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Dosimetric evaluation of SBRT treatment plans of non-central lung tumours: clinical experience

Published online by Cambridge University Press:  09 December 2020

Ernest Osei*
Affiliation:
Department of Medical Physics, Grand River Regional Cancer Centre, Kitchener, ON, Canada Department of Physics and Astronomy, University of Waterloo, Waterloo, ON, Canada Department of Systems Design Engineering, University of Waterloo, Waterloo, ON, Canada Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, ONCanada
Johnson Darko
Affiliation:
Department of Medical Physics, Grand River Regional Cancer Centre, Kitchener, ON, Canada Department of Physics and Astronomy, University of Waterloo, Waterloo, ON, Canada Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, ONCanada
Steph Swanson
Affiliation:
Department of Physics and Astronomy, University of Waterloo, Waterloo, ON, Canada
Katrina Fleming
Affiliation:
Department of Radiation Therapy, Grand River Regional Cancer Centre, Kitchener, ON, Canada
Ronald Snelgrove
Affiliation:
Department of Medical Physics, Grand River Regional Cancer Centre, Kitchener, ON, Canada
Anmol Bhangu
Affiliation:
Department of Physics and Astronomy, University of Waterloo, Waterloo, ON, Canada
Darin Gopaul
Affiliation:
Department of Radiation Oncology, Grand River Regional Cancer Centre, Kitchener, ON, Canada
*
Author for correspondence: Ernest Osei, Department of Medical Physics, Grand River Regional Cancer Centre, Kitchener, ON, Canada. E-mail: ernest.osei@grhosp.on.ca

Abstract

Objectives:

Lung cancer is the most commonly diagnosed cancer in Canada and the leading cause of cancer-related mortality in both men and women in North America. Surgery is usually the primary treatment option for early-stage non-small cell lung cancer (NSCLC). However, for patients who may not be suitable candidates for surgery, stereotactic body radiation therapy (SBRT) is an alternative method of treatment. SBRT has proven to be an effective technique for treating NSCLC patients by focally administering high radiation dose to the tumour with acceptable risk of toxicity to surrounding healthy tissues. The goal of this comprehensive retrospective dosimetric study is to compare the dosimetric parameters between three-dimensional conformal radiation therapy (3DCRT) and volumetric-modulated arc therapy (VMAT) lung SBRT treatment plans for two prescription doses.

Methods:

We retrospectively analysed and compared lung SBRT treatment plans of 263 patients treated with either a 3DCRT non-coplanar or with 2–3 VMAT arcs technique at 48 Gy in 4 fractions (48 Gy/4) or 50 Gy in 5 fractions (50 Gy/5) prescribed to the planning target volume (PTV), typically encompassing the 80% isodose volume. All patients were treated on either a Varian 21EX or TrueBeam linear accelerator using 6-MV or 10-MV photon beams.

Results:

The mean PTV V95% and V100% for treatment plans at 48 Gy/4 are 99·4 ± 0·6% and 96·0 ± 1·0%, respectively, for 3DCRT and 99·7 ± 0·4% and 96·4 ± 3·4%, respectively, for VMAT. The corresponding mean PTV V95% and V100% at 50 Gy/5 are 99·0 ± 1·4% and 95·5 ± 2·5% for 3DCRT and 99·5 ± 0·8% and 96·1 ± 1·6% for VMAT. The CIRI and HI5/95 for the PTV at 48 Gy/4 are 1·1 ± 0·1 and 1·2 ± 0·0 for 3DCRT and 1·0 ± 0·1 and 1·2 ± 0·0 for VMAT. The corresponding CIRI and HI5/95 at 50 Gy/5 are 1·1 ± 0·1 and 1·3 ± 0·1 for 3DCRT and 1·0 ± 0·1 and 1·2 ± 0·0 for VMAT. The mean R50% and D2cm at 48 Gy/4 are 5·0 ± 0·8 and 61·2 ± 7·0% for 3DCRT and 4·9 ± 0·8 and 57·8 ± 7·9% for VMAT. The corresponding R50% and D2cm at 50 Gy/5 are 4·7 ± 0·5 and 65·5 ± 9·4% for 3DCRT and 4·7 ± 0·7 and 60·0 ± 7·2% for VMAT.

Conclusion:

The use of 3DCRT or VMAT technique for lung SBRT is an efficient and reliable method for achieving dose conformity, rapid dose fall-off and minimising doses to the organs at risk. The VMAT technique resulted in improved dose conformity, rapid dose fall-off from the PTV compared to 3DCRT, although the magnitude may not be clinically significant.

Type
Original Article
Copyright
© The Author(s), 2020. Published by Cambridge University Press

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References

Canadian Cancer Society. Lung Cancer Statistics. 2020. https://www.cancer.ca/en/cancer-information/cancer-type/lung/statistics/?region=on. Accessed on 19th April 2020.Google Scholar
Brenner, DR, Weir, HK, Demers, AA et al. Projected estimates of cancer in Canada in 2020. Can Med Assoc J 2020; 192 (9): E199E205.CrossRefGoogle ScholarPubMed
Polański, J, Chabowski, M, Jankowska-Polańska, B, Janczak, D, Rosinczuk, J. Histological subtype of lung cancer affects acceptance of illness, severity of pain, and quality of life. J Pain Res 2018; 11: 727733.CrossRefGoogle Scholar
Zheng, X, Schipper, M, Kidwell, K et al. Survival outcome after stereotactic body radiation therapy and surgery for stage I non-small cell lung cancer: a meta-analysis. Int J Radiat Oncol Biolo Phys 2014; 90 (3): 603611.CrossRefGoogle Scholar
Infante, M, Berghmans, T, Heuvelmans, MA, Hillerdal, G, Oudkerk, M. Slow-growing lung cancer as an emerging entity: from screening to clinical management. Eur Respir J 2013 Dec; 42 (6): 17061722.CrossRefGoogle ScholarPubMed
Mouillet, G, Monnet, E, Milleron, B et al. Pathologic complete response to preoperative chemotherapy predicts cure in early-stage non–small-cell lung cancer: combined analysis of two IFCT randomized trials. J Thorac Oncol 2012 May 1; 7 (5): 841849.CrossRefGoogle ScholarPubMed
Yu, X, Dai, W, Xu, Y. Survival outcome after stereotactic body radiation therapy and surgery for early stage non-small cell lung cancer: a meta-analysis. J Invest Surg 2018 Sep 3; 31 (5): 440447.CrossRefGoogle Scholar
Eriguchi, T, Takeda, A, Sanuki, N et al. Stereotactic body radiotherapy for operable early-stage non-small cell lung cancer. Lung Cancer 2017; 109: 6267.CrossRefGoogle ScholarPubMed
Wang, X, Zamdborg, L, Ye, H, Grills, IS, Yan, D. A matched-pair analysis of stereotactic body radiotherapy (SBRT) for oligometastatic lung tumors from colorectal cancer versus early stage non-small cell lung cancer. BMC Cancer 2018; 18 (1): 962.CrossRefGoogle ScholarPubMed
Goldsmith, C, Gaya, A. Stereotactic ablative body radiotherapy (SABR) for primary and secondary lung tumours. Cancer Imaging 2012 Sep 28; 12 (2): 351360.CrossRefGoogle ScholarPubMed
Strand, T, Rostad, H, Møller, B, Norstein, J. Survival after resection for primary lung cancer: a population based study of 3211 resected patients. Thorax 2006 Aug; 61 (8): 710715.CrossRefGoogle ScholarPubMed
Xiao, Y, Papiez, L, Paulus, R et al. Dosimetric evaluation of heterogeneity corrections for RTOG 0236: stereotactic body radiotherapy of inoperable stage I-II non–small-cell lung cancer. Int J Radiat Oncol Biolo Phys 2009; 73 (4): 12351242.CrossRefGoogle ScholarPubMed
Senan, S, Palma, DA, Lagerwaard, FJ. Stereotactic ablative radiotherapy for stage I NSCLC: Recent advances and controversies. J Thorac Dis 2011; 3 (3): 189196.Google Scholar
Sun, X, Deng, L, Lu, Y. Challenges and opportunities of using stereotactic body radiotherapy with anti-angiogenesis agents in tumor therapy. Chinese J Cancer Res 2018 Feb; 30 (1): 147156.CrossRefGoogle ScholarPubMed
Vlachaki, M, Castellon, I, Leite, C, Perkins, T, Ahmad, S. Impact of respiratory gating using 4-dimensional computed tomography on the dosimetry of tumor and normal tissues in patients with thoracic malignancies. Am J Clin Oncol 2009 Jun; 32 (3): 262268.CrossRefGoogle ScholarPubMed
Toesca, DAS, Koong, AJ, von Eyben, R, Koong, AC, Chang, DT. Stereotactic body radiation therapy for adrenal gland metastases: outcomes and toxicity. Adv Radiat Oncol 2018; 3 (4): 621629.CrossRefGoogle ScholarPubMed
Baumann, P, Nyman, J, Hoyer, M et al. Outcome in a prospective phase II trial of medically inoperable stage I non–small-cell lung cancer patients treated with stereotactic body radiotherapy. J Clin Oncol 2009; 27 (20): 32903296.CrossRefGoogle Scholar
Baumann, P, Nyman, J, Lax, I et al. Factors important for efficacy of stereotactic body radiotherapy of medically inoperable stage I lung cancer. A retrospective analysis of patients treated in the Nordic countries. Acta Oncol 2006; 45 (7): 787.CrossRefGoogle Scholar
Ball, D, Mai, GT, Vinod, S et al. Stereotactic ablative radiotherapy versus standard radiotherapy in stage 1 non-small-cell lung cancer (TROG 09.02 CHISEL): a phase 3, open-label, randomised controlled trial. Lancet Oncol 2019; 20 (4): 494503.CrossRefGoogle ScholarPubMed
Prezzano, KM, Ma, SJ, Hermann, GM, Rivers, CI, Gomez-Suescun, JA, Singh, AK. Stereotactic body radiation therapy for non-small cell lung cancer: a review. World J Clin Oncol 2019 Jan 10; 10 (1): 1427.CrossRefGoogle ScholarPubMed
Timmerman, R, McGarry, R, Yiannoutsos, C et al. Excessive toxicity when treating central tumors in a phase II study of stereotactic body radiation therapy for medically inoperable early-stage lung cancer. J Clin Oncol 2006; 24 (30): 48334839.CrossRefGoogle Scholar
Senthi, S, Lagerwaard, FJ, Haasbeek, CJ, Slotman, BJ, Senan, S. Patterns of disease recurrence after stereotactic ablative radiotherapy for early stage non-small-cell lung cancer: a retrospective analysis. Lancet Oncol 2012; 13 (8): 802809.CrossRefGoogle ScholarPubMed
Zhao, Y, Khawandanh, E, Thomas, S et al. Outcomes of stereotactic body radiotherapy 60 Gy in 8 fractions when prioritizing organs at risk for central and ultracentral lung tumors. Radiat Oncol (London, England) 2020; 15 (1): 61.CrossRefGoogle ScholarPubMed
Herbert, C, Kwa, W, Nakano, S et al. Stereotactic body radiotherapy: volumetric modulated arc therapy versus 3D non-coplanar conformal radiotherapy for the treatment of early stage lung cancer. Technol Cancer Res Treat 2013 Dec; 12 (6): 511516.CrossRefGoogle ScholarPubMed
Huang, B, Lu, J, Lin, P, Chen, J, Li, D, Chen, C. Radiobiological modeling analysis of the optimal fraction scheme in patients with peripheral non-small cell lung cancer undergoing stereotactic body radiotherapy. Sci Rep 2015 Dec 11; 5 (1): 18010.CrossRefGoogle ScholarPubMed
Kim, Y, Chung, J, Kim, J et al. Dosimetric comparison of a 6-MV flattening-filter and a flattening-filter-free beam for lung stereotactic ablative radiotherapy treatment. J Korean Phys Soc 2015 Nov; 67 (9): 16721678.CrossRefGoogle Scholar
Weyh, A, Konski, A, Nalichowski, A, Maier, J, Lack, D. Lung SBRT: dosimetric and delivery comparison of RapidArc, TomoTherapy, and IMRT. J Appl Clin Med Phys 2013; 14 (4): 313.CrossRefGoogle Scholar
van Baardwijk, A, Tomé, WA, van Elmpt, W et al. Is high-dose stereotactic body radiotherapy (SBRT) for stage I non-small cell lung cancer (NSCLC) overkill? A systematic review. Radiother Oncol 2012; 105 (2): 145149.CrossRefGoogle Scholar
Ricco, A, Davis, J, Rate, W et al. Lung metastases treated with stereotactic body radiotherapy: the RSSearch® patient Registry’s experience. Radiat Oncol (London, England) 2017; 12 (1): 35.CrossRefGoogle ScholarPubMed
Uematsu, M, Shioda, A, Suda, A et al. Computed tomography-guided frameless stereotactic radiotherapy for stage I non-small cell lung cancer: a 5-year experience. Int J Radiat Oncol Biolo Phys 2001; 51 (3): 666670.CrossRefGoogle Scholar
Korzets Ceder, Y, Fenig, E, Popvtzer, A et al. Stereotactic body radiotherapy for central lung tumors, yes we can. Radiat Oncol (London, England) 2018 Apr 25; 13 (1): 77.CrossRefGoogle ScholarPubMed
Heinzerling, JH, Anderson, JF, Papiez, L et al. Four-dimensional computed tomography scan analysis of tumor and organ motion at varying levels of abdominal compression during stereotactic treatment of lung and liver. Int J Radiat Oncol Biolo Phys 2008; 70 (5): 15711578.CrossRefGoogle ScholarPubMed
Rana, S, Rogers, K, Pokharel, S, Cheng, C. Evaluation of acuros XB algorithm based on RTOG 0813 dosimetric criteria for SBRT lung treatment with RapidArc. J Appl Clin Med Phys 2014 Jan; 15 (1): 118129.CrossRefGoogle ScholarPubMed
Nagata, Y, Kimura, T. Stereotactic body radiotherapy (SBRT) for Stage I lung cancer. Jpn J Clin Oncol 2018 May 1; 48 (5): 405409.CrossRefGoogle ScholarPubMed
Mampuya, WA, Matsuo, Y, Ueki, N et al. The impact of abdominal compression on outcome in patients treated with stereotactic body radiotherapy for primary lung cancer. J Radiat Res 2014 Sep; 55 (5): 934939.CrossRefGoogle ScholarPubMed
McNair, HA, Brock, J, Symonds-Tayler, JRN et al. Feasibility of the use of the Active Breathing Coordinator™ (ABC) in patients receiving radical radiotherapy for non-small cell lung cancer (NSCLC). Radiother Oncol 2009; 93 (3): 424429.CrossRefGoogle Scholar
Panakis, N, McNair, HA, Christian, JA, Mendes, R, Symonds-Tayler, JRN, Knowles, C, et al. Defining the margins in the radical radiotherapy of non-small cell lung cancer (NSCLC) with active breathing control (ABC) and the effect on physical lung parameters. Radiother Oncol 2007; 87 (1): 6573.CrossRefGoogle Scholar
Shen, Y, Zhang, H, Wang, J et al. Hypofractionated radiotherapy for lung tumors with online cone beam CT guidance and active breathing control. Radiat Oncol (London, England) 2010 Feb 27; 5 (1): 19.CrossRefGoogle ScholarPubMed
Videtic, GMM, Singh, AK, Chang, JY et al. NRG Oncology.A randomized phase II study comparing 2 stereotactic body radiation therapy (SBRT) schedules for medically inoperable patients with stage I peripheral non-small cell lung cancer. RTOG 0915. Philadelphia, PA: RTOG; 2014. http://www.remotecmd.com/uploads/3/1/0/6/31069079/0915_sbrtlung.pdf. Accessed on 1st September 2020.CrossRefGoogle Scholar
Bezjak, A, Bradley, J, Gaspar, L et al. NRG Oncology. Seamless phase I/II study of stereotactic lung radiotherapy (SBRT) for early stage, centrally located, non-small cell lung cancer (NSCLC) in medically inoperable patients. RTOG 0813. Philadelphia, PA: RTOG; 2014. http://www.remotecmd.com/uploads/3/1/0/6/31069079/0813_sbrtlung.pdf. Accessed 1st September 2020.Google Scholar
ICRU-62. International Commission on Radiation Units and Measurements (ICRU). Prescribing, recording, and reporting photon beam therapy. Bethesda, MD; 1999.Google Scholar
Ong, CL, Verbakel, WFAR, Cuijpers, JP, Slotman, BJ, Lagerwaard, FJ, Senan, S. Stereotactic radiotherapy for peripheral lung tumors: a comparison of volumetric modulated arc therapy with 3 other delivery techniques. Radiother Oncol 2010; 97 (3): 437442.CrossRefGoogle ScholarPubMed
Hrbacek, J, Lang, S, Graydon, SN, Klöck, S, Riesterer, O. Dosimetric comparison of flattened and unflattened beams for stereotactic ablative radiotherapy of stage I non-small cell lung cancer. Med Phys 2014 Mar; 41 (3): 031709-1–031709-7CrossRefGoogle ScholarPubMed
Shen, L, Liu, C, Jin, J et al. Association of lung and heart dose with survival in patients with non-small cell lung cancer underwent volumetric modulated arc therapy. Cancer Manag Res 2019; 11: 60916098.CrossRefGoogle ScholarPubMed
Cong, Y, Sun, B, Wang, J et al. Outcomes and toxicity of stereotactic body radiation therapy for advanced stage ultra-central non-small cell lung cancer. Thorac Cancer 2019; 10 (7): 15671575.CrossRefGoogle ScholarPubMed
Reyngold, M, Wu, AJ, McLane, A et al. Toxicity and outcomes of thoracic re-irradiation using stereotactic body radiation therapy (SBRT). Radiat Oncol (London, England) 2013 Apr 25; 8 (1): 99.CrossRefGoogle Scholar
Nagata, Y, Takayama, K, Matsuo, Y et al. Clinical outcomes of a phase I/II study of 48 Gy of stereotactic body radiotherapy in 4 fractions for primary lung cancer using a stereotactic body frame. Int J Radiat Oncol Biolo Phys 2005; 63 (5): 14271431.CrossRefGoogle ScholarPubMed
Singh, D, Chen, Y, Hare, MZ et al. Local control rates with five-fraction stereotactic body radiotherapy for oligometastatic cancer to the lung. J Thorac Dis 2014 Apr; 6 (4): 369374.Google ScholarPubMed
Qiao, X, Tullgren, O, Lax, I, Sirzén, F, Lewensohn, R. The role of radiotherapy in treatment of stage I non-small cell lung cancer. Lung Cancer 2003; 41 (1): 111.CrossRefGoogle ScholarPubMed
Onishi, H, Araki, T, Shirato, H et al. Stereotactic hypofractionated high-dose irradiation for stage I nonsmall cell lung carcinoma. Cancer 2004; 101 (7): 16231631.CrossRefGoogle ScholarPubMed
Park, S, Urm, S, Cho, H. Analysis of biologically equivalent dose of stereotactic body radiotherapy for primary and metastatic lung tumors. Cancer Res Treat 2014 Oct; 46 (4): 403410.CrossRefGoogle ScholarPubMed
Senthi, S, Haasbeek, CJA, Slotman, BJ, Senan, S. Outcomes of stereotactic ablative radiotherapy for central lung tumours: a systematic review. Radiother Oncol 2013; 106 (3): 276282.CrossRefGoogle ScholarPubMed
Chaudhuri, AA, Tang, C, Binkley, MS et al. Stereotactic ablative radiotherapy (SABR) for treatment of central and ultra-central lung tumors. Lung Cancer 2015; 89 (1): 5056.CrossRefGoogle ScholarPubMed
Machtay, M, Bae, K, Movsas, B et al. Higher biologically effective dose of radiotherapy is associated with improved outcomes for locally advanced non–small cell lung carcinoma treated with chemoradiation: an analysis of the radiation therapy oncology group. Int J Radiat Oncol Biolo Phys 2012; 82 (1): 425434.CrossRefGoogle ScholarPubMed
Inoue, A, Kunitoh, H, Sekine, I, Sumi, M, Tokuuye, K, Saijo, N. Radiation pneumonitis in lung cancer patients: a retrospective study of risk factors and the long-term prognosis. Int J Radiat Oncol Biolo Phys 2001; 49 (3): 649655.CrossRefGoogle ScholarPubMed
Kang, KH, Okoye, CC, Patel, RB et al. Complications from stereotactic body radiotherapy for lung cancer. Cancers 2015 Jun 15; 7 (2): 9811004.CrossRefGoogle ScholarPubMed
Chen, Z, Wu, Z, Ning, W. Advances in molecular mechanisms and treatment of radiation-induced pulmonary fibrosis. Transl Oncol 2019 Jan; 12 (1): 162169.CrossRefGoogle ScholarPubMed
Chia, BSH, Master, Z. Pitfalls in lung stereotactic body radiotherapy—a review of organ toxicities and dose constraints. J Xiangya Med 2018 Oct; 3: 36.CrossRefGoogle Scholar
Sahgal, A, Chang, JH, Ma, L et al. Spinal cord dose tolerance to stereotactic body radiation therapy. Int J Radiat Oncol Biolo Phys 2019 Oct: 113.Google ScholarPubMed
Ming, X, Feng, Y, Liu, H, Zhang, Y, Zhou, L, Deng, J. Cardiac exposure in the dynamic conformal arc therapy, intensity-modulated radiotherapy and volumetric modulated arc therapy of lung cancer. PLoS One 2015; 10 (12): e0144211.CrossRefGoogle ScholarPubMed
Bradley, JD, Hu, C, Komaki, RR et al. Long-term results of NRG oncology RTOG 0617: standard- versus high-dose chemoradiotherapy with or without cetuximab for unresectable stage III non–small-cell lung cancer. J Clin Oncol 2020; 38 (7): 706714.CrossRefGoogle ScholarPubMed
Pokhrel, D, Sood, S, Badkul, R et al. Assessment of Monte Carlo algorithm for compliance with RTOG 0915 dosimetric criteria in peripheral lung cancer patients treated with stereotactic body radiotherapy. J Appl Clin Med Phys 2016 May; 17 (3): 277293.CrossRefGoogle ScholarPubMed
Taremi, M, Hope, A, Lindsay, P et al. Predictors of Radiotherapy Induced Bone Injury (RIBI) after stereotactic lung radiotherapy. Radiat Oncol (London, England) 2012; 7 (1): 159.CrossRefGoogle ScholarPubMed
Pettersson, N, Nyman, J, Johansson, K. Radiation-induced rib fractures after hypofractionated stereotactic body radiation therapy of non-small cell lung cancer: a dose– and volume–response analysis. Radiother Oncol 2009; 91 (3): 360368.CrossRefGoogle ScholarPubMed
Asai, K, Shioyama, Y, Nakamura, K et al. Radiation-induced rib fractures after hypofractionated stereotactic body radiation therapy: risk factors and dose–volume relationship. Int J Radiat Oncol Biolo Phys 2012; 84 (3): 768773.CrossRefGoogle ScholarPubMed
Tomé, WA, Hodge, CW, Mehta, MP, Bentzen, SM. Incidence of rib fractures after stereotactic body radiotherapy for peripheral lung lesions: clinical experience and dose response estimation. J Radiosurg SBRT 2011; 1 (2): 155161.Google ScholarPubMed
Aoki, M, Sato, M, Hirose, K et al. Radiation-induced rib fracture after stereotactic body radiotherapy with a total dose of 54–56 Gy given in 9–7 fractions for patients with peripheral lung tumor: impact of maximum dose and fraction size. Radiat Oncol (London, England) 2015 Apr 22; 10 (1): 99.CrossRefGoogle ScholarPubMed
Baker, S, Fairchild, A. Radiation-induced esophagitis in lung cancer. Lung Cancer (Auckland) 2016; 7: 119127.Google ScholarPubMed
Murrell, DH, Laba, JM, Erickson, A, Millman, B, Palma, DA, Louie, AV. Stereotactic ablative radiotherapy for ultra-central lung tumors: prioritize target coverage or organs at risk? Radiat Oncol (London, England) 2018; 13 (1): 57, pg 1–8.CrossRefGoogle ScholarPubMed
Lischalk, JW, Malik, RM, Collins, SP, Collins, BT, Matus, IA, Anderson, ED. Stereotactic body radiotherapy (SBRT) for high-risk central pulmonary metastases. Radiat Oncol (London, England) 2016; 11 (1): 28.CrossRefGoogle ScholarPubMed
Hoppe, BS, Laser, B, Kowalski, AV et al. Acute skin toxicity following stereotactic body radiation therapy for stage I non–small-cell lung cancer: who’s at risk? Int J Radiat Oncol Biolo Phys 2008; 72 (5): 12831286.CrossRefGoogle Scholar