Correspondence Address:
Efstathios Kamperis
Department of Radiation Oncology, Papageorgiou General Hospital, Thessaloniki
Greece

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Sir,

We read with great interest the article by Pulle et al. concerning two rare complications, esophageal perforation and aortic rupture, in a single patient with lung cancer that was attributed to radiation therapy.[1] We would like to congratulate the authors on the successful management of these dreadful complications and also raise some points.

Radiation injury of mediastinal structures following stereotactic body radiation therapy (SBRT) is a well-recognized toxicity and has led to the introduction of the “no-fly” zone.[2] This is an area around the proximal bronchial tree, heart, major vessels, and esophagus where SBRT is avoided due to life-threatening toxicity. However, this patient received fractionated radiotherapy, not SBRT, and at a relatively moderate dose of 54 Gy. In a retrospective study from Singh et al., in 207 patients with lung cancer undergoing fractionated radiotherapy, no case of Grade 3–5 esophageal toxicity occurred when the maximal point dose to the esophagus was <58 Gy.[3] Regarding aorta dose tolerance, we have some data from re-irradiation cohorts. Thirty-five patients who received two courses of radiation therapy for thoracic tumors, with daily fraction 1.2–3.0 Gy, had 0% risk for Grade 5 aorta toxicity when the composite dose to the aorta was 120.0 Gy, as a raw dose, and 90.0 Gy when the dose was corrected for long-term recovery during the retreatment interval.[4] Another re-irradiation study with 33 patients had a single Grade 5 event with an aortoesophageal fistula after receiving an estimated aortic 2 Gy equivalent composite maximum dose of 200 Gy.[5] Besides dose, the timing of complications' manifestation is not congruent with radiation-induced toxicity, particularly the esophageal perforation that occurred immediately after the completion of radiotherapy. Finally, the patient underwent two major operations in the thorax (a lobectomy and a pneumonectomy), with adjuvant chemotherapy and a local recurrence in between, all of which could have contributed to tissue damage. Therefore, we think that the etiopathogenesis of the complications is multifactorial in nature, and although radiotherapy likely triggered these dramatic events, it was not exclusively responsible for them.

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Conflicts of interest

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