Assessment of the second cancer risk after Prostate Cancer Treatment: comparison of 3D conformal radiotherapy and Intensity Modulated Radiotherapy

Document Type : Original Paper

Authors

1 Physics Department, Faculty of Science, Al-Azhar University, Nasr City, Cairo 11884, Egypt

2 Radiotherapy Department, National Cancer Institute, Faculty of Medicine, Cairo University, Giza, Egypt

Abstract

Introduction: Radiation-induced secondary primary cancer is one of the significant late side effects and an undesired outcome of radiotherapy that can be observed in long-term cancer survivors. The present study aimed to estimate the risk of second cancer risk after Three-dimensional conformal radiotherapy (3DCRT) and intensity modulated radiotherapy (IMRT) for early stage prostate cancer patient.

Material and Methods: In this study, 10 patients with early stage prostate cancer have been chosen. Three-dimensional conformal radiotherapy (3DCRT), intensity-modulated radiotherapy (IMRT) plans were designed. The organ equivalent dose (OED) was calculated based on linear, linear-exponential, and plateau dose-response models. The Second cancer risks (SCR) were estimated by Excess absolute risk (EAR).

Results: The target dose coverage parameters were significantly improved in IMRT compared to 3DCRT. The rectum and bladder mean dose DMean, V50Gy% and V40Gy % were significantly decreased with IMRT. The maximum dose (DMax), DMean, V30Gy % and V20Gy % for head of femurs significantly decreased with IMRT plans. However, the colon DMean significantly increased with in IMRT compared with 3DCRT. The IMRT plans were decreased SCR for the rectum by 10%, 26.6% and 19.5% for linear, plateau and linear-exponential dose- response models respectively. The bladder second cancer risk was decreased by 14% with linear dose-response model in comparison to 3DCRT plans. However, the second cancer risk for colon was significantly increased in average by 91.2% with IMRT plans.

Conclusion: IMRT technique demonstrated a clear advantage in dose coverage, conformity, and homogeneity over 3DCRT and was superior in terms of OAR-sparing. The Second cancer risk for in field organs (rectum and bladder) was decreased with IMRT compared 3DCRT plan.

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Articles in Press, Accepted Manuscript
Available Online from 10 January 2022
  • Receive Date: 15 August 2021
  • Revise Date: 02 January 2022
  • Accept Date: 10 January 2022
  • First Publish Date: 10 January 2022