Radiation Pneumonitis Changes over Time after Stereotactic Body Radiation Therapy for Lung Tumors: Post-treatment Cavity (Sunny-side-up Egg-like) Changes

• Published in: Anticancer research 2016-10, Vol.36 (10), p.5563-5570
• Main Authors: Maebayashi, Toshiya, Ishibashi, Naoya, Aizawa, Takuya, Sakaguchi, Masakuni, Sato, Tsutomu, Kawamori, Jiro, Tanaka, Yoshiaki
• Format: Article
• Language: English
• Subjects: Aged; Aged, 80 and over; Carcinoma, Non-Small-Cell Lung - radiotherapy; Female; Humans; Lung Neoplasms - radiotherapy; Male; Radiation Pneumonitis - pathology; Radiosurgery
• ISSN: 0250-7005; 1791-7530
• DOI: 10.21873/anticanres.11141

Stereotactic body radiation therapy (SBRT) is a viable treatment option for stage I non-small cell lung carcinoma (NSCLC) in non-surgical candidates. Although treatment with a 100 Gy biological effective dose is considered to carry a low risk of local recurrence, only a few reports have focused on changes in tumors or surrounding intact portions of the lung after SBRT. Such changes are assessed using diagnostic imaging specifically for radiation pneumonitis, which can be difficult to distinguish from local tumor recurrence. Cavity changes after SBRT observed around the tumor within the irradiated field resemble an egg, fried with the yolk facing upward, and are thus referred to as 'sunny-side-up egg-like' changes. They have the appearance of a residual tumor in the center. This study aimed to evaluate patients with post-treatment cavity changes after SBRT for stage I NSCLC. Cavity changes were observed in four cases. Tumors were irradiated with a 6-MV X-ray using 10 fixed ports. The single dose was 12 Gy, the total dose 48 Gy. The time until the appearance of cavity changes ranged from 4 to 9 months (median=6 months). The cavity changes disappeared in 12-20 months (median=16 months). Cavity changes (sunny-side-up egg-like) in the lungs may develop after SBRT for stage I NSCLC.