Interactive-plan technique conquers the disadvantages of volume-reducing hormone therapy in 125I permanent implantation for localized prostate cancer.

BACKGROUND

The purpose of this study was to assess the impact of hormone therapy on post-implant dosimetry in patients in whom pre-plan and interactive-plan techniques were used for transperineal brachytherapy against prostatic cancer.

METHODS

The subjects comprised 244 patients treated using (125)I seed implantation as monotherapy. The prescribed dose to the periphery of the prostate was 145 Gy. The pre-plan technique was used for 116 patients, and the interactive-plan technique for 128 patients. Hormone therapy was used in 71 patients (29.1%). The D90 (dose to 90% of prostate volume) of post-implant computed tomography (CT) analysis was assessed in both groups. In addition, the ratio of post-implant CT volume to preoperative ultrasonography (US) volume was assessed.

RESULTS

In the pre-plan group, D90 was significantly lower for patients who received hormone therapy than for those who did not (P = 0.035). However, in the interactive-plan group, D90 did not differ between patients with and without hormone therapy (P = 0.467). The CT-to-US prostate volume ratio was 1.022 for patients who received hormone therapy and 0.960 for patients who did not (P = 0.021).

CONCLUSION

Post-traumatic swelling following implantation is increased by cessation of hormone therapy and may reduce D90. However, the present results suggest that the interactive-plan technique overcomes this disadvantage of hormone therapy.