Lymphocyte Depletion by Radiation Therapy Alone Is Associated With Poor Survival in Non-Small Cell Lung Cancer

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International Journal of Radiation Oncology  Biology  Physics

Cox proportional hazards model was used to assess covariates associated with locoregional or distant failure. Results: A total of 167 patients were identified. Median age was 66 (range 45-86) and the median follow-up was 15.4 months (range 1-128). The majority of patients were male (54%), had stage IIIA disease (58%), and did not receive additional chemotherapy (65%). There were a total of 37 (22%) locoregional and 74 (44%) distant failures. The median time to treatment failure was 13.5 months (95% CI 9-17.6). The 2-year local relapse free survival was 69% and distant relapse free survival was 50.1%. Univariate analysis a trend towards improved locoregional control in patients receiving IMRT vs 3D-CRT (HR 0.55, 95% CI 0.29-1.07, PZ0.077). On multivariate analysis, IMRT use (HR 0.27, 95% CI 0.100.73, PZ0.010) and stage IIIA disease (HR 0.35 95% CI 0.15-0.85 PZ0.020) were associated with improved locoregional control. Lower rates of distant recurrence were observed in univariate analysis of patients treated with >64 Gy (HR 0.63, 95% CI 0.40-1.00, PZ0.049) or adjuvant chemotherapy (HR 0.51, 95% CI 0.28-0.92, 0.025). On multivariate analysis, receipt of adjuvant chemotherapy was the only covariate associated with a decreased risk of distant failure (HR 0.42, 95% CI 0.22-0.78, PZ0.006). There was no association between radiation dose, smoking history, histology, chemotherapy regimen, or other factor with locoregional or distant recurrence. Conclusion: Recurrence rates remain high in patients with locally advanced NSCLC. However, the use of IMRT and adjuvant chemotherapy correlated with decrease risks of locoregional and distant failure, respectively, in appropriately selected patients. Further research is warranted to confirm these findings. Author Disclosure: S. Yoon: None. T. Shaikh: None. E.A. Ross: None. J. Bauman: None. H. Borghaei: None. R. Mehra: None. J.E. Meyer: None. M.A. Hallman: Consultant; New Century Health.

survival (OS) was 33 months, 79%, 68%, and 48%, respectively. There was no significant difference in OS among patients with metastatic disease confined to the lung versus patients with additional extrathoracic oligometastatic disease (OS 37 vs 25 months, respectively; pZ0.093). Primary disease site was not associated with disease outcome. Local failure occurred in 8/111 lesions for a 2-year local control rate of 85%. Grade 3 pneumonitis was reported in two (2%) of patients. There was no grade 4-5 toxicity. Conclusion: This is one of the largest experiences with lung SBRT for metastatic disease. Lung SBRT provides excellent local control with acceptable toxicity. Properly selected oligometastatic patients have excellent long-term survival with the addition of SBRT into their management. Patients with oligometastatic disease confined to the lung do especially well, while patients with extrathoracic disease progress rapidly. These findings provide guidance for optimal patient selection and counseling. Author Disclosure: R. Fega: None. U. Goyal: None. H. Ross: None. D. Jaroszewski: None. H. Paripati: None. H. Kosiorek: None. T.B. Daniels: None. S.E. Schild: None. W.G. Rule: None. S.A. Vora: None. J.B. Ashman: None.

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Purpose/Objective(s): Severe posttreatment lymphopenia has been reported in advanced stage non-small cell lung cancer (NSCLC), after concurrent chemoradiation, and it was associated with reduced survival. However, these previous studies including other sites all came from patients who received chemotherapy, concurrently with radiation therapy (RT). Current study, we evaluated the serial weekly lymphocyte counts change during RT alone for NSCLC. We also attempt to investigate its prognostic role. Materials/Methods: Between 2002 and 2010, 83 patients with stage II-III NSCLC received RT alone at a dose of over 60 Gy. Absolute blood lymphocyte counts and their relative percentage in total WBC counts were obtained from CBC tests performed prior to and weekly during RT. Results: Based on the trend of changes in WBCs, laboratory values at preRT, second week (day 14w20), and fourth week (28w34) were analyzed for its association with prognosis. High pre-RT ALC (> 1800 cells/mL) was related to both better OS and PFS (13.6 vs. 5.6 months and 20.3 vs. 10.4 months). During RT, ALCs at 2nd week (W2-ALC) was significant factor for both OS and PFS. Median OS and PFS for patients in the high W2-ALC (> 900 cells/mL) was 18.9 and 12.5 months versus 15.3 and 5.9 months for patients in the low W2-ALC (900 cells/mL) group (PZ0.035 and PZ0.053, respectively). In addition to absolute count, rapid change of lymphocyte was also significant poor prognostic factor. W2-ALC divided by pre-RT ALC was defined as W2-ALC ratio. The median OS and PFS of patients with W2-ALC ratio  0.3 was significantly lower than that of patients with W2-ALC ratio > 0.3 (5.9 vs. 17.8 months and 4.8 vs. 10.4 months). For pattern of failure analysis, pre-RT ALC (1800 cells/mL) and pre-RT LNR ( 0.5) were related to distant metastasis. Conclusion: The lymphocyte count at 2 week was a strong predictor of both progression and survival. Not only the absolute number, the degree of change was also a significant prognostic factor. The reason for poor prognosis of lower lymphocyte group seemed to be related to distant metastasis. Author Disclosure: J. Joo: None. S. Song: None. J. Park: None. E. Choi: None. S. Jeong: None. W. Choi: None.

Patients With Oligometastatic Disease Limited to the Chest Are Optimal Candidates for Lung Stereotactic Body Radiation Therapy R. Fega,1 U. Goyal,2 H. Ross,1 D. Jaroszewski,1 H. Paripati,1 H. Kosiorek,1 T.B. Daniels,3 S.E. Schild,1 W.G. Rule,1 S.A. Vora,1 and J.B. Ashman1; 1 Mayo Clinic, Phoenix, AZ, 2University of Arizona, Tucson, AZ, 3Mayo Clinic Arizona, Phoenix, AZ Purpose/Objective(s): The aim of this study was to identify patients with pulmonary metastases who would be most likely to benefit from lung stereotactic body radiation therapy (SBRT). Materials/Methods: After institutional review board approval, we retrospectively identified 92 patients with 111 pulmonary metastases from any primary site treated with SBRT at our institution between 2008 and 2015. Gross tumor volume (GTV) was non-uniformly expanded to create an internal target volume (ITV) to encompass tumor motion. A 5 mm uniform expansion of the ITV was applied to create the planning target volume (PTV). Cone beam CT was used for daily image-guidance. The most common SBRT regimen was 48 Gy/4 fractions for peripheral lesions, and 50 Gy/5 fractions for central lesions. Toxicities were recorded according to the Common Terminology Criteria for Adverse Events (CTCAE) Version 4.0. Survival curves were calculated from the time of SBRT using the Kaplan-Meier method. Results: The median follow-up was 17 months (range: 3-74 months). Median PTV was 29 cm3. There were 51 men and 41 women included, with a median age of 70 years (range: 37-90). The most common primary tumors were lung (nZ30), colorectal (nZ14), melanoma (nZ13), and head and neck (nZ12). 44 patients had solitary lung lesions, 31 patients had >1 lung lesions with no extrathoracic disease, and 17 patients had additional sites of oligometastatic disease outside of the thorax. Median time to next treatment event was 18 months in patients with metastatic disease confined to the lungs versus 5 months with extrathoracic oligometastatic disease present (pZ0.01). For patients with a solitary lesion, time to next treatment was 28 months. The median, 1, 2, and 3 year

3177 Lymphocyte Depletion by Radiation Therapy Alone Is Associated With Poor Survival in Non-Small Cell Lung Cancer J.H. Joo,1 S.Y. Song,2 J. Park,3 E.K. Choi,1 S.Y. Jeong,2 and W. Choi4; 1 Asan Medical Center, Seoul, South Korea, 2Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea, 3Asan Medical Center, Seoul, Korea, The Republic of Korea, 4Gangneung Asan Hospital, University of Ulsan College of Medicine, Gangneung, South Korea