A Study of Adaptive Radiation Therapy for Pelvic Genitourinary Cancer

A Study of Adaptive Radiation Therapy for Pelvic Genitourinary Cancer

Radical radiation therapy for prostate cancer is a common treatment that has shown to improve clinical outcomes in a post-operative setting. However, radiation therapy after surgery poses a greater risk for bladder and rectum injury for patients with prostate or bladder cancer. For prostate cancer patients, the risk is further amplified when pelvic nodes are part of the target irradiated volume. For bladder cancer patients, the risk of injury increases when more of the bladder is part of the target volume. Using an adaptive radiation therapy approach allows for correcting any shifts in the target volume. ART approach uses images from treatment to adapt the treatment plan. This study will use Adaptive Radiation Therapy for patients who receive pelvic nodal radiotherapy for either prostate or bladder cancer. Their treatment plans will adapted using MRI scans and CBCT scans taken during their first week of radiotherapy to account for any shifts in the target volume. The purpose of this study is to evaluate the feasibility of ART approach and its and on treatment plan quality metrics for pelvic radiotherapy. Acute and late toxicities will also be evaluated. 40 participants (minimum of 10 bladder cancer patients) will be enrolled. The participants will be followed for a period of 5 years post radiation therapy, during which they will have PSA as per standard practice, along with follow-up questionnaires (EPIC for prostate cancer patients and BUSS for bladder cancer patients).

Inclusion Criteria:

1. Histologic diagnosis of adenocarcinoma of the prostate after radical prostatectomy:

   • Clinical stage pT3, pT4, or pT2 with positive margin; OR,
   • any p-stage with persistently elevated post-operative PSA > 0.05ng/mL; OR,
   • a delayed rise in PSA post-operative

2. Histologic diagnosis of transitional cell carcinoma of the bladder with intact bladder and:

   • Clinical stage cT2, cT3, cT4, and N0 or N1

Exclusion Criteria:

1. Inflammatory bowel disease or other contraindications to radiotherapy.
2. Prior pelvic radiotherapy
3. Previous cytotoxic chemotherapy
4. Evidence of systemic metastases on imaging