Application of a hydrogel spacer for postoperative salvage radiotherapy of prostate cancer

• Published in: Strahlentherapie und Onkologie 2015-04, Vol.191 (4), p.375-379
• Main Authors: Pinkawa, Michael, Schubert, Carolin, Escobar-Corral, Nuria, Holy, Richard, Eble, Michael J.
• Format: Article
• Language: English
• Subjects: Aged; Case Report; Dose Fractionation; Humans; Hydrogel, Polyethylene Glycol Dimethacrylate; Male; Materials Testing; Medicine; Medicine & Public Health; Neoplasm, Residual; Oncology; Postoperative Care - instrumentation; Postoperative Care - methods; Prostatic Neoplasms - radiotherapy; Prostheses and Implants; Radiation Protection - instrumentation; Radiotherapy; Radiotherapy, Adjuvant - instrumentation; Radiotherapy, Adjuvant - methods; Radiotherapy, Conformal - instrumentation; Radiotherapy, Conformal - methods; Salvage Therapy - instrumentation; Treatment Outcome
• ISSN: 0179-7158; 1439-099X
• DOI: 10.1007/s00066-014-0769-z

Background In contrast to primary radiotherapy, no reports are available for a hydrogel spacer application in postoperative salvage radiotherapy for prostate cancer. Case report A 77-year-old patient presented 20 years after radical prostatectomy with a digitally palpable local recurrence at the urethrovesical anastomosis (PSA 5.5 ng/ml). The hydrogel spacer (10 ml, SpaceOAR TM ) was injected between the local recurrence and rectal wall under transrectal ultrasound guidance. Treatment planning was performed with an intensity-modulated technique up to a total dose of 76 Gy in 2-Gy fractions. The same planning was performed based on computed tomography before spacer injection for comparison. Results The local recurrence, initially directly on the rectal wall, could be displaced more than  1 cm from the rectal wall after hydrogel injection. With a mean total dose of 76 Gy to the planning target volume, rectal wall volumes included in the 70 Gy, 60 Gy, 50 Gy isodoses were 0 cm 3 , 0 cm 3 , and 0.4 cm 3 with a spacer and 2.9 cm 3 , 4.5 cm 3 , and 6.2 cm 3 without a spacer, respectively. The patient reported rectal urgency during radiotherapy, completely resolving after the end of treatment. The PSA level was 5.4 ng/ml a week before the end of radiotherapy and dropped to 0.9 ng/ml 5 months after radiotherapy. Conclusion A hydrogel spacer was successfully applied for dose-escalated radiotherapy in a patient with macroscopic local prostate cancer recurrence at the urethrovesical anastomosis to decrease the dose at the rectal wall. This option can be considered in specifically selected patients.