Login to Access Video or Poster Abstract: MP05-14
Sources of Funding: None

Introduction

External beam radiation therapy is a common modality for prostate cancer, although acute and chronic side effects remain significant. Radiofrequency tracking beacons allow for real-time tracking of the prostate using 3 non-coplanar markers and intrafraction monitoring of prostate position and is one modality of image guidance that may help to decrease local radiation exposure._x000D_ _x000D_ This study retrospectively evaluated the acute and chronic morbidities of radiofrequency tracking beacons vs CBCT radiotherapy.

Methods

This is a IRB-approved single center retrospective review of patients who presented to St. Elizabeth Hospital for radiofrequency tracking beacons or CBCT for prostate cancer during April 2010 - December 2011. Inclusion criteria were T1/T2 prostate cancer without prior radiation, prostatectomy, or brachytherapy. A total of 191 patient charts were reviewed and 131 patients were included: 55 cone-beam and 76 beacons transponders. Short-term and long-term morbidites were recorded: short-term were defined as under two years and long-term was defined as lasting or beginning greater than two years after treatment. These toxicities were graded using the Radiation Therapy Oncology Group (RTOG) toxicity grading system. Significance was set as p<0.05 and analyzed using single variate analysis.

Results

There were no significant differences between age, Gleason score, starting PSA, and use of anti-androgens between the treatment_x000D_ groups. The short term morbidities of CBCT vs radiofrequency tracking beacons were_x000D_ significantly different (p<0.01) at 27.3% and 59.2%, respectively._x000D_ Nocturia (p<0.01) and hematuria (p=0.05) were significantly higher in the radiofrequency beacons. Long-term morbidities of CBCT vs tracking beacons were_x000D_ not significant (p=0.59) with values of 5.5% vs 7.9%. There were no_x000D_ significant differences in biochemical cancer recurrence._x000D_

Conclusions

For short-term morbidities, beacons transponders patients experienced side effects significantly more than CBCT patients, particularly those of nocturia and hematuria._x000D_ This may be due to irritation from beacon placement and increased radiation dosage when using beacons transponders._x000D_ _x000D_ The long-term morbidities correlate with current literature as there were no significant differences in biochemical cancer recurrence and long-term morbidities between standardly used radiation modalities. This study suggests that beacons transponders do not decrease the amount of radiation associated short-term morbidities._x000D_

Funding

None