Learning Curve in the Application of a Hydrogel Spacer to Protect the Rectal Wall During Radiotherapy of Localized Prostate Cancer

摘要: Objective To evaluate the effect of increasing experience on hydrogel dimensions, rectal dose, and acute toxicity, to discuss important technical issues gained from this experience. Methods Sixty-four consecutive patients with prostate cancer were included in analysis (G1/G2 corresponding first/second 32 patients) after injection 10 mL spacer gel. All treated a 5-field intensity-modulated radiotherapy technique 76-78 Gy. Treatment toxicity was evaluated validated quality life questionnaire (expanded index composite) before radiotherapy. Results Rectum volume could be entirely excluded planning target 31% G1 vs 56% G2 (P = .04). Increasing symmetry detected comparing first 15 subsequent rest, mean differences between right left 0.6 cm 0.3 at midgland .03). Mean distance anterior wall increased 0.8 cm/1.1 cm/0.8 (G1) base/middle/apex 1.3 cm/1.5 cm/1.2 (G2), respectively, so that dose rectum decreased significantly (6% 2% inside 70 Gy isodose; P <.01). Bowel function bother score changes smaller baseline last day levels (mean 16/18 9/12 G2). Conclusion A learning curve demonstrated our patient population, respecting improved more symmetrical placement, treatment planning, less treatment-related toxicity. Several aspects need considered.