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Analysis of Dose-Volume Metrics Associated with Radiation Pneumonitis after Stereotactic Body Radiotherapy for Lung Cancer
I. J. Radiation Oncology d Biology d Physics
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Volume 78, Number 3, Supplement, 2010
surgery prior to RT. Nine patients were treated for palliative intent due to distant metastasis at the time of radiotherapy. Treatment outcome including survival, local and distant control and toxicity were analyzed. Results: The median follow-up was 44 month (range 3 to 109 month). Overall 1-year, 3-year and 5-year survival rates were 95%, 87%, and 69%, respectively. Twenty-five patients (21.5%) developed a histologically proven local recurrence after radiation. For local control three groups were analyzed: Group A underwent complete tumor resection (R0/R1) and all (50 patients) received photon IMRT only, resulting in 1-year, 3-year and 5-year lc rates of 98%, 90%, and 82%. Group B (36 patients) had at least gross residual tumor (R2 or no surgery) and were treated with a combination of photon IMRT and carbon ion boost, while group C (30 patients) had also at least residual disease but was treated with IMRT alone. Local 1-year, 3-year, and 5-year control rates were 97%, 88%, 71%, and 100%, 72%, 56%, respectively in favor of the carbon ion boost concept. Only in a few patients acute or late toxicity . Grade 2 was seen. Conclusions: Photon IMRT is an effective treatment option for ACC in the R0/1 situation after surgery. The combination of photon IMRT with carbon ion boost is advantageous vs. photon IMRT alone with respect to local control in patients with gross residual tumor or patients not undergoing surgery. Author Disclosure: S. Paro, None; C. Timke, None; F. Roeder, None; A. Jensen, None; P. Hegenbarth, None; M. Muenter, None; D. Schultz-Ertner, None; J. Debus, None; P.E. Huber, None.
1084
Analysis of Dose-Volume Metrics Associated with Radiation Pneumonitis after Stereotactic Body Radiotherapy for Lung Cancer
Y. Matsuo, K. Shibuya, M. Narabayashi, K. Sakanaka, M. Nakamura, T. Mizowaki, M. Hiraoka Kyoto University Graduate School of Medicine, Kyoto, Japan Purpose/Objective(s): The objective was to find dose-volume factors associated with radiation pneumonitis (RP) after stereotactic body radiotherapy (SBRT) for lung cancer. Materials/Methods: Seventy-four patients who underwent SBRT for primary lung cancer were analyzed in the present study. Fifty-five were male, and nineteen were female. A median of age was 77 years old (range, 63-88). Chemotherapy was not administered unless disease progression was confirmed. Prescription dose for SBRT was uniformly 48 Gy in 4 fractions at the isocenter. Irradiation was performed with 6-MV X-ray beams, which were shaped into the planning target volume (PTV) plus 5-mm margins, from a linear accelerator (Clinac 2300 C/D; Varian). Dose distribution was re-calculated with the analytical anisotropic algorithm in Eclipse (Varian). RP was graded according to the CTCAE version 3, and high-grade RP was herein defined as Grade 2 or worse. Optimal cut points dividing the patient population into two subgroups based on incidence of high-grade RP were searched using the recursive partitioning method in the following dose-volume metrics: PTV volume (cc), mean lung dose (Gy), V5, V10, V15, V20, V25, V30, V35, and V40, where Vd was defined as a relative volume (%) of the lung other than PTV which received more than a threshold dose d Gy. Results: RP Grade 2 or worse was observed in 15 patients (20.2%), including 1 patient of Grade 3, with a median follow-up duration of 31 months. Optimal cut points for pulmonary doses were found in V25 and V20. These factors were highly correlated with each other (R = 0.99), and V25 was more significant than V20. High-grade RP rate was 14.8% in the patients with V25 less than 4.2%, while the rate was 46.2% in the remainder (p = 0.02). PTV volume was found as the other significant factor. High-grade RP rate was significantly lower in the group with PTV volume less than 37.7 cc compared with the larger PTV group (11.1% vs. 34.5%, p = 0.02). Correlation between lung V25 and PTV volume was not strong (R = 0.58). When dividing the patient population into three subgroups: (1) PTV\37.7 cc; (2) PTV $ 37.7 cc and V25\4.2%; and (3) PTV $ 37.7 cc and V25 $ 4.2%, incidence rates of high-grade RP were 11.1%, 23.5%, and 50.0%, respectively (p = 0.01). Conclusions: Lung V25 and PTV volume were suggested as significant factors associated with RP after SBRT. Author Disclosure: Y. Matsuo, None; K. Shibuya, None; M. Narabayashi, None; K. Sakanaka, None; M. Nakamura, None; T. Mizowaki, None; M. Hiraoka, None.
1085
The Impact of Introducing Stereotactic Body Radiotherapy in Elderly Patients with Stage I NSCLC: A Population-Based Time-Trend Analysis
D. Palma1, O. Visser2, F. Lagerwaard1, J. Belderbos3, B. Slotman1, S. Senan1 1 3
VU University Medical Center, Amsterdam, Netherlands, 2Comprehensive Cancer Centre, Amsterdam, Netherlands, Netherlands Cancer Institute, Amsterdam, Netherlands
Purpose/Objective(s): Treatment options for elderly patients with stage I NSCLC have improved greatly in the past decade, largely due to the introduction of stereotactic body radiotherapy (SBRT). The benefits of SBRT have not yet been assessed in randomized controlled trials. In the absence of such trials, population-based data provides the highest level of evidence. Materials/Methods: We studied treatment patterns and overall survival (OS) in patients aged 75 or older with stage I NSCLC, using a comprehensive population-based registry in North Holland (http://www.ikcnet.nl/IKA) that covers 2.9 million people and captures demographic details, treatments and outcomes. Data was assessed for three eras after the regional introduction of routine FDG-PET scanning: 1999-2001 (period A, pre-SBRT); 2002-04 (period B, some availability of SBRT) and 2005-07 (period C, full access to SBRT). Chi-square, Kaplan-Meier and Cox Regression were used to compare treatment patterns and OS between these periods. Outcomes were assessed for 3 treatment groups: surgery, radiotherapy (RT), or neither. Results: Eight hundred seventy-five elderly patients were diagnosed with stage I NSCLC in the study period. Median follow-up was 54 months. Primary treatment was surgery in 299 (34%), RT in 299 (34%) and neither in 277 (32%). The proportion of RT patients receiving SBRT was 23% in period B and 55% in period C. The proportion of patients undergoing RT increased significantly (26% in period A vs. 42% in period C; p \ 0.01), which corresponded to decreases in patients receiving no treatment (38% vs. 26%, respectively) and surgery (36% vs. 32%, respectively). Thirty-day mortality after surgery was 7.4%, and after SBRT was 1%. Median survival for all patients increased from 16 months in periods A and B to 21 months in period C. On multivariate analysis, factors predictive of improved OS were T1 disease (vs. T2, HR 0.55; 95% CI, 0.45-0.67), pathological confirmation of disease
S178
Volume 78, Number 3, Supplement, 2010
surgery prior to RT. Nine patients were treated for palliative intent due to distant metastasis at the time of radiotherapy. Treatment outcome including survival, local and distant control and toxicity were analyzed. Results: The median follow-up was 44 month (range 3 to 109 month). Overall 1-year, 3-year and 5-year survival rates were 95%, 87%, and 69%, respectively. Twenty-five patients (21.5%) developed a histologically proven local recurrence after radiation. For local control three groups were analyzed: Group A underwent complete tumor resection (R0/R1) and all (50 patients) received photon IMRT only, resulting in 1-year, 3-year and 5-year lc rates of 98%, 90%, and 82%. Group B (36 patients) had at least gross residual tumor (R2 or no surgery) and were treated with a combination of photon IMRT and carbon ion boost, while group C (30 patients) had also at least residual disease but was treated with IMRT alone. Local 1-year, 3-year, and 5-year control rates were 97%, 88%, 71%, and 100%, 72%, 56%, respectively in favor of the carbon ion boost concept. Only in a few patients acute or late toxicity . Grade 2 was seen. Conclusions: Photon IMRT is an effective treatment option for ACC in the R0/1 situation after surgery. The combination of photon IMRT with carbon ion boost is advantageous vs. photon IMRT alone with respect to local control in patients with gross residual tumor or patients not undergoing surgery. Author Disclosure: S. Paro, None; C. Timke, None; F. Roeder, None; A. Jensen, None; P. Hegenbarth, None; M. Muenter, None; D. Schultz-Ertner, None; J. Debus, None; P.E. Huber, None.
1084
Analysis of Dose-Volume Metrics Associated with Radiation Pneumonitis after Stereotactic Body Radiotherapy for Lung Cancer
Y. Matsuo, K. Shibuya, M. Narabayashi, K. Sakanaka, M. Nakamura, T. Mizowaki, M. Hiraoka Kyoto University Graduate School of Medicine, Kyoto, Japan Purpose/Objective(s): The objective was to find dose-volume factors associated with radiation pneumonitis (RP) after stereotactic body radiotherapy (SBRT) for lung cancer. Materials/Methods: Seventy-four patients who underwent SBRT for primary lung cancer were analyzed in the present study. Fifty-five were male, and nineteen were female. A median of age was 77 years old (range, 63-88). Chemotherapy was not administered unless disease progression was confirmed. Prescription dose for SBRT was uniformly 48 Gy in 4 fractions at the isocenter. Irradiation was performed with 6-MV X-ray beams, which were shaped into the planning target volume (PTV) plus 5-mm margins, from a linear accelerator (Clinac 2300 C/D; Varian). Dose distribution was re-calculated with the analytical anisotropic algorithm in Eclipse (Varian). RP was graded according to the CTCAE version 3, and high-grade RP was herein defined as Grade 2 or worse. Optimal cut points dividing the patient population into two subgroups based on incidence of high-grade RP were searched using the recursive partitioning method in the following dose-volume metrics: PTV volume (cc), mean lung dose (Gy), V5, V10, V15, V20, V25, V30, V35, and V40, where Vd was defined as a relative volume (%) of the lung other than PTV which received more than a threshold dose d Gy. Results: RP Grade 2 or worse was observed in 15 patients (20.2%), including 1 patient of Grade 3, with a median follow-up duration of 31 months. Optimal cut points for pulmonary doses were found in V25 and V20. These factors were highly correlated with each other (R = 0.99), and V25 was more significant than V20. High-grade RP rate was 14.8% in the patients with V25 less than 4.2%, while the rate was 46.2% in the remainder (p = 0.02). PTV volume was found as the other significant factor. High-grade RP rate was significantly lower in the group with PTV volume less than 37.7 cc compared with the larger PTV group (11.1% vs. 34.5%, p = 0.02). Correlation between lung V25 and PTV volume was not strong (R = 0.58). When dividing the patient population into three subgroups: (1) PTV\37.7 cc; (2) PTV $ 37.7 cc and V25\4.2%; and (3) PTV $ 37.7 cc and V25 $ 4.2%, incidence rates of high-grade RP were 11.1%, 23.5%, and 50.0%, respectively (p = 0.01). Conclusions: Lung V25 and PTV volume were suggested as significant factors associated with RP after SBRT. Author Disclosure: Y. Matsuo, None; K. Shibuya, None; M. Narabayashi, None; K. Sakanaka, None; M. Nakamura, None; T. Mizowaki, None; M. Hiraoka, None.
1085
The Impact of Introducing Stereotactic Body Radiotherapy in Elderly Patients with Stage I NSCLC: A Population-Based Time-Trend Analysis
D. Palma1, O. Visser2, F. Lagerwaard1, J. Belderbos3, B. Slotman1, S. Senan1 1 3
VU University Medical Center, Amsterdam, Netherlands, 2Comprehensive Cancer Centre, Amsterdam, Netherlands, Netherlands Cancer Institute, Amsterdam, Netherlands
Purpose/Objective(s): Treatment options for elderly patients with stage I NSCLC have improved greatly in the past decade, largely due to the introduction of stereotactic body radiotherapy (SBRT). The benefits of SBRT have not yet been assessed in randomized controlled trials. In the absence of such trials, population-based data provides the highest level of evidence. Materials/Methods: We studied treatment patterns and overall survival (OS) in patients aged 75 or older with stage I NSCLC, using a comprehensive population-based registry in North Holland (http://www.ikcnet.nl/IKA) that covers 2.9 million people and captures demographic details, treatments and outcomes. Data was assessed for three eras after the regional introduction of routine FDG-PET scanning: 1999-2001 (period A, pre-SBRT); 2002-04 (period B, some availability of SBRT) and 2005-07 (period C, full access to SBRT). Chi-square, Kaplan-Meier and Cox Regression were used to compare treatment patterns and OS between these periods. Outcomes were assessed for 3 treatment groups: surgery, radiotherapy (RT), or neither. Results: Eight hundred seventy-five elderly patients were diagnosed with stage I NSCLC in the study period. Median follow-up was 54 months. Primary treatment was surgery in 299 (34%), RT in 299 (34%) and neither in 277 (32%). The proportion of RT patients receiving SBRT was 23% in period B and 55% in period C. The proportion of patients undergoing RT increased significantly (26% in period A vs. 42% in period C; p \ 0.01), which corresponded to decreases in patients receiving no treatment (38% vs. 26%, respectively) and surgery (36% vs. 32%, respectively). Thirty-day mortality after surgery was 7.4%, and after SBRT was 1%. Median survival for all patients increased from 16 months in periods A and B to 21 months in period C. On multivariate analysis, factors predictive of improved OS were T1 disease (vs. T2, HR 0.55; 95% CI, 0.45-0.67), pathological confirmation of disease