International Journal of
Radiation Oncology biology
physics
www.redjournal.org
Clinical Investigation: Thoracic Cancer
Association Between White Blood Cell Count Following Radiation Therapy With Radiation Pneumonitis in Non-Small Cell Lung Cancer Chad Tang, MD, MS,* Daniel R. Gomez, MD,* Hongmei Wang, MD,*,z Lawrence B. Levy, MS,* Yan Zhuang, MD,*,y Ting Xu, MD,* Quynh Nguyen, MD,* Ritsuko Komaki, MD,* and Zhongxing Liao, MD* Departments of *Radiation Oncology and yRadiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas; and zDepartment of Radiation Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, China Received Jun 20, 2013, and in revised form Oct 3, 2013. Accepted for publication Oct 22, 2013.
Summary Radiation pneumonitis (RP) represents an inflammatory response to radiation. We present evidence that higher postradiation white blood cell count is associated with RP in 366 patients receiving definitive radiation for nonsmall cell lung cancer. Multivariate analysis revealed the discriminative utility of this marker to be independent of established factors. Postradiation white blood cell count may serve as a readily available clinical marker to predict and/or diagnose RP.
Purpose: Radiation pneumonitis (RP) is an inflammatory response to radiation therapy (RT). We assessed the association between RP and white blood cell (WBC) count, an established metric of systemic inflammation, after RT for non-small cell lung cancer. Methods and Materials: We retrospectively analyzed 366 patients with non-small cell lung cancer who received 60 Gy as definitive therapy. The primary endpoint was whether WBC count after RT (defined as 2 weeks through 3 months after RT completion) was associated with grade 3 or grade 2 RP. Median lung volume receiving 20 Gy (V20) was 31%, and post-RT WBC counts ranged from 1.7 to 21.2 103 WBCs/mL. Odds ratios (ORs) associating clinical variables and post-RT WBC counts with RP were calculated via logistic regression. A recursivepartitioning algorithm was used to define optimal post-RT WBC count cut points. Results: Post-RT WBC counts were significantly higher in patients with grade 3 RP than without (P1 primary lung tumor; (3) previous receipt of thoracic radiation; (4) treatment with stereotactic ablative RT; (5) missing dosimetry data; and (6) lack of computed tomography or positron emission tomography scans within 1 year of RT completion because RP diagnosis required meeting imaging criteria.
Follow-up Follow-up visits during which patients underwent interval history and physical examinations were conducted at least once before RT and weekly during RT. After RT completion, patients returned within the first 1 to 3 months and then every 3 to 4 months thereafter for the first 2 to 3 years, twice a year until 5 years, and yearly thereafter. Systemic WBC counts were measured via peripheral venous access using standard phlebotomy techniques at the discretion of the treating physician. RP was diagnosed on the basis of clinical symptoms and the presence of any of the following radiographic
Patient characteristics Baseline and treatment characteristics of the 366 patients who met study criteria are displayed in Table 1. Most patients were male with pretreatment Karnofsky performance status scores of 70 or 80 and a median age 66 years at diagnosis. Most cancers were of Table 1
Baseline patient and treatment characteristics Characteristics
Sex Male Female Age at diagnosis (y) Patients receiving steroids (oral or intravenous) Radiation dose to gross tumor volume (Gy or Gy[RBE]) Gross tumor volume (cm3) Mean lung dose (Gy) Lung V20 (%) Karnofsky performance status score
Radiation Oncology biology
physics
www.redjournal.org
Clinical Investigation: Thoracic Cancer
Association Between White Blood Cell Count Following Radiation Therapy With Radiation Pneumonitis in Non-Small Cell Lung Cancer Chad Tang, MD, MS,* Daniel R. Gomez, MD,* Hongmei Wang, MD,*,z Lawrence B. Levy, MS,* Yan Zhuang, MD,*,y Ting Xu, MD,* Quynh Nguyen, MD,* Ritsuko Komaki, MD,* and Zhongxing Liao, MD* Departments of *Radiation Oncology and yRadiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas; and zDepartment of Radiation Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, China Received Jun 20, 2013, and in revised form Oct 3, 2013. Accepted for publication Oct 22, 2013.
Summary Radiation pneumonitis (RP) represents an inflammatory response to radiation. We present evidence that higher postradiation white blood cell count is associated with RP in 366 patients receiving definitive radiation for nonsmall cell lung cancer. Multivariate analysis revealed the discriminative utility of this marker to be independent of established factors. Postradiation white blood cell count may serve as a readily available clinical marker to predict and/or diagnose RP.
Purpose: Radiation pneumonitis (RP) is an inflammatory response to radiation therapy (RT). We assessed the association between RP and white blood cell (WBC) count, an established metric of systemic inflammation, after RT for non-small cell lung cancer. Methods and Materials: We retrospectively analyzed 366 patients with non-small cell lung cancer who received 60 Gy as definitive therapy. The primary endpoint was whether WBC count after RT (defined as 2 weeks through 3 months after RT completion) was associated with grade 3 or grade 2 RP. Median lung volume receiving 20 Gy (V20) was 31%, and post-RT WBC counts ranged from 1.7 to 21.2 103 WBCs/mL. Odds ratios (ORs) associating clinical variables and post-RT WBC counts with RP were calculated via logistic regression. A recursivepartitioning algorithm was used to define optimal post-RT WBC count cut points. Results: Post-RT WBC counts were significantly higher in patients with grade 3 RP than without (P1 primary lung tumor; (3) previous receipt of thoracic radiation; (4) treatment with stereotactic ablative RT; (5) missing dosimetry data; and (6) lack of computed tomography or positron emission tomography scans within 1 year of RT completion because RP diagnosis required meeting imaging criteria.
Follow-up Follow-up visits during which patients underwent interval history and physical examinations were conducted at least once before RT and weekly during RT. After RT completion, patients returned within the first 1 to 3 months and then every 3 to 4 months thereafter for the first 2 to 3 years, twice a year until 5 years, and yearly thereafter. Systemic WBC counts were measured via peripheral venous access using standard phlebotomy techniques at the discretion of the treating physician. RP was diagnosed on the basis of clinical symptoms and the presence of any of the following radiographic
Patient characteristics Baseline and treatment characteristics of the 366 patients who met study criteria are displayed in Table 1. Most patients were male with pretreatment Karnofsky performance status scores of 70 or 80 and a median age 66 years at diagnosis. Most cancers were of Table 1
Baseline patient and treatment characteristics Characteristics
Sex Male Female Age at diagnosis (y) Patients receiving steroids (oral or intravenous) Radiation dose to gross tumor volume (Gy or Gy[RBE]) Gross tumor volume (cm3) Mean lung dose (Gy) Lung V20 (%) Karnofsky performance status score
