ABSTRACT
PURPOSE: Single-institution single-arm prospective study. Endpoint: To assess whether there are more than 5 % of men having grade 3 GU or any grade 3 GI acute toxicity during stereotactic body radiation therapy (SBRT) for prostate cancer using helical tomotherapy. METHODS: Since May 2012, 17 prostate cancer patients were treated with helical tomotherapy. The exclusion criteria used are the following: Gleason score ≥8, PSA >20 ng/ml, cT3b-4, IPSS ≥20 and history of acute urinary retention. CTV included the prostate gland and 1 cm of seminal vesicles in the low-risk group (LR) or the seminal vesicles completely in the intermediate (IR) and high-risk (HR) NCCN groups. CTV margins ranged from 2 to 8 mm, while PTV margins were 2 to 9 mm. Patients received eight fractions of 5.48 Gy (LR) or 5.65 Gy (IR, HR) on alternate days. Total equivalent doses at 2 Gy per fraction are 87.4 for LR and 92.3 Gy for IR-HR using an α/ß value of 1.5. Correspondent figures for a α/ß of 3 are 74.3 Gy and 78.2 Gy, respectively. Megavoltage CT (MVCT) for on-line correction was taken before every fraction. RESULTS: The patient distribution by risk group is 29, 47 and 24 % for LR, IR and HR, respectively. 82 % received neoadjuvant-concomitant hormonal therapy. Acute GU toxicity grade 1, 2 and 3 was found in 70, 6 and 0 % of men. GI toxicity was observed in 50, 0 and 0. After 136 MVCT, the standard deviation of the mean individual corrections in the anterior-posterior direction was 2.5 mm. CONCLUSION: SBRT for prostate cancer using helical tomotherapy is feasible. Initial results show an early toxicity profile no worse than SBRT delivered with robotic radiosurgery or conventionally fractionated radiotherapy.
Subject(s)
Prostatic Neoplasms/radiotherapy , Radiosurgery/adverse effects , Radiosurgery/methods , Radiotherapy, Intensity-Modulated/adverse effects , Aged , Humans , Male , Middle Aged , Risk FactorsABSTRACT
PURPOSE: To prospectively study acute genitourinary (GU) and gastrointestinal (GI) toxicity during hypofractionated radiotherapy. PATIENTS AND MATERIALS: One-hundred and seventy-one consecutive men with cT1-T3cN0cM0 prostate cancer were treated at 2.6 Gy/fraction to a total dose of 67.6 for low risk (EQD2 = 79 Gy) and 70.2 Gy for intermediate-high risk (EQD2 = 82 Gy) over 5.2-5.4 weeks (α/ß 1.5). Acute toxicity was scored according to RTOG/EORTC toxicity extended criteria after completing a 22-item questionnaire (basal, weekly, at 6 months). RESULTS: Minimum and median follow-up were 36 and 54.2 months, respectively. GU toxicity grades 0, 1, 2 and 3 were found in 30.4, 37, 32 and 0.6 % of patients, respectively. The figures for grades 0, 1, 2 and 3 GI toxicity were 66, 24, 10 and 0 %. The highest degree of acute reactions was reached at 4-5 weeks. At 6 months, 15 % of patients had GU toxicity (11 % grade 1, 4 % grade 2) and 5.8 % GI toxicity (5.3 % grade 1, 0.5 % grade 2). Multivariate analysis shows that bladder volume receiving ≥65 Gy (V 65) is associated with an increased risk of GU complications (p = 0.017, HR = 1.143, 95 % CI = 1.025-1.276), while history of TURP is linked to lower risk (p = 0.002, HR = 0.310, 95 % CI 0.004-0.370). Mean rectal dose (p = 0.013, HR = 1.089, 95 % CI 1.018-1.116) and total dose (p = 0.019, HR = 0.734, 95 % CI 0.567-0.950) are significantly related to GI toxicity. CONCLUSIONS: This 5-week dose-escalation hypofractionated radiotherapy schedule that uses 3D-conformal radiotherapy without IGRT has resulted in <1 % grade 3 acute complications. Our study suggests that reducing the mean rectal dose and the bladder V 65 helps prevent acute toxicity. TURP before radiotherapy was associated with lower acute GU toxicity.
