ABSTRACT
Radiotherapy (RT) is used alone or in combination with chemotherapy in the treatment of many cancers in oncology. Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT), which is widely used in evaluating the response to RT, is a guide in the treatment process and course of the patient and has an important role in determining survival and prognosis. In case of response to treatment, the planned target volume and RT dose can be reduced, and treatment intensity can be increased in resistant tumors. The most important problem in evaluating the response to RT with PET/CT is to distinguish between residual tumor and radiation-induced inflammation and changes. In evaluating response to treatment, the metabolic and anatomical response can be evaluated together or a metabolic evaluation can be performed. Although visual and/or quantitative criteria and PET parameters are used in the metabolic evaluation, there are not standard quantitative criteria for evaluating response to RT. In this review, the place and importance of PET/CT, which has an important role in radiation oncology practice, in evaluating the response to RT will be discussed.
References
1Eisenhauer EA, Therasse P, Bogaerts J, et al. New response evaluation criteria in solid tumours: revised RECIST guideline (version 1.1). Eur J Cancer 2009;45:228-247.
2Wahl RL, Jacene H, Kasamon Y, Lodge MA. From RECIST to PERCIST: Evolving Considerations for PET response criteria in solid tumors. J Nucl Med 2009;50 Supp 1:122-150.
3Decazes P, Thureau S, Modzelewski R, Damilleville-Martin M, Bohn P, Vera P. Benefits of positron emission tomography scans for the evaluation of radiotherapy. Cancer Radiother 2020;24:388-397.
4Vera P, Mezzani-Saillard S, Edet-Sanson A, et al. FDG PET during radiochemotherapy is predictive of outcome at 1 year in non-small-cell lung cancer patients: a prospective multicentre study (RTEP2). Eur J Nucl Med Mol Imaging 2014;41:1057-1065.
5Cliffe H, Patel C, Prestwich R, Scarsbrook A. Radiotherapy response evaluation using FDG PET-CT-established and emerging applications. Br J Radiol 2017;90:20160764.
6Huang SH, O’Sullivan B, Xu W, et al. Temporal nodal regression and regional control after primary radiation therapy for N2-N3 head-and-neck cancer stratified by HPV status. Int J Radiat Oncol Biol Phys 2013;87:1078-1085.
7Castadot P, Geets X, Lee JA, Grégoire V. Adaptive functional image-guided IMRT in pharyngo-laryngeal squamous cell carcinoma: is the gain in dose distribution worth the effort? Radiother Oncol 2011;101:343-350.
8Decazes P, Thureau S, Dubray B, Vera P. How to use PET/CT in the evaluation of response to radiotherapy. Q J Nucl Med Mol Imaging 2018;62:152-164.
9Khan R, Seltzer M. PET Imaging of Tumor Hypoxia in Head and Neck Cancer: A Primer for Neuroradiologists. Neuroimaging Clin N Am 2020;30:325-339.
10Marcu LG. Imaging Biomarkers of Tumour Proliferation and Invasion for Personalised Lung Cancer Therapy. J Pers Med 2020;10:222.
11Helsen N, Van den Wyngaert T, Carp L, Stroobants S. FDG-PET/CT for treatment response assessment in head and neck squamous cell carcinoma: a systematic review and meta-analysis of diagnostic performance. Eur J Nucl Med Mol Imaging 2018;45:1063-1071.
12Helsen N, Roothans D, Van Den Heuvel B, et al. 18F-FDG-PET/CT for the detection of disease in patients with head and neck cancer treated with radiotherapy. PLoS One 2017;12:e0182350.
13Liu HY, Milne R, Lock G, et al. Utility of a repeat PET/CT scan in HPV-associated Oropharyngeal Cancer following incomplete nodal response from (chemo)radiotherapy. Oral Oncol 2019;88:153-159.
14Van den Wyngaert T, Helsen N, Carp L, et al. Fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography After Concurrent Chemoradiotherapy in Locally Advanced Head-and-Neck Squamous Cell Cancer: The ECLYPS Study. J Clin Oncol 2017;35:3458-3464.
15van Elmpt W, Ollers M, Dingemans AM, Lambin P, De Ruysscher D. Response assessment using 18F-FDG PET early in the course of radiotherapy correlates with survival in advanced-stage non-small cell lung cancer. J Nucl Med 2012;53:1514-1520.
16Atasever T, Demirci E, Soydal Ç, Burak Z, Ucmak G, Bozkurt MF. F-18 FDG PET/BT Onkolojik Uygulama Kılavuzu: Tedavi Yanıtının Belirlenmesi. Nucl Med Semin 2020;4:358-369.
17Prestwich RJ, Subesinghe M, Gilbert A, Chowdhury FU, Sen M, Scarsbrook AF. Delayed response assessment with FDG-PET-CT following (chemo) radiotherapy for locally advanced head and neck squamous cell carcinoma. Clin Radiol 2012;67:966-975.
18Shankar LK, Hoffman JM, Bacharach S, et al. Consensus recommendations for the use of 18F-FDG PET as an indicator of therapeutic response in patients in National Cancer Institute Trials. J Nucl Med 2006;47:1059-1066.
19Sugawara Y, Zasadny KR, Neuhoff AW, Wahl RL. Reevaluation of the standardized uptake value for FDG: variations with body weight and methods for correction. Radiology 1999;213:521-525.
20Karapolat İ. Akciğer Kanserinde Tedavi Yanıtını Değerlendirmede FDG PET/BT Görüntüleme. Nucl Med Semin 2018;4:43-51.
21Yildirim BA, Torun N, Guler OC, Onal C. Prognostic value of metabolic tumor volume and total lesion glycolysis in esophageal carcinoma patients treated with definitive chemoradiotherapy. Nucl Med Commun 2018;39:553-563.
22Im HJ, Bradshaw T, Solaiyappan M, Cho SY. Current Methods to Define Metabolic Tumor Volume in Positron Emission Tomography: Which One is Better? Nucl Med Mol Imaging 2018;52:5-15.
23 Bibault JE, Xing L, Giraud P, et al. Radiomics: A primer for the radiation oncologist. Cancer Radiother 2020;24:403-410.
24Mac Manus MP, Hicks RJ, Matthews JP, et al. Positron emission tomography is superior to computed tomography scanning for response-assessment after radical radiotherapy or chemoradiotherapy in patients with non-small-cell lung cancer. J Clin Oncol 2003;21:1285-1292.
25Goel R, Moore W, Sumer B, Khan S, Sher D, Subramaniam RM. Clinical Practice in PET/CT for the Management of Head and Neck Squamous Cell Cancer. AJR Am J Roentgenol 2017;209:289-303.
26Mac Manus MP, Hicks RJ, Matthews JP, et al. Positron emission tomography is superior to computed tomography scanning for response-assessment after radical radiotherapy or chemoradiotherapy in patients with non-small-cell lung cancer. J Clin Oncol 2003;21:1285-1292.
27Sheikhbahaei S, Mena E, Marcus C, Wray R, Taghipour M, Subramaniam RM. 18F-FDG PET/CT: Therapy Response Assessment Interpretation (Hopkins Criteria) and Survival Outcomes in Lung Cancer Patients. J Nucl Med 2016;57:855-860.
28Werner JM, Lohmann P, Fink GR, Langen KJ, Galldiks N. Current Landscape and Emerging Fields of PET Imaging in Patients with Brain Tumors. Molecules 2020;25:1471.
29Wen PY, Macdonald DR, Reardon DA, et al. Updated response assessment criteria for high-grade gliomas: response assessment in neuro-oncology working group. J Clin Oncol 2010;28:1963-1972.
30Law I, Albert NL, Arbizu J, et al. Joint EANM/EANO/RANO practice guidelines/SNMMI procedure standards for imaging of gliomas using PET with radiolabelled amino acids and [18F]FDG: version 1.0. Eur J Nucl Med Mol Imaging 2019;46:540-557.
31Chao ST, Suh JH, Raja S, Lee SY, Barnett G. The sensitivity and specificity of FDG PET in distinguishing recurrent brain tumor from radionecrosis in patients treated with stereotactic radiosurgery. Int J Cancer 2001;96:191-197.
32Albert NL, Weller M, Suchorska B, et al. Response Assessment in Neuro-Oncology working group and European Association for Neuro-Oncology recommendations for the clinical use of PET imaging in gliomas. Neuro Oncol 2016;18:1199-1208.
33Gupta M, Gupta T, Purandare N, et al. Utility of flouro-deoxy-glucose positron emission tomography/computed tomography in the diagnostic and staging evaluation of patients with primary CNS lymphoma. CNS Oncol 2019;8:CNS46.
34Dunet V, Pomoni A, Hottinger A, Nicod-Lalonde M, Prior JO. Performance of 18F-FET versus 18F-FDG-PET for the diagnosis and grading of brain tumors: systematic review and meta-analysis. Neuro Oncol 2016;18:426-434.
35Machtay M, Duan F, Siegel BA, et al. Prediction of survival by [18F]fluorodeoxyglucose positron emission tomography in patients with locally advanced non-small-cell lung cancer undergoing definitive chemoradiation therapy: results of the ACRIN 6668/RTOG 0235 trial. J Clin Oncol 2013;31:3823-3830.
36Markovina S, Duan F, Snyder BS, Siegel BA, Machtay M, Bradley JD. Regional Lymph Node Uptake of [(18)F]Fluorodeoxyglucose After Definitive Chemoradiation Therapy Predicts Local-Regional Failure of Locally Advanced Non-Small Cell Lung Cancer: Results of ACRIN 6668/RTOG 0235. Int J Radiat Oncol Biol Phys 2015;93:597-605.
37Na F, Wang J, Li C, Deng L, Xue J, Lu Y. Primary tumor standardized uptake value measured on F18-Fluorodeoxyglucose positron emission tomography is of prediction value for survival and local control in non-small-cell lung cancer receiving radiotherapy: meta-analysis. J Thorac Oncol 2014;9:834-842.
38Turgeon GA, Iravani A, Akhurst T, et al. What (18)F-FDG PET Response-Assessment Method Best Predicts Survival After Curative-Intent Chemoradiation in Non-Small Cell Lung Cancer: EORTC, PERCIST, Peter Mac Criteria, or Deauville Criteria? J Nucl Med 2019;60:328-334.
39Schollaert P, Crott R, Bertrand C, D’Hondt L, Borght TV, Krug B. A systematic review of the predictive value of (18)FDG-PET in esophageal and esophagogastric junction cancer after neoadjuvant chemoradiation on the survival outcome stratification. J Gastrointest Surg 2014;18:894-905.
40Elliott JA, O’Farrell NJ, King S, et al. Value of CT-PET after neoadjuvant chemoradiation in the prediction of histological tumour regression, nodal status and survival in oesophageal adenocarcinoma. Br J Surg 2014;101:1702-1711.
41Flamen P, Van Cutsem E, Lerut A, et al. Positron emission tomography for assessment of the response to induction radiochemotherapy in locally advanced oesophageal cancer. Ann Oncol 2002;13:361-368.
42Kukar M, Alnaji RM, Jabi F, et al. Role of Repeat 18F-Fluorodeoxyglucose Positron Emission Tomography Examination in Predicting Pathologic Response Following Neoadjuvant Chemoradiotherapy for Esophageal Adenocarcinoma. JAMA Surg 2015;150:555-562.
43Monjazeb AM, Riedlinger G, Aklilu M, et al. Outcomes of patients with esophageal cancer staged with [¹⁸F]fluorodeoxyglucose positron emission tomography (FDG-PET): can postchemoradiotherapy FDG-PET predict the utility of resection? J Clin Oncol 2010;28:4714-4721.
44Wu AJ, Goodman KA. Clinical tools to predict outcomes in patients with esophageal cancer treated with definitive chemoradiation: are we there yet? J Gastrointest Oncol 2015;6:53-59.
