toxicity was observed. 11% of patients experienced primary local relapse. LC rate was 96.7% at 1 year and 87.6% at 2 years. Median progression free survival was 12 months. Median overall survival was 31 months. Conclusion: SBRT for ultra-central tumours remains safe and effective as long as protecting organs at risk is treatment-planning priority. Advances in knowledge: The present study is one of the rare to describe exclusively ultra-central tumours through real-life observational case reports. Globally, literature analysis reveals a large heterogeneity in ultra-central lung tumours definition, prescribed dose, number of fractions. In our study, patients treated with SBRT for ultra-central lung tumours experienced few Grade 3 toxicities (2.7%) and no Grade 4 or 5 toxicities, due to the highest compliance with dose constraints to OARs. LC remained efficient.

Survival and Prognostic Factors of Ultra-Central Tumors Treated with Stereotactic Body Radiotherapy

“…To our knowledge, most of the published studies investigating only ultra-central lung tumors analyzed the high-risk indicators for treatment-related mortality or local control, excluding clinical factors significantly associated with better OS or PFS, except for the study of Breen et al [ 21 ]. Interestingly, unlike previous literature [ 17 , 19 , 30 ], this study identified female gender, age < 70 years, and tumor-trachea distance ≤ 5 mm as independent prognostic factors associated with better OS. Moreover, patients with a tumor size < 5 cm were significantly associated with better OS as compared to patients with a tumor size ≥ 5 cm.…”

“…Similar results were reported by Breen et al [ 21 ] and Lodeweges et al [ 19 ], with 1-year and 2-year OS rates of 78% and 57%, and 77% and 52%, respectively. One-year LC was 97% in the study reported by Guillaume et al [ 17 ], and 98% in the work by Lodeweges et al [ 19 ], slightly higher than our findings. Across the studies investigating SBRT for ultra-central tumors, there was a significant heterogeneity in terms of fractionation schedules.…”

“…According to the previous literature [ 16 , 17 , 24 ], no grade 4 or 5 with a very low rate of acute (1%), and late (4%) G3 events, were reported [ 19 ]. Acute and late G3 dyspnea were experienced by 1 and 4 patients, respectively.…”

“…The different rates of treatment-related toxicity can be explained by the decision of some authors to strictly prioritize the respect of OARs dose constraints rather than the PTV coverage [ 16 , 17 , 24 ] in order to avoid high risk of acute toxicity such as dysphagia, esophagitis, and airway bleeding. Moreover, adequately identifying critical normal structures is a mandatory step of the treatment planning process which was missing in the HILUS trial [ 39 ].…”

Curative‐intent treatment of pulmonary metastases from colorectal cancer: A comparison between imaging‐guided thermal ablation and surgery

“…29 For organizational reasons, IGTA is preferred over SBRT at our institution except for ultracentral PM, contraindicated for IGTA and which would require extensive lung resection. 30 Groups were not comparable per se as indications were different, but similar results were observed after PSM analysis nonetheless. It is likely that length of stay would decrease after surgery while implementing enhanced recovery strategies.…”