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Intensity-modulated radiation therapy (IMRT) for prostate cancer: Toxicity and biochemical control in 183 Chinese patients from a single institution in Hong Kong.

101 Background: To report the biochemical outcome and the acute and late toxicities in 183 Chinese patients with clinically localized prostate cancer treated with IMRT.


METHODS
Between May 2001 and November 2009, 183 patients with clinically localized prostate cancer were treated with IMRT at the Prince of Wales Hospital. Median follow-up was 44 months (range 8.5 to 112 months).Treatment was planned using an inverse-planning approach, and the beams were delivered by dynamic multileaf collimation. Four-field box technique was used for pelvic irradiation (pelvic RT) if indicated in phase I and IMRT was used for prostate boost in phase II. The median age of the patients was 71.4 (range 45 to 82). According to the NCCN risk classification, 18 (9.8%), 47 (25.7%) and 118 (64.5%) patients belong to favorable, intermediate, and unfavorable risk group respectively. The median prescription dose of the planning target volume of the prostate gland (PTV-G) is 72Gy (range from 66 to 76Gy). 77 patients (42.1%) received pelvic RT. 129 patients (70%) received neoadjuvant hormone and 106 patients (57.9%) received adjuvant hormone. Acute and late toxicities were scored according to the Common Terminology Criteria for Adverse Events Version 4.02. Biochemical failure was defined according to the Houston definition (absolute PSA nadir plus 2ng/ml dated at the call).


RESULTS
The 5-year actuarial biochemical-failure free survival for patients in favorable, intermediate and unfavorable risk groups were 95%, 80%, and 83% respectively. 3 patients (1.6%) experienced grade 3 acute gastrointestinal (GI) toxicity. There were no grade 3 acute genitourinary (GU) toxicity. There was no grade 4 acute GI or GU toxicity. 14 patients (7.7%) developed grade 2 late GI toxicity and 8 patients (4.4%) developed grade 3 late GI toxicity. 5 patients (2.7%) developed grade 2 late GU toxicity and 5 patients (2.7%) developed grade 3 late GU toxicity. There was no grade 4 late GI or GU toxicity.


CONCLUSIONS
These data demonstrate that IMRT for prostate cancer is feasible and safe in Chinese population. The early biochemical outcome is encouraging and the grade 3 late GI and GU complications were below 5%. No significant financial relationships to disclose.