Purpose To determine if local recurrence of prostate cancer after radiation therapy occurs at the same site as the primary tumor before treatment, using longitudinal MR imaging and MR spectroscopic imaging to assess dominant tumor location. Materials and Methods This retrospective study was HIPAA compliant and approved by our Committee on Human Research. We identified all patients in our institutional prostate cancer database (1996 onwards) who underwent endorectal MR imaging and MR spectroscopic imaging before radiotherapy for biopsy-proven prostate cancer and again at least 2 years after radiotherapy (n = 124). Two radiologists recorded the presence, location, and size of unequivocal dominant tumor on pre- and post-radiotherapy scans. Recurrent tumor was considered to be at the same location as the baseline tumor if at least 50% of the tumor location overlapped. Clinical and biopsy data was collected on all patients. Results Nine patients had unequivocal dominant tumor on both pre- and post-radiotherapy imaging, with mean pre- and post-radiotherapy dominant tumor diameter of 1.8 cm (range, 1 to 2.2) and 1.9 cm (range, 1.4 to 2.6), respectively. The median follow-up interval was 7.3 years (range, 2.7 to 10.8). Dominant recurrent tumor was at the same location as dominant baseline tumor in 8 of the 9 patients (89%). Conclusion Local recurrence of prostate cancer after radiation usually occurs at the same site as the dominant primary tumor at baseline, suggesting supplementary focal therapy aimed at enhancing local tumor control would be a rational addition to management.

Empiric arterial embolization may be advantageous in patients with a duodenal source of hemorrhage but not in patients with gastric hemorrhage.