ABSTRACT
In recent years, the incidence rate of prostate cancer has been gradually elevated year by year in China. External radiotherapy yields similar clinical efficacy to surgery in the treatment of localized prostate cancer. Because the rectum is close to the prostate, the radiotherapy targeting for prostate cancer constantly causes radiation-related proctitis. Recently, multiple researchers have attempted to inject polyethylene glycol hydrogel into the rectal prostate space to separate the rectum from the prostate, thereby reducing the radiation dose coverage for the rectum and minimizing the risk of radiation-related proctitis. In this article, the application basis, radiation stability, injection technology, dosimetry and clinical efficacy of polyethylene glycol hydrogel injection were summarized.
ABSTRACT
Objective To compare the efficacy and adverse effects of hypofractionated radiotherapy versus conventionally fractionated radiotherapy for intermediate-to high-risk localized prostate cancer.Methods A literature search was performed in PubMed, Embase, Web of Science, CNKI, VIP database, and Wanfang Data to collect the controlled clinical trials of hypofractionated radiotherapy versus conventionally fractionated radiotherapy in patients with intermediate-to high-risk localized PCa published up to August 31, 2016.Stata 12.0 was used for meta-analysis.The difference between two groups was estimated by calculating the hazard ratio (HR) or risk ratio (RR) with 95%confidence interval (CI).ResultsAccording to the inclusion and exclusion criteria, a total of 5 controlled clinical trials involving 1621 patients with PCa were included in this meta-analysis.The meta-analysis showed that overall survival (HR=1.00, 95%CI:0.85-1.17, P=0.980) and biochemical failure (RR=0.87, 95%CI:0.68-1.12, P=0.274) were comparable between the two groups.Compared with the conventionally fractionated radiotherapy, the incidence of acute gastrointestinal adverse events (grade≥2) was significantly higher in the hypofractionated radiotherapy (RR=1.94, 95%CI:1.23-3.06, P=0.004).However, there were no significant differences in the incidence of acute genitourinary adverse events (grade≥2)(RR=1.03, 95%CI:0.92-1.14,P=0.626), late gastrointestinal adverse events (grade≥2)(RR=1.17,95%CI:0.90-1.51, P=0.238), and late genitourinary adverse events (grade≥2)(RR=1.11, 95%CI:0.94-1.30, P=0.228) between the two groups.Conclusions Conventionally fractionated radiotherapy and hypofractionated radiotherapy have comparable therapeutic effects in patients with intermediate-to high-risk localized PCa.Although the patients treated with hypofractionated radiotherapy have a higher incidence of acute gastrointestinal adverse events than those treated with conventionally fractionated radiotherapy, the incidence of late gastrointestinal and genitourinary adverse events is comparable between the two groups of patients and the adverse effects are tolerable.
ABSTRACT
Objective To study the relationship between changes in prostate volume and neoadjuvant hormone therapy ( NHT) duration in prostate cancer radiotherapy. Methods Fifty patients with prostate cancer who received NHT were enrolled in the study continuously. The diameters along the x?, y?, and z?axes of the prostate were measured, and the volume of prostate was calculated weekly during radiotherapy. The relationship of prostate volume reduction with NHT duration, prostate volume before radiotherapy, and prostate cancer risk groups was analyzed during radiotherapy. Results The prostate volume in all patients decreased after radiotherapy. Patients with short NHT duration had larger changes in prostate volume and diameters than those with long NHT duration. Compared with those with a large prostate volume, patients with a normal prostate volume had larger changes in prostate volume and diameters long three axes after 7 weeks of radiotherapy, shorter NHT duration before radiotherapy, and lower risk of prostate cancer. In patients with low?and medium?risk prostate cancer, the prostate volumes were significantly reduced to 68?10% and 78?70%, respectively, of those before radiotherapy after no more than 4 months of NHT ( P=0?002) , but remained similar after more than 4 months of NHT. In patients with high?risk and more severe prostate cancer, the prostate volumes were significantly reduced to 76?59% and 85?46%, respectively, of those before radiotherapy after no more than 6 months of NHT (P=0?001), but remained similar after more than 6 months of NHT. Conclusions The changes in prostate volume and diameters along three axes during radiotherapy become smaller with longer NHT duration. Patients with low?or medium?risk prostate cancer have slight changes in prostate volume after more than 4 months of NHT, while patients with high?risk or locally advanced prostate cancer have slight changes in prostate volume after more than 6 months of NHT.
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Objective To analyze the acute and late toxicities in patients with prostate cancer trea-ted with hypofractionated intensity-modulated radiotherapy (IMRT). Methods Between June 2006 and June 2008, 37 patients with prostate cancer were treated with hypofractionated IMRT. The clinical target vol-ume (CTV) was the prostate, seminal vesicles and pelvic lymph nodes in 24 patients, the prostate and semi-hal vesicles in 12, and only the tumor bed in 1. The dose per fraction was 2.3 - 2.8 Gy, with 2.7 Gy in 26 patients. The minimal dose was 62.5-75.0 Gy to the prostate and seminal vesicles, and 50 Gy to the pelvic lymph nodes. Results The median follow-up was 14 months. None of the patients experienced grade 4 a-cute gastro-intestinal (GI) toxicity. Grade 1, 2 and 3 acute GI toxicity occurred in 24.3%, 35.1% and 2.7% of the patients, respectively. The rectal V50>27% and V55>20% were highly significantly associat-ed with grade ≥1 acute GI toxicity. Grade 1,2 and 3 acute genitourinary (GU) toxicity occurred in 68%, 0% and 3% of the patients, respectively. The bladder V50> 10% was significantly associated with grade ≥1 acute GU toxicity. The incidence of late GI toxicity was low. No grade ≥3 late GI toxicity was observed. The incidence of late grade 1 and 2 GI toxicity was 24% and 5%, respectively. The rectal V65> 10% was highly significantly associated with grade ≥1 late GI toxicity. No late grade 4 GU toxicity was observed. The incidence of grade 1, 2 and 3 late GU toxicity was 49%, 11% and 3%, respectively. Grade ≥2 late GU toxicity was correlated with V40, V50 and mean dose of the bladder. Conclusions Acute and late toxicity of hypofractionated IMRT is acceptable in patients with prostate cancer.
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Objective On basis of physical dose optimization, LQ model was used to investigate the difference between the curves of biological effective dose and physical isodose. The influence of applying the biological dose concept on three dimensional conformal radiotherapy of prostate carcinoma was discussed. Methods Four treatment plannings were designed for physical dose optimization: three fields, four-box fields, five fields and six fields. Target dose uniformity and protection of the critical tissue -rectum were used as the principal standard for designing the treatment planning. Biological effective dose (BED) was calculated by LQ model. The difference between the BED curve drawn in the central layer and the physical isodose curve was studied. The difference between the adjusted physical dose (APD) and the physical dose was also studied. Results Five field planning was the best in target dose uniformity and protection of the critical tissue -rectum. The physical dose was uniform in the target, but the biological effective doses revealed great discrepancy in the biological model. Adjusted physical dose distribution also displayed larger discrepancy than the physical dose unadjusted. Conclusions Intensified Modulated Radiotherapy (IMRT) technique with inversion planning using biological dose concept may be much more advantageous to reach a high tumor control probability and low normal tissue complication probability.
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Objective To evaluate the outcome and prognosis of prostate carcinoma treated with three-dimensional conformal radiation therapy(3DCRT). Methods From 2000 to 2004,37 patients were so treated. Two patients have been lost to follow up. Twenty-four patients underwent orchiectomy before 3DCRT,20 patients received chemotherapy combined with hormone therapy and 4 received radiation castration. All patients were treated with a median dose of 72Gy(60-76Gy),2Gy/f ,5 fractions/w. Results With a median follow-up time of 27 months(6-107months),the 3- and 5-year survival rate was 80% and 70%, respectively. Longrank analysis showed age, PSA level before treatment, lymph node metastasis, distant metastasis, total dose and combined modality were prognostic factors for the survival. Cox model multivariate analysis showed PSA level before treatment, total dose and combined modality were prognostic factors for the survival. Conclusions The outcome of three-dimensional conformal radiation therapy for T2-T4 prostate carcinoma is safe and effective with tolerable side effects. PSA level before treatment, total dose and combined modality are prognostic factors for the survival.