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The aim of the present study was to evaluate the efficacy and safety of intensity-modulated radiation therapy (IMRT) for elderly patients with prostate cancer (age ≥75 years) compared with younger patients (<75 years). The numbers of patients enrolled into the elderly and younger groups were 238 and 853, respectively. More than half of the patients in the elderly group were high-risk, and the total risk of the elderly group was higher than that of younger group. The median follow-up periods for the elderly and younger groups were 42 (range, 2-108) and 49 (range, 2-120) months, respectively. All patients were treated with IMRT at a dose of 74-78 Gy with or without androgen-deprivation therapy. The biochemical failure-free rates (BFFRs) at 3-year follow-up for the elderly and younger groups were 93.3 and 95.7%, respectively; there was no significant difference between the 2 groups in regard to the BFFR. The clinical failure-free rates (CFFR) at 3-year follow-up for the elderly and younger groups was 95.8 and 98.5%, respectively; the 2 groups did not differ significantly in regard to the CFFR. The cumulative incidence rates of gastrointestinal toxicity (grade ≥2) and genitourinary toxicity (grade ≥2) at 3-year follow-up were 10.5 and 1.3%, respectively; there was no significant difference between the elderly and younger groups. It was concluded that in prostate cancer patients aged 75 years or older, IMRT has a treatment effect equivalent to that in patients <75 years old; adverse events are also comparable.
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AIM: To define the optimal margin on MRI scans in the re-radiation planning of recurrent glioblastoma using methionine positron emission tomography (MET-PET). BACKGROUND: It would be very useful if the optimal margin on MRI to cover the uptake area on MET-PET is known. MATERIALS AND METHODS: CT, MRI, and MET-PET were performed separately over the course of 2 weeks. Among the MRI scans, we used the contrast-enhanced T1-weighted images (Gd-MRI) and T2-weighted images (T2-MRI). The Gd-MRI-based clinical target volume (CTV) (CTV-Gd) and the T2-MRI-based CTV (CTV-T2) were defined as the contrast-enhanced area on Gd-MRI and the high intensity area on T2-MRI, respectively. We defined CTV x mm (x = 5, 10, 15, 20) as x mm outside the CTV. MET-PET-based CTV (CTV-MPET) was defined as the area of accumulation of MET-PET. We calculated the sensitivity and specificity of CTV-Gd and CTV-T2 following comparison with CTV-MPET, which served as the gold standard in this study. RESULTS: The sensitivity of CTV-T2 5 mm (98%) was significantly higher than CTV-T2 (87%), and there was no significant difference in the sensitivity between CTV-T2 5 mm and CTV T2 10, 15, or 20 mm. The sensitivity of CTV-Gd 20 mm (97%) was lower than that of CTV-T2 5 mm (98%). CONCLUSIONS: A margin of at least 5 mm around the high intensity area on T2-MRI is necessary in the target volume delineation of recurrent glioblastoma for the coverage of MET-PET findings in re-radiation therapy planning.
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AIM: This study aimed to evaluate the treatment result of intensity-modulated radiation therapy (IMRT) in a large number of Japanese patients with prostate cancer. BACKGROUND: A total of 1091 patients with localized prostate cancer were recruited between March 2006 and July 2014. The patients were stratified into low- (n = 205 [18.8%]), intermediate- (n = 450 [41.2%]), high- (n = 345 [31.6%]), and very high-risk (n = 91 [8.3%]) groups according to the National Comprehensive Cancer Network classification. All patients were irradiated via IMRT at a dose of 74-78 Gy with or without androgen-deprivation therapy. The mean follow-up period was 50 months (range, 2-120 months). RESULTS: The biochemical failure-free rate (BFFR), the clinical failure-free rate, and the overall survival rate at the 5-year follow-up for all patients was 91.3%, 96.2%, and 99.1%, respectively. In univariate analysis, the prostate-specific antigen (PSA) levels (≤20 vs. >20 ng/ml) were significantly correlated with BFFR. A trend toward higher BFFR was noted in patients with a Gleason score (GS) of ≤7 than in patients with GS ≥8. In multivariate analysis, only PSA (≤20 vs. >20 ng/ml) was significantly correlated with BFFR. The cumulative incidence rate of gastrointestinal and genitourinary toxicity (≥grade 2) at the 5-year follow-up was 11.4% and 4.3%, respectively. CONCLUSIONS: The findings of this study indicate that IMRT is well tolerated and is associated with both good long-term tumor control and excellent outcomes in patients with localized prostate cancer.
RESUMEN
AIM: To assess the changes in prostate size in patients with prostate cancer undergoing intensity-modulated radiation therapy (IMRT). BACKGROUND: The effect of size change produced by IMRT is not well known. MATERIALS AND METHODS: We enrolled 72 patients who received IMRT alone without androgen-deprivation therapy and underwent magnetic resonance imaging (MRI) examination before and after IMRT. The diameter of the entire prostate in the anterior-posterior (P-AP) and left-right (P-LR) directions was measured. The transitional zone diameter in the anterior-posterior (T-AP) and left-right (T-LR) directions was also measured. RESULTS: The average relative P-AP values at 3, 6, 12, 24, and 36 months after IMRT compared to the pre-IMRT value were 0.94, 0.90, 0.89, 0.89, and 0.90, respectively; the average relative P-LR values were 0.93, 0.92, 0.91, 0.91, and 0.90, respectively. The average P-AP and P-LR decreased by approximately 10% during the 12 months post-IMRT, and remained unchanged thereafter. The average relative T-AP values at 3, 6, 12, 24, and 36 months after IMRT compared to the pre-IMRT value were 0.93, 0.88, 0.91, 0.87, and 0.89, respectively; the average relative T-LR values were 0.96, 0.90, 0.91, 0.87, and 0.88, respectively. The average T-AP and T-LR also decreased by approximately 10% during the 12 months post-IMRT, and remained unchanged thereafter. At 12 months after IMRT, the average relative T-AP was significantly lower in patients with recurrence than in those without recurrence. CONCLUSIONS: The average prostate diameter decreased by approximately 10% during the 12 months after IMRT; thereafter remained unchanged.