Radiotherapy for Extramedullary Leukaemic Manifestation (Chloroma)

Purpose: Extramedullary leukaemic disease (EMD, synonym chloroma) is a rare solid manifestation of myeloid leukaemia for which the value of radiotherapy (RT) as a treatment strategy remains controversial. The aim of this study is to analyse the effectiveness of various RT doses for EMD in the modern treatment era.

Materials And Methods: Between January 2000 and June 2016, 20 patients with total of 45 lesions underwent RT for EMD at our institution.

Results: With a median radiation dose of 26 Gy (range 4-42 Gy), local remission could be achieved in 91% of patients (complete remission rate: 71%). The median duration of local control (DOLC) was 17 months (95% confidence interval [CI] 0.5-33) and the median overall survival (OS) after chloroma onset was 24 months (95% CI 11-38). No noticeable difference between high- and low-dose regimens has been observed (74% versus 68%; P = 0.5). In the multivariate analysis, only Eastern Cooperative Oncology Group (ECOG) score and bone marrow state during RT have proven to be determinant for durable local control and OS.

Conclusions: Low-dose RT (≤26 Gy) achieves good local control compared to high-dose regimes. Bone marrow state during RT and ECOG score during RT may play a crucial role, influencing both DOLC and OS.