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Comparison of Toxicity Between Intensity Modulated Radiation Therapy and 3-Dimensional Conformal Radiation Therapy for Locally Advanced Non-Small Cell Lung Cancer
Poster Viewing Session E389
Volume 93 Number 3S Supplement 2015 Author Disclosure: E.H. Wang: None. C. Corso: None. C.E. Rutter: None. H.S. Park: None. A.B. Chen: None. A.W. Kim: None. L.D. Wilson: None. R.H. Decker: None. J.B. Yu: None.
2969 Treatment Plan Technique and Quality for Single Isocenter Stereotactic Ablative Radiation Therapy of Multiple Lung Lesions With Volumetric Modulated Arc Therapy or Intensity Modulated Radiosurgery K. Quan,1 K.M. Xu,1 Z.D. Horne,2 D.A. Clump, II,1 R. Lalonde,1 S.A. Burton,1 and D.E. Heron1; 1University of Pittsburgh Cancer Institute, Pittsburgh, PA, 2Department of Radiation Oncology, University of Pittsburgh Cancer Institute, Pittsburgh, PA Purpose/Objective(s): To provide a practical, systematic approach to the planning technique and evaluation of plan quality for the multi-lesion, single-isocenter stereotactic ablative radiation therapy (SABR) of the lung with volumetric modulated arc therapy (VMAT) or intensity-modulated radiosurgery (IMRS). Materials/Methods: Eleven patients with 2 or more lung lesions underwent single-isocenter VMAT or IMRS radiosurgery. All plans were normalized to the target maximum dose. For each plan, all targets were treated to the same dose. Plan conformity and dose gradient were maximized with dose control tuning structures surrounding targets. Conformity index (CI), homogeneity index (HI), gradient index (GI) and gradient distance (GD) were calculated for each plan. Results: One patient had 4 lesions and the remainder had 2 lesions. Six patients received VMAT and 5 patients received IMRS. For those treated with VMAT, two patients received 3-arc VMAT and four received 2-arc VMAT. For those treated with IMRS, two patients were treated with 10 and 11 beams, respectively, and the rest received 12 beams. Prescription doses ranged from 30 to 54 Gy in 3 to 5 fractions. The median prescribed isodose line was 84% (range: 80-86%). The median maximum dose was 57.1 Gy (range: 35.7-65.1 Gy). The mean combined PTV was 49.57 cm3 (range: 14.90 - 87.38 cm3). The mean minimum edge-to-edge and 3-dimensional distances between targets were 1.27 cm and 4.54 cm, respectively. The mean lung V20 was 6.72% (range: 1.71-20.45%). The mean lung V5 was 21.00% (range: 3.8-50.74%). The mean CI was 1.16 (range: 0.97-1.53). The mean HI was 1.21 (range: 1.16-1.28). The mean GI was 5.07 (range: 4.16-7.37). The mean GD was 1.65 cm (range: 1.14-2.69 cm). Conclusion: We report the very first single-isocenter IMRS plan for 4 lung lesions on 2 adjacent lobes. Compared to previous studies, our treatment plans use better techniques including individualizing and increasing the beam number in IMRS and applying half-arc VMAT with the isocenter placed outside the PTV. This multi-lesion, single-isocenter lung SABR planning technique demonstrated excellent plan quality and clinical efficiency and is recommended for radiosurgical treatment of 2 or more lung targets for well suited patients. Author Disclosure: K. Quan: None. K.M. Xu: None. Z.D. Horne: None. D.A. Clump: None. R. Lalonde: None. S.A. Burton: None. D.E. Heron: None.
2970 Comparison of Toxicity Between Intensity Modulated Radiation Therapy and 3-Dimensional Conformal Radiation Therapy for Locally Advanced Non-Small Cell Lung Cancer D.C. Ling,1 C.B. Hess,1 A.M. Chen,2 and M.E. Daly3; 1University of California, Davis, Sacramento, CA, 2University of California, Los Angeles, Los Angeles, CA, 3University of California, Davis Cancer Center, Sacramento, CA Purpose/Objective(s): Intensity-modulated radiation therapy (IMRT) is increasingly used for treatment of lung cancer. However, the ability of
IMRT to reduce toxicity is unclear, and often complicated by field selection differences. We compare acute toxicity and oncologic outcomes in a cohort of patients with stage III non-small cell lung cancer (NSCLC) treated with IMRT or 3D conformal radiation therapy (3DCRT), stratifying by use of elective nodal irradiation (ENI). Materials/Methods: We reviewed the charts of 145 consecutive patients with stage IIIA/B NSCLC treated with definitive chemoradiation. Sixtyfive (44.8%) underwent 3DCRT using ENI, 43 (30.0%) underwent 3DCRT using involved-field radiation therapy (IFRT), and 37 (25.5%) received IMRT with IFRT. All patients received concurrent chemotherapy. We compared grade 2 esophagitis and pneumonitis, hospitalizations, narcotic use, feeding tube placement, and percent weight loss by treatment technique and ENI. Local control and overall survival were analyzed with the Kaplan-Meier method. Results: We identified no significant difference in percent weight loss during treatment, incidence of hospitalization, grade 2 esophagitis or pneumonitis, or gastrostomy utilization by treatment technique or use of ENI. We observed a trend toward lower rates of grade 2 pneumonitis among IMRT patients compared to all 3DCRT patients (5.4% vs. 23.0%, pZ0.07). When stratified by fields, IMRT patients had a significantly lower rate of pneumonitis compared to 3DCRT-ENI patients (pZ0.03) but did not differ in pneumonitis rate with 3DCRT-IFRT patients (pZ0.44). 3DCRT-ENI plans were dosimetrically inferior, with a higher mean cardiac dose compared to IMRT (pZ0.007) and a trend toward higher cardiac dose compared to 3D-IFRT (pZ0.08). 3DCRT-ENI also resulted in a higher maximum spinal cord dose compared to both 3DCRT-IFRT (pZ0.0003) and IMRT (p<0.0001). Mean lung dose and lung V20 did not differ significantly between the 3 groups, and there were no statistically significant dosimetric differences between 3DCRT-IFRT and IMRT for lung, heart, spinal cord, or esophageal dose. Local control and overall survival were similar between cohorts. Conclusion: Acute and sub-acute toxicities were similar for patients treated with IMRT and with 3DCRT ENI, with a non-significant trend toward a reduction in pneumonitis with IMRT, but this difference appears to be largely driven by the use of ENI for a subset of 3DCRT cases. Consistent with prior studies, our data suggest IMRT provides non-inferior disease control and survival, but additional data are warranted to justify its routine use. Author Disclosure: D.C. Ling: None. C.B. Hess: None. A.M. Chen: None. M.E. Daly: None.
2971 Smoking Cessation Improves Survival After Stereotactic Body Radiation Therapy for Non-Small Cell Lung Carcinoma M.C. Roach,1 S. Rehman,1 T.A. DeWees,1 C.D. Abraham,2 J.D. Bradley,3 and C.G. Robinson1; 1Washington University School of Medicine, St. Louis, MO, 2Washington University, St. Louis, MO, 3Center for Advanced Medicine, Saint Louis, MO Purpose/Objective(s): Many patients continue to smoke tobacco even after being diagnosed and treated for non-small cell lung cancer (NSCLC). As stereotactic body radiation therapy (SBRT) is a quick, effective, and well-tolerated treatment for NSCLC, it can be difficult to convince these patients to quit smoking in follow-up. We evaluated whether there was a survival benefit to smoking cessation after SBRT. Materials/Methods: A total of 119 patients who were still smoking tobacco at the time of SBRT were identified from a prospective institutional review board approved registry, in which all patients consented for inclusion pre-treatment. All patients had AJCC stage I-II NSCLC and were treated with definitive intent. Peripheral tumors were treated to 54 or 60 Gy in 3 fractions and central tumors to 50 Gy in 5 fractions. Patients were reviewed for overall survival (OS) and disease progression calculated from completion of therapy. The log-rank test and Cox regression were used to identify factors predictive of OS.
Volume 93 Number 3S Supplement 2015 Author Disclosure: E.H. Wang: None. C. Corso: None. C.E. Rutter: None. H.S. Park: None. A.B. Chen: None. A.W. Kim: None. L.D. Wilson: None. R.H. Decker: None. J.B. Yu: None.
2969 Treatment Plan Technique and Quality for Single Isocenter Stereotactic Ablative Radiation Therapy of Multiple Lung Lesions With Volumetric Modulated Arc Therapy or Intensity Modulated Radiosurgery K. Quan,1 K.M. Xu,1 Z.D. Horne,2 D.A. Clump, II,1 R. Lalonde,1 S.A. Burton,1 and D.E. Heron1; 1University of Pittsburgh Cancer Institute, Pittsburgh, PA, 2Department of Radiation Oncology, University of Pittsburgh Cancer Institute, Pittsburgh, PA Purpose/Objective(s): To provide a practical, systematic approach to the planning technique and evaluation of plan quality for the multi-lesion, single-isocenter stereotactic ablative radiation therapy (SABR) of the lung with volumetric modulated arc therapy (VMAT) or intensity-modulated radiosurgery (IMRS). Materials/Methods: Eleven patients with 2 or more lung lesions underwent single-isocenter VMAT or IMRS radiosurgery. All plans were normalized to the target maximum dose. For each plan, all targets were treated to the same dose. Plan conformity and dose gradient were maximized with dose control tuning structures surrounding targets. Conformity index (CI), homogeneity index (HI), gradient index (GI) and gradient distance (GD) were calculated for each plan. Results: One patient had 4 lesions and the remainder had 2 lesions. Six patients received VMAT and 5 patients received IMRS. For those treated with VMAT, two patients received 3-arc VMAT and four received 2-arc VMAT. For those treated with IMRS, two patients were treated with 10 and 11 beams, respectively, and the rest received 12 beams. Prescription doses ranged from 30 to 54 Gy in 3 to 5 fractions. The median prescribed isodose line was 84% (range: 80-86%). The median maximum dose was 57.1 Gy (range: 35.7-65.1 Gy). The mean combined PTV was 49.57 cm3 (range: 14.90 - 87.38 cm3). The mean minimum edge-to-edge and 3-dimensional distances between targets were 1.27 cm and 4.54 cm, respectively. The mean lung V20 was 6.72% (range: 1.71-20.45%). The mean lung V5 was 21.00% (range: 3.8-50.74%). The mean CI was 1.16 (range: 0.97-1.53). The mean HI was 1.21 (range: 1.16-1.28). The mean GI was 5.07 (range: 4.16-7.37). The mean GD was 1.65 cm (range: 1.14-2.69 cm). Conclusion: We report the very first single-isocenter IMRS plan for 4 lung lesions on 2 adjacent lobes. Compared to previous studies, our treatment plans use better techniques including individualizing and increasing the beam number in IMRS and applying half-arc VMAT with the isocenter placed outside the PTV. This multi-lesion, single-isocenter lung SABR planning technique demonstrated excellent plan quality and clinical efficiency and is recommended for radiosurgical treatment of 2 or more lung targets for well suited patients. Author Disclosure: K. Quan: None. K.M. Xu: None. Z.D. Horne: None. D.A. Clump: None. R. Lalonde: None. S.A. Burton: None. D.E. Heron: None.
2970 Comparison of Toxicity Between Intensity Modulated Radiation Therapy and 3-Dimensional Conformal Radiation Therapy for Locally Advanced Non-Small Cell Lung Cancer D.C. Ling,1 C.B. Hess,1 A.M. Chen,2 and M.E. Daly3; 1University of California, Davis, Sacramento, CA, 2University of California, Los Angeles, Los Angeles, CA, 3University of California, Davis Cancer Center, Sacramento, CA Purpose/Objective(s): Intensity-modulated radiation therapy (IMRT) is increasingly used for treatment of lung cancer. However, the ability of
IMRT to reduce toxicity is unclear, and often complicated by field selection differences. We compare acute toxicity and oncologic outcomes in a cohort of patients with stage III non-small cell lung cancer (NSCLC) treated with IMRT or 3D conformal radiation therapy (3DCRT), stratifying by use of elective nodal irradiation (ENI). Materials/Methods: We reviewed the charts of 145 consecutive patients with stage IIIA/B NSCLC treated with definitive chemoradiation. Sixtyfive (44.8%) underwent 3DCRT using ENI, 43 (30.0%) underwent 3DCRT using involved-field radiation therapy (IFRT), and 37 (25.5%) received IMRT with IFRT. All patients received concurrent chemotherapy. We compared grade 2 esophagitis and pneumonitis, hospitalizations, narcotic use, feeding tube placement, and percent weight loss by treatment technique and ENI. Local control and overall survival were analyzed with the Kaplan-Meier method. Results: We identified no significant difference in percent weight loss during treatment, incidence of hospitalization, grade 2 esophagitis or pneumonitis, or gastrostomy utilization by treatment technique or use of ENI. We observed a trend toward lower rates of grade 2 pneumonitis among IMRT patients compared to all 3DCRT patients (5.4% vs. 23.0%, pZ0.07). When stratified by fields, IMRT patients had a significantly lower rate of pneumonitis compared to 3DCRT-ENI patients (pZ0.03) but did not differ in pneumonitis rate with 3DCRT-IFRT patients (pZ0.44). 3DCRT-ENI plans were dosimetrically inferior, with a higher mean cardiac dose compared to IMRT (pZ0.007) and a trend toward higher cardiac dose compared to 3D-IFRT (pZ0.08). 3DCRT-ENI also resulted in a higher maximum spinal cord dose compared to both 3DCRT-IFRT (pZ0.0003) and IMRT (p<0.0001). Mean lung dose and lung V20 did not differ significantly between the 3 groups, and there were no statistically significant dosimetric differences between 3DCRT-IFRT and IMRT for lung, heart, spinal cord, or esophageal dose. Local control and overall survival were similar between cohorts. Conclusion: Acute and sub-acute toxicities were similar for patients treated with IMRT and with 3DCRT ENI, with a non-significant trend toward a reduction in pneumonitis with IMRT, but this difference appears to be largely driven by the use of ENI for a subset of 3DCRT cases. Consistent with prior studies, our data suggest IMRT provides non-inferior disease control and survival, but additional data are warranted to justify its routine use. Author Disclosure: D.C. Ling: None. C.B. Hess: None. A.M. Chen: None. M.E. Daly: None.
2971 Smoking Cessation Improves Survival After Stereotactic Body Radiation Therapy for Non-Small Cell Lung Carcinoma M.C. Roach,1 S. Rehman,1 T.A. DeWees,1 C.D. Abraham,2 J.D. Bradley,3 and C.G. Robinson1; 1Washington University School of Medicine, St. Louis, MO, 2Washington University, St. Louis, MO, 3Center for Advanced Medicine, Saint Louis, MO Purpose/Objective(s): Many patients continue to smoke tobacco even after being diagnosed and treated for non-small cell lung cancer (NSCLC). As stereotactic body radiation therapy (SBRT) is a quick, effective, and well-tolerated treatment for NSCLC, it can be difficult to convince these patients to quit smoking in follow-up. We evaluated whether there was a survival benefit to smoking cessation after SBRT. Materials/Methods: A total of 119 patients who were still smoking tobacco at the time of SBRT were identified from a prospective institutional review board approved registry, in which all patients consented for inclusion pre-treatment. All patients had AJCC stage I-II NSCLC and were treated with definitive intent. Peripheral tumors were treated to 54 or 60 Gy in 3 fractions and central tumors to 50 Gy in 5 fractions. Patients were reviewed for overall survival (OS) and disease progression calculated from completion of therapy. The log-rank test and Cox regression were used to identify factors predictive of OS.