The primary purpose of this study is to determine if cross-linked hyaluronan gel reduces the dose of radiation delivered to the rectum and the rectal toxicity of radiotherapy for localized prostate cancer.

The main risk associated with transperineal injection of cross-linked hyaluronan gel into the anterior perirectal fat is infection. Prophylactic antibiotics will be given, resulting in a <5% risk. Another possible risk (<5%) is an allergic reaction such as itching. Patients who are allergic to avian products will be excluded from the study. Tenderness and pain at the injection site are possible. Bleeding, bruising, redness, or discoloration or the formation of a bump (granuloma) or scar (keloid) at the injection site is also possible. Embolization of cross-linked hyaluronan gel through the blood is a potential, rare complication if the gel is injected into a blood vessel rather than into fat. Prada et al. did not see any side effects related to the injection or the material itself in 27 patients based on a mean follow-up of 13 months (range: 9-22 months). Patients did not complain of pain, tenesmus, rectal pressure, or a sensation of rectal filling. Risks beyond 22 months are not well defined. Potential benefits of cross-linked hyaluronan gel include fewer rectal complications due to radiotherapy for early-stage prostate cancer.

Inclusion Criteria:

1. Histologically-confirmed adenocarcinoma of the prostate, clinical stage T1c-T2c, NX, N0, M0.
2. Nodes determined to be negative by imaging methods will be classified as NX. Only nodes determined to be negative by surgical sampling will be classified as N0.
3. Prostate cancer biopsy grading by Gleason score classification is mandatory.
4. No prior pelvic radiotherapy. Induction hormonal therapy for less than or equal to 6 months is acceptable.
5. Prostate volume by TRUS < 50 cc prior to HDR brachytherapy.
6. Prostate specific antigen (PSA) less than or equal to 30 ng/ml.
7. Patient has provided informed consent.

Exclusion Criteria:

1. Clinical stage T3 or T4.
2. Clinical evidence of lymph node involvement (N1).
3. Clinical evidence of distant metastases (M1).
4. Radical surgery for carcinoma of the prostate.
5. Allergy to avian products.
6. Significant mental, medical, or physical impairment.
7. Prisoners.
8. Employees of the Cancer Center of Irvine.