How a very large sarcomatoid lung cancer was efficiently managed with lattice radiation therapy: a case report.

Background: The management of large tumors represent a concerning issue in the palliative setting. Since a surgical approach is excluded and systemic therapy has reported limited efficacy, the patients are commonly referred for radiation therapy as last resort. However, to improve quality of life and to avoid excessive toxicity, low doses of palliative radiotherapy (RT) are delivered. In these cases, with limited and short response. Lattice radiation therapy (LRT) represents an innovative technique aiming to increase tumor response without enhancing adjacent organs at risk (OAR) toxicity, by administering inhomogeneous doses with ablative high dose areas inside the tumor and low doses near the OAR.

Case Description: A 69-year-old male patient was admitted to our hospital complaining of sacral pain and mild dyspnea. After a suspicious opacity on X-ray, the chest computed tomography (CT), the positron emission tomography/CT (PET/CT) and the endobronchial ultra sound-guided transbronchial needle aspiration confirmed the diagnosis of a bulky sarcomatoid lung cancer (stage IV: cT4N3M1c). After an effective antalgic RT on the sacral metastasis and three lines of systemic therapy without response, the patient started to have a disabling dyspnea. Thus, we administered LRT on the bulky lesion. The patients experienced no significant toxicity, with a marked lesion response on the 3 month-follow CT and a significant improvement in symptoms and in his daily life.

Conclusions: This is the first LRT treatment done in our Center and it provides another evidence in the efficacy of LRT planning. It shows how LRT could represent an innovative technique to provide durable response in large tumors, without increasing treatment-related toxicity.