Clinical features and risk factors for interstitial lung disease spreading in low-dose irradiated areas after definitive radiotherapy with or without durvalumab consolidation therapy for patients with non-small cell lung cancer.

BACKGROUND: The current standard of care for patients with unresectable locally advanced non-small cell lung cancer (NSCLC) is chemoradiotherapy (CRT) combined with durvalumab consolidation therapy. However, radiotherapy (RT) always carries the risk of radiation pneumonitis (RP), which can preclude durvalumab continuation. In particular, the spread of interstitial lung disease (ILD) in low-dose areas or extending beyond the RT field often makes it difficult to determine the safety of continuation or rechallenging of durvalumab. Thus, we retrospectively analyzed ILD/RP after definitive RT with and without durvalumab, with assessment of radiologic features and dose distribution in RT. METHODS: We retrospectively evaluated the clinical records, CT imaging, and radiotherapy planning data of 74 patients with NSCLC who underwent definitive RT at our institution between July 2016 and July 2020. We assessed the risk factors for recurrence within one year and occurrence of ILD/RP. RESULTS: Kaplan-Meier method showed that ≥ 7 cycles of durvalumab significantly improved 1-year progression free survival (PFS) (p < 0.001). Nineteen patients (26%) were diagnosed with ≥ Grade 2 and 7 (9.5%) with ≥ Grade 3 ILD/RP after completing RT. There was no significant correlation between durvalumab administration and ≥ Grade 2 ILD/RP. Twelve patients (16%) developed ILD/RP that spread outside the high-dose (> 40 Gy) area, of whom 8 (67%) had ≥ Grade 2 and 3 (25%) had Grade 3 symptoms. In unadjusted and multivariate Cox proportional-hazards models adjusted for V20 (proportion of the lung volume receiving ≥ 20 Gy), high HbA1c level was significantly correlated with ILD/RP pattern spreading outside the high-dose area (hazard ratio, 1.842; 95% confidence interval, 1.35-2.51). CONCLUSIONS: Durvalumab improved 1-year PFS without increasing the risk of ILD/RP. Diabetic factors were associated with ILD/RP distribution pattern spreading in the lower dose area or outside RT fields, with a high rate of symptoms. Further study of the clinical background of patients including diabetes is needed to safely increase the number of durvalumab doses after CRT.

Low-Dose Volumetric Modulated Arc Therapy for a Patient With Head and Neck Involvement of Mycosis Fungoides: A Case Report With a Review of Literature.

Mycosis fungoides (MF) is the most common type of cutaneous T-cell lymphoma that slowly progresses over a period of years to decades. In some cases, lesions that spread to the scalp, neck, or facial skin can have a significant impact on cosmetic appearance and a patient's quality of life. Among the various treatments, radiation therapy is one of the most effective treatment modalities for patients with symptomatic cutaneous lesions. We report on an MF patient who had gradually increasing patches and plaques on the scalp, face, and neck and who underwent irradiation with 20 Gy administered in 10 fractions using volumetric modulated arc therapy. After undergoing this highly conformal technique, the patient obtained prolonged local control and significant alleviation of symptoms with acceptable adverse events. This technique constitutes a promising approach for treating a complex target due to its ability to provide homogeneous coverage of irregularly shaped target volumes along with its ability to preserve organs at risk. In addition, we systematically reviewed clinical reports on the management of extensive cutaneous lesions in MF patients undergoing other irradiation techniques.