Radiation therapy for stage IIA and IIB XXXX : peripheral dose calculations and risk assessments.

@entity1 @entity249 @entity235 @entity5 @entity600 @entity4797 @entity65
UNASSIGNED: This study was conducted to calculate the peripheral dose to critical structures and assess the radiation risks from modern radiotherapy for stage IIA/IIB @entity4797 . A Monte Carlo code was used for treatment simulation on a computational phantom representing an average adult. The initial treatment phase involved anteroposterior and posteroanaterior modified @entity235 -leg fields exposing para-aortic and ipsilateral iliac lymph nodes followed by a cone-down phase for nodal mass irradiation. Peripheral doses were calculated using different modified @entity235 -leg field dimensions and an extended conventional @entity235 -leg portal. The risk models of the BEIR-VII report and ICRP-103 were combined with dosimetric calculations to estimate the probability of developing stochastic effects. Radiotherapy for @entity5 with a target dose of 30   Gy resulted in a range of 23.0-603.7   mGy to non-targeted peripheral tissues and organs. The corresponding range for treatment of stage IIB disease to a cumulative dose of 36   Gy was 24.2-633.9   mGy. A dose variation of less than 13% was found by altering the field dimensions. Radiotherapy with the conventional instead of the modern modified @entity235 -leg field increased the peripheral dose up to 8.2 times. The calculated heart doses of 589.0-632.9   mGy may increase the risk for developing @entity65 whereas the testicular dose of more than 231.9   mGy may lead to a temporary @entity249 . The probability of @entity600 in the offspring of @entity5 survivors was below 0.13% which is much lower than the spontaneous mutation rate. Abdominoplevic irradiation may increase the lifetime intrinsic risk for the induction of secondary @entity5 by 0.6-3.9% depending upon the site of interest, @entity1 's age and @entity5 dose. Radiotherapy for @entity5 with restricted fields and low doses is associated with an increased morbidity. These data may allow the definition of a risk-adapted follow-up scheme for long-term testicular @entity5 survivors.
