Does Unintentional Splenic Radiation Predict Outcomes After Pancreatic Cancer Radiation Therapy?

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• 作者：Awalpreet S. Chadha ; MD^&lowast ; ; Guan Liu ; MD^&lowast ; ; Hsiang-Chun Chen ; PhD^&dagger ; ; Prajnan Das ; MD^&lowast ; ; Bruce D. Minsky ; MD^&lowast ; ; Usama Mahmood ; MD^&lowast ; ; Marc E. Delclos ; MD^&lowast ; ; Yelin Suh ; PhD^&Dagger ; ; Gabriel O. Sawakuchi ; PhD^&Dagger ; ; ^§ ; ; Sam Beddar ; PhD^&Dagger ; ; Matthew H. Katz ; MD^‖ ; Jason B. Fleming ; MD^‖ ; Milind M. Javle ; MD^¶ ; ; Gauri R. Varadhachary ; MD^¶ ; ; Robert A. Wolff ; MD^¶ ; ; Christopher H. Crane ; MD^&lowast ; ; Xuemei Wang ; MS^&dagger ; ; Howard Thames ; PhD^&lowast ; ; Sunil Krishnan ; MD^&lowast ; ; ^{skrishnan@mdanderson.org}
• 刊名：International Journal of Radiation Oncology*Biology*Physics
• 出版年：2017
• 出版时间：1 February 2017
• 年：2017
• 卷：97
• 期：2
• 页码：323-332
• 全文大小：376 K
• 卷排序：97

文摘

To determine whether severity of lymphopenia is dependent on radiation dose and fractional volume of spleen irradiated unintentionally during definitive chemoradiation (CRT) in patients with locally advanced pancreatic cancer (LAPC).Methods177 patients with LAPC received induction chemotherapy (mainly gemcitabine-based regimens) followed by CRT (median 50.4 Gy with concurrent capecitabine) from January 2006 to December 2012. Absolute lymphocyte count (ALC) was recorded at baseline, before CRT, and 2 to 10 weeks after CRT. Splenic dose-volume histogram (DVH) parameters were reported as mean splenic dose (MSD) and percentage of splenic volume receiving at least 5- (V5), 10- (V10), 15- (V15), and 20-Gy (V20) dose. Overall survival (OS) was analyzed with use of the Cox model, and development of post-CRT severe lymphopenia (ALC <0.5 K/UL) was assessed by multivariate logistic regression with use of baseline and treatment factors.ResultsThe median post-CRT ALC (0.68 K/UL; range, 0.13-2.72) was significantly lower than both baseline ALC (1.42 K/UL; range, 0.34-3.97; P<.0001) and pre-CRT ALC (1.32 K/UL, range 0.36-4.82; P<.0001). Post-CRT ALC <0.5 K/UL was associated with inferior OS on univariate analysis (median, 11.1 vs 15.3 months; P=.01) and multivariate analysis (hazard ratio = 1.66, P=.01). MSD (9.8 vs 6 Gy, P=.03), median V10 (32.6 vs 16%, P=.04), V15 (23.2 vs 9.5%, P=.03), and V20 (15.4 vs 4.6%, P=.02) were significantly higher in patients with severe lymphopenia than in those without. On multivariate analysis, postinduction lymphopenia (P<.001; odds ratio [OR] = 5.25) and MSD (P=.002; OR= 3.42) were independent predictors for the development of severe post-CRT lymphopenia.ConclusionSevere post-CRT lymphopenia is an independent predictor of poor OS in LAPC patients receiving CRT. Higher splenic doses increase the risk for the development of severe post-CRT lymphopenia. When clinically indicated, assessment of splenic DVHs before the acceptance of treatment plans may minimize the risk of severe post-CRT lymphopenia.