TY - JOUR
T1 - Predicted secondary malignancies following proton versus photon radiation for oropharyngeal cancers
AU - Jain, Varsha
AU - Irmen, Peyton
AU - O’Reilly, Shannon
AU - Vogel, Jennifer H.
AU - Lin, Liyong
AU - Lin, Alexander
N1 - Publisher Copyright:
Copyright 2020 The Author(s)
PY - 2021/3/1
Y1 - 2021/3/1
N2 - Purpose: There has been a recent epidemic of human papillomavirus (HPV)–positive oropharyngeal cancer, accounting for 70% to 80% of diagnosed cases. These patients have an overall favorable prognosis and are typically treated with a combination of surgery, chemotherapy, and radiation. Because these patients live longer, they are at risk of secondary malignant neoplasms (SMNs) associated with radiation therapy. Therefore, we assessed the predicted risk of SMNs after adjuvant radiation therapy with intensity-modulated proton therapy (IMPT) compared with intensity modulated photon radiation therapy (IMRT) in patients with HPV- positive oropharyngeal cancers after complete resection. Materials and Methods: Thirteen consecutive patients with HPV-positive oropharyngeal cancers treated with postoperative radiation alone were selected. All patients were treated with pencil beam scanning IMPT to a total dose of 60 Gy in 2 Gy fractions. The IMRT plans were generated for clinical backup and were used for comparative purposes. The SMN risk was calculated based on an organ equivalent dose model for the linear-exponential dose-response curve. Results: Median age of the patient cohort was 63 years (range, 47-73 years). There was no difference in target coverage between IMPT and IMRT plans. We noted significant reductions in mean mandible, contralateral parotid, lung and skin organ equivalent doses with IMPT compared with IMRT plans (P< .001). Additionally, a significant decrease in the risk of SMNs with IMPT was observed for all the evaluated organs. Per our analysis, for patients with oropharyngeal cancers diagnosed at a national median age of 54 years with an average life expectancy of 27 years (per national Social Security data), 4 excess SMNs per 100 patients could be avoided by treating them with IMPT versus IMRT. Conclusions: Treatment with IMPT can achieve comparable target dose coverage while significantly reducing the dose to healthy organs, which can lead to fewer predicted SMNs compared with IMRT.
AB - Purpose: There has been a recent epidemic of human papillomavirus (HPV)–positive oropharyngeal cancer, accounting for 70% to 80% of diagnosed cases. These patients have an overall favorable prognosis and are typically treated with a combination of surgery, chemotherapy, and radiation. Because these patients live longer, they are at risk of secondary malignant neoplasms (SMNs) associated with radiation therapy. Therefore, we assessed the predicted risk of SMNs after adjuvant radiation therapy with intensity-modulated proton therapy (IMPT) compared with intensity modulated photon radiation therapy (IMRT) in patients with HPV- positive oropharyngeal cancers after complete resection. Materials and Methods: Thirteen consecutive patients with HPV-positive oropharyngeal cancers treated with postoperative radiation alone were selected. All patients were treated with pencil beam scanning IMPT to a total dose of 60 Gy in 2 Gy fractions. The IMRT plans were generated for clinical backup and were used for comparative purposes. The SMN risk was calculated based on an organ equivalent dose model for the linear-exponential dose-response curve. Results: Median age of the patient cohort was 63 years (range, 47-73 years). There was no difference in target coverage between IMPT and IMRT plans. We noted significant reductions in mean mandible, contralateral parotid, lung and skin organ equivalent doses with IMPT compared with IMRT plans (P< .001). Additionally, a significant decrease in the risk of SMNs with IMPT was observed for all the evaluated organs. Per our analysis, for patients with oropharyngeal cancers diagnosed at a national median age of 54 years with an average life expectancy of 27 years (per national Social Security data), 4 excess SMNs per 100 patients could be avoided by treating them with IMPT versus IMRT. Conclusions: Treatment with IMPT can achieve comparable target dose coverage while significantly reducing the dose to healthy organs, which can lead to fewer predicted SMNs compared with IMRT.
KW - HPV-positive
KW - Oropharyngeal cancer
KW - Protons
KW - Radiation therapy
KW - Secondary malignancies
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U2 - 10.14338/IJPT-19-00076.1
DO - 10.14338/IJPT-19-00076.1
M3 - Article
C2 - 32582814
AN - SCOPUS:85118231563
SN - 2331-5180
VL - 6
SP - 1
EP - 10
JO - International Journal of Particle Therapy
JF - International Journal of Particle Therapy
IS - 4
ER -