Dosimetric and Clinical Outcomes with Intensity-modulated Radiation Therapy after Chemotherapy for Patients with Early-stage Diffuse Large B-cell Lymphoma of Waldeyer’s Ring

Publication date: Available online 8 June 2016
Source:International Journal of Radiation Oncology*Biology*Physics
Author(s): Yong-Gang Xu, Shu-Nan Qi, Shu-Lian Wang, Yue-Ping Liu, Wei-Hu Wang, Jing Jin, Yong-Wen Song, Hua Ren, Hui Fang, Xiao-Hui He, Mei Dong, Bo Chen, Ning-Ning Lu, Ning Li, Yuan Tang, Yu Tang, Jian-Rong Dai, Ye-Xiong Li
PurposeTo assess the dosimetric benefit, prognosis and toxicity of intensity-modulated radiation therapy (IMRT) for early-stage, diffuse large B-cell lymphoma of Waldeyer's ring (WR-DLBCL).Methods and MaterialsSixty-one patients with early-stage WR-DLBCL who received chemotherapy followed by IMRT were retrospectively reviewed. Dosimetric parameters for the target volume and critical normal structures were evaluated and survival calculated. Linear regression analysis was used to assess the effect of the mean dose (Dmean) to the parotid glands upon xerostomia.ResultsThe median Conformity Index (CI) and Homogeneity Index (HI) of the planning target volume (PTV) were 0.83 and 0.90, respectively, demonstrating very good coverage of the target volume. Mean dose to the parotid glands was 24.9 Gy. Five-year overall survival (OS), progression-free survival (PFS), and locoregional control (LRC) were 94.7%, 93.1%, and 98.3%, respectively. Early and late toxicities were mild, and no patient developed late toxicities of grade ≥3. Dmean to the parotid glands had a linear correlation with late xerostomia of grade ≥2.ConclusionsIMRT after chemotherapy can provide excellent dose conformity and achieve favorable survival and LRC with mild toxicities in patients with early-stage WR-DLBCL. Dose constraints for the parotid glands should be limited to <24 Gy for early-stage WR-DLBCL.

Teaser

The dosimetric benefit, efficacy and toxicity of intensity-modulated radiation therapy (IMRT) for early-stage diffuse large B-cell lymphoma of Waldeyer's ring have not been addressed specifically. We demonstrated that IMRT elicits excellent target volume coverage and sparing of the parotid glands, and achieves favorable survival with mild toxicity. Dose constraints for the parotid glands should be <24 Gy in such patients.


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