External Beam Radiotherapy Dose Research Articles

Californium versus cobalt brachytherapy combined with external-beam radiotherapy for IIB stage cervical cancer: long-term experience of a single institute.

PurposeThe purpose of this paper was to observe and compare long-term curative effects and complications of FIGO stage IIB cervical cancer patients (n = 232) treated with high-dose-rate (HDR) californium (252Cf) neutron or cobalt (60Co) photon intracavitary brachytherapy (ICBT) combined with external-beam radiotherapy (EBRT).Material and methodsThe EBRT dose to the small pelvis was 50 Gy in both groups. The brachytherapy component of 252Cf or 60Co was added in the 3rd week of EBRT, 5 fractions were performed once per week resulting in a total ICBT dose of 40 Gy/Gyeq (point A).ResultsOverall survival (OS) at 5, 10 and 15 years was 63.6%, 50.4% and 38.8% in the 252Cf group and 62.2%, 50.5%, 39.9%, in the 60Co group, respectively (p = 0.74). The percentage of tumour recurrence was statistically significantly lower in the 252Cf group with 7.4% versus 17.1% in the 60Co group (p = 0.02). Second primary cancers have developed similarly 9.1% and 8.1% cases for 252Cf and 60Co groups, respectively.ConclusionsOur long-term retrospective study comparing 252Cf and 60Co isotopes with brachytherapy in combined treatment of FIGO IIB stage cervix carcinoma patients shows, that overall survival in the both groups are similar. However, the recurrence of tumour was significantly lower in the 252Cf group. The incidence of second primary cancers was similar in both groups.

Interstitial high-dose rate brachytherapy as boost for anal canal cancer.

AimTo assess clinical outcomes of patients treated with a high-dose rate brachytherapy boost for anal canal cancer (ACC).MethodsFrom August 2005 to February 2013, 28 patients presenting an ACC treated by split-course external beam radiotherapy (EBRT) and HDR brachytherapy with or without chemotherapy in a French regional cancer center in Nice were retrospectively analyzed.ResultsMedian age was 60.6 years [34 – 83], 25 patients presented a squamous cell carcinoma and 3 an adenocarcinoma; 21 received chemotherapy. Median dose of EBRT was 45 Gy [43.2 – 52]. Median dose of HDR brachytherapy was 12 Gy [10 - 15] with a median duration of 2 days. Median overall treatment time was 63 days and median delay between EBRT and brachytherapy was 20 days. Two-year local relapse free, metastatic free, disease free and overall survivals were 83%, 81.9%, 71.8% and 87.7% respectively. Acute toxicities were frequent but not severe with mostly grade 1 toxicities: 37% of genito-urinary, 40.7% of gastro-intestinal and 3.7% of cutaneous toxicities. Late toxicities were mainly G1 (43.1%) and G2 (22%). Two-year colostomy-free survival was 75.1%, one patient had a definitive sphincter amputation.ConclusionHigh-dose rate brachytherapy for anal canal carcinoma as boost represents a feasible technique compared to low or pulsed-dose rate brachytherapy. This technique remains an excellent approach to precisely boost the tumor in reducing the overall treatment time.

P043 Matched pair study to assess the quality of life and toxicity in patients with carcinoma of the prostate undergoing external beam radiotherapy plus high dose rate brachytherapy boost compared with patients receiving conformal external beam radiotherapy alone

P043 Matched pair study to assess the quality of life and toxicity in patients with carcinoma of the prostate undergoing external beam radiotherapy plus high dose rate brachytherapy boost compared with patients receiving conformal external beam radiotherapy alone

Salvage radiation therapy with combined external beam radiation and high dose rate brachytherapy for isolated vaginal recurrences of endometrial cancer for patients without prior radiation treatment

Salvage radiation therapy with combined external beam radiation and high dose rate brachytherapy for isolated vaginal recurrences of endometrial cancer for patients without prior radiation treatment

Improvement in treatment results of glioblastoma over the last three decades and beneficial factors

Background. The purpose of this study is to elucidate the trend of glioblastoma outcome and scrutinize the factors contributing to better outcome over three decades. Methods. Survival time and the influencing factors were retrospectively analyzed in 223 newly diagnosed primary glioblastoma patients during 1980–2010. Appraised factors included age, sex, tumor site, year of surgery, extent of resections, use of surgery supporting system, Karnofsky Performance Status (KPS), chemotherapy, conventional external beam radiotherapy (EBRT), and CyberKnife stereotactic radiotherapy (CK-SRT) use. Results. The median survival time (MST) in all patients was 13.6 months. The MSTs for 4 periods were 9.8 (1980–1990), 13.7 (1991–2000), 12.9 (2001–2005), and 15.8 months (2006–2010), respectively (p = 0.0047). Total resection, subtotal resection, partial resection, and biopsy had MSTs of 31.8, 13.9, 11.4, and 7.0 months, respectively (p < 0.0001). Regarding chemotherapy, MSTs of the temozolomide base group and nimustine hydrochloride (ACNU) base group were 16.9 and 14.6 months, respectively, whereas the MST of patients without chemotherapy was only 9.8 months (p < 0.0001). The MSTs for 40-Gy EBRT plus CK-SRT and 60-Gy EBRT were 19.1 and 10.7 months, respectively (p < 0.0001). But in sub-selected patients, treated during 2001–2010, whose resection rate was total resection or subtotal resection, EBRT was completed and postoperative KPS was greater than or equal to 70, the MST with and without CK-SRT was 26.6 and 18.3 months, respectively (p = 0.1529). According to the Cox proportional hazards model, degree of resection, KPS, ACNU use, temozolomide use, bevacizumab use, EBRT dose, and CK-SRT use were good prognostic factors. Use of neuronavigation and use of intraoperative magnetic resonance imaging were related to higher resection rate, but not determined as prognostic factors. Conclusions. We observed a gradual improvement in glioblastoma outcome, presumably because of improvements in therapeutic modalities for surgery, anticancer agents, and radiation, but the efficacy of CK-SRT remains unclear.

Combination External Beam Radiotherapy and Intraluminal Brachytherapy for Non-radical Treatment of Oesophageal Carcinoma in Patients not Suitable for Surgery or Chemoradiation

AimsThis single-centre retrospective study evaluated combination external beam radiotherapy and high dose rate brachytherapy for patients in whom radical treatment was appropriate but comorbidity or frailty excluded this as an option. Materials and methodsIn total, 59 patients were selected for a combined approach and treated between October 2000 and October 2011; 68% were male. The median age was 77 years (range 53–88 years); 66% had adenocarcinoma, 31% squamous cell carcinoma. Tumour stage: I: 20%, II: 43%, III: 32% and IV: 3%. External beam radiotherapy doses of either 27 Gy/six fractions or 30 Gy/10 fractions were delivered, followed by high dose rate brachytherapy at doses of either 10 or 15 Gy utilising an iridium 192 source at 1 cm. ResultsThe median overall survival of all treated patients was 12.3 months; 1, 2 and 3 year survival rates were 51, 19 and 7%, respectively. Patients with stage I disease had a median survival of 16 months compared with 10 months for patients with stage III disease (P = 0.036). The pretreatment dysphagia score was associated with survival (P = 0.021). ConclusionsThis study shows the value of a purely radiation-based approach in a selected population. Treatment is deliverable with excellent compliance and the median survival compares favourably with unselected patients treated palliatively in our institution.

Predicting Radiation Therapy Outcome for Head and Neck Cancer Patients Using Artificial Neural Network (ANN)

Predicting Radiation Therapy Outcome for Head and Neck Cancer Patients Using Artificial Neural Network (ANN)

Impact of Race on Both Pathologic Extent of Disease and Administration of Adjuvant Radiation Therapy in a Cohort With Clinical Low-Risk Prostate Cancer Undergoing Radical Prostatectomy

Purpose/Objective(s): Androgen deprivation therapy (ADT) and standard dose external beam radiation therapy ( 70 Gy) have improved biochemical outcomes in intermediate risk (IR) prostate cancer. It is not known whether ADT improves outcomes in patients treated with brachytherapy. Our purpose is to evaluate the impact of ADT on biochemical failure free survival (bFFS) and overall survival (OS) in a multi-institutional database of IR prostate cancer patients treated with low dose rate prostate brachytherapy (LDR BT). Materials/Methods: From the Genitourinary Radiation Oncologists of Canada (GUROC) Prostate Cancer Risk Stratification (ProCaRS) database, a cohort of 859 patients with IR prostate cancer treated with LDR BTwith or without ADT was identified. Propensity scores were generated using multivariate regression based on age, baseline PSA, Gleason score and clinical stage. Patients treated with LDR alone were each matched to 2 patients who received the combination of LDR and ADT. Results: A 1:2 matching scenario (175 LDR BT : 350 LDR BT+ADT) provided the best balance of adjusted prognostic factors, a larger sample size than obtained with 1:1 matching, and standardized differences< 0.1 for prognostic factors used for matching. The 2 groups were balanced for age, baseline PSA, Gleason score and clinical stage. Median follow-up was longer in the LDR BT+ADT group (7.15 vs 4.21 years). After matching, there was no difference in bFFS (relative risk LDRBT+ADTZ 0.87, 95%CIZ 0.50-1.53); however, OS was worse in the group receiving ADT (relative risk LDR BT+ADT Z 2.83, 95%CIZ 1.00-7.98). Furthermore, a trend towardsworse cancer-related survival was observed for the LDR BT+ADT group (p Z 0.095). Conclusions: These results suggest that ADT does not benefit bFFS or OS in IR patients treated with LDR BT. Prospective studies are needed to investigate the role of ADT in IR prostate cancer patients treated with LDR BT. Author Disclosure: J. Rose: None. J.M. Crook: None. Y. Yang: None. A. Warner: None. J. Morris: None. T. Pickles: None. A. Martin: None. E. Vigneault: None. C. Catton: None. G. Rodrigues: None.

Androgen Deprivation Therapy in Intermediate-Risk Prostate Cancer Patients Treated With Low-Dose-Rate Brachytherapy: A Multi-institutional Propensity Score Matched Pair Analysis

Androgen deprivation therapy (ADT) and standard dose external beam radiation therapy (≤ 70 Gy) have improved biochemical outcomes in intermediate risk (IR) prostate cancer. It is not known whether ADT improves outcomes in patients treated with brachytherapy. Our purpose is to evaluate the impact of ADT on biochemical failure free survival (bFFS) and overall survival (OS) in a multi-institutional database of IR prostate cancer patients treated with low dose rate prostate brachytherapy (LDR BT).

Does Post–Neoadjuvant Therapy PET Response Predict Pathologic Outcomes in the Treatment of Sarcomas?

sarcomas (10), and other malignancies (2). 4 of these patients had radiation associated sarcomas within prior radiation field for different malignancies. Materials/Methods: The median age of the patients at diagnosis was 51 (range 7-75). The patients were treated from Feb, 2000 to Oct, 2013. 6 patients were treated with dural plaques during both stages of planned 2-stage operations. 46 patients were planned for treatment during one of the staged resection. The types of plaques used included Y-90, P-32 and Ir-192. Median dose was 10 Gy (range 7.5 e 17 Gy) prescribed to the dural surface in a single fraction. The median length of the dural plaque is 36mm, and the median arc of the dural plaque is 153 . All patients had also received preand/or postoperative photon/proton external beam radiation therapy. We limit spinal cord dose to 63/54 Gy RBE to surface/center. Results: In 7 of 51 patients, dural plaque brachytherapy was not given (4 because of intraoperative anatomic constraints, and 3 because of dural tears). Results are based on intention to treat analysis. The median follow up time from date of planned dural plaque brachytherapy is 17.7 months. Of the 3 patients treated for primary disease and had local recurrence, 2 presented with radiation associated sarcoma, which significantly limited their external beam radiation dose. No acute or late myelopathy could be attributed to dural plaque brachytherapy. 6 patients had intraoperative dural tear (none directly caused by plaque placement). In 3 of these 6 patients, dural plaque treatments were given. In 1 of the 3 patients, a persistent CSF leak developed postoperatively, and it eventually resolved without intervention. Conclusions: Dural plaque brachytherapy allows high dose of radiation to be safely delivered to the dural surface. Dural plaque shall be considered in situation when tumors are in close proximity to spinal cord, and sufficient dose of radiation cannot be delivered with external beam radiation therapy alone. Author Disclosure: D.D. Yip: None. T.F. DeLaney: None. A. Jacobson: None. F.J. Hornicek: None. J.H. Schwab: None. T.C. Mauceri: None. Y. Chen: None.

Dose to the Bladder Neck Is a Strong Predictor for Acute Toxicity After Combined LDR Brachytherapy and External Beam Radiation Therapy for Prostate Cancer: Implications for New Dose Constraints

To identify an anatomic structure correlated with acute urinary toxicity (AUT) in patients with prostate cancer treated with a combination of low dose rate (LDR) brachytherapy and external beam radiation therapy (EBRT).

Analysis of the Cancer of the Prostate Risk Assessment to Predict for Biochemical Failure After External Beam Radiotherapy or Prostate Seed Brachytherapy

To analyze the value of the Cancer of the Prostate Risk Assessment (CAPRA) score to predict biochemical failure (bF) in patients with D'Amico low- or intermediate-risk prostate cancer treated with different radiation techniques. We analyzed 744 patients treated with either external beam radiotherapy (52.7%) or permanent-seed prostate brachytherapy (47.3%) without any androgen deprivation. External beam radiotherapy dose levels were extreme hypofractionation (45 Gy in 9 fractions) in 10%, 76-79.2 Gy (in 1.8-2.0 Gy per fraction) in 32.7%, and 70.2-74 Gy in 10%. All patients had a minimum of 36-month follow-up. Cox regression analysis was used for univariate and multivariate analysis to predict for bF, as per the Phoenix definition (prostate-specific antigen-nadir + 2 ng/mL). Median follow-up for patients without bF was 56 months (range, 36-114 months). In univariate analysis, CAPRA score as a continuous variable was predictive of bF (hazard ratio [HR], 1.49; 95% confidence interval [CI], 1.23-1.79; P <.001), and in multivariate analysis adjusted for treatment type, the HR was 1.39 (95% CI, 1.14-1.71; P = .002). D'Amico intermediate-risk vs low-risk patients had an HR for bF of 1.93 (95% CI, 1.07-3.47; P = .029) in univariate analysis, but the difference was not statistically significant anymore after adjustment for treatment type, (P = .206). The area under the curve of the CAPRA score as a continuous variable at 3 and 5 years was 0.66 and 0.62, respectively (P = .005 for both years). The CAPRA score is predictive of bF. Each 1-point rise increased the risk of bF by 39%, which is comparable to surgical series.

Anticipated Intraoperative Electron Beam Boost, External Beam Radiation Therapy, and Limb-Sparing Surgical Resection for Patients with Pediatric Soft-Tissue Sarcomas of the Extremity: A Multicentric Pooled Analysis of Long-Term Outcomes

To perform a joint analysis of data from 3 contributing centers within the intraoperative electron-beam radiation therapy (IOERT)-Spanish program, to determine the potential of IOERT as an anticipated boost before external beam radiation therapy in the multidisciplinary treatment of pediatric extremity soft-tissue sarcomas. From June 1993 to May 2013, 62 patients (aged <21 years) with a histologic diagnosis of primary extremity soft-tissue sarcoma with absence of distant metastases, undergoing limb-sparing grossly resected surgery, external beam radiation therapy (median dose 40 Gy) and IOERT (median dose 10 Gy) were considered eligible for this analysis. After a median follow-up of 66 months (range, 4-235 months), 10-year local control, disease-free survival, and overall survival was 85%, 76%, and 81%, respectively. In multivariate analysis after adjustment for other covariates, tumor size >5 cm (P=.04) and R1 margin status (P=.04) remained significantly associated with local relapse. In regard to overall survival only margin status (P=.04) retained association on multivariate analysis. Ten patients (16%) reported severe chronic toxicity events (all grade 3). An anticipated IOERT boost allowed for external beam radiation therapy dose reduction, with high local control and acceptably low toxicity rates. The combined radiosurgical approach needs to be tested in a prospective trial to confirm these results.

External beam radiotherapy plus single-fraction high dose rate brachytherapy in the treatment of locally advanced prostate cancer

PurposeTo evaluate the efficacy and toxicity of external beam radiation therapy (EBRT) plus high-dose-rate brachytherapy (HDRB) as a boost in patients (pts) with intermediate or high-risk prostate cancer. Methods and materialsFrom 2002 to July 2012, 377pts with a diagnosis of intermediate or high-risk prostate cancer were treated with EBRT plus HDRB. Median patient age was 66years (range, 41–86). Most patients (347pts; 92%) were classified as high-risk (stage T2c–T3, or PSA>20ng/mL, or GS⩾8), with 30 patients (8%) considered intermediate risk. All patients underwent EBRT at a prescribed dose of 60.0Gy (range, 45–70Gy) to the prostate and seminal vesicles. A total of 120pts (31%) received a dose of 46Gy (45–50Gy) to the true pelvis. All pts received a single-fraction 9Gy (9–15Gy) HDR boost. Most patients (353; 94%) were prescribed complete androgen deprivation therapy (ADT). Overall survival (OS), cause-specific survival (CSS), and biochemical relapse-free survival (BRFS) rates were calculated. In the case of BRFS, patients with <26months of follow-up (n=106) were excluded to minimize the impact of ADT. ResultsThe median follow-up for the entire sample was 50months (range, 12–126), with 5-year actuarial OS and CSS, respectively, of 88% (95% confidence interval [CI]: 84–92) and 98% (95% CI: 97–99). The 5-year BRFS was 91% (95% CI: 87–95) in the 271pts with ⩾26months (median, 60months) of follow-up. Late toxicity included grade 2 and 3 gastrointestinal toxicity in 17 (4.6%) and 6pts (1.6%), respectively, as well as grades 2 and 3 genitourinary toxicity in 46 (12.2%) and 3pts (0.8%), respectively. ConclusionThese long-term outcomes confirm that EBRT plus a single-fraction HDRB boost provides good results in treatment-related toxicity and biochemical control. In addition to the excellent clinical results, this fractionation schedule reduces physician workload, treatment-related expenses, patient discomfort and risks associated with anaesthesia. We believe these findings support the use of single-fractionation boost techniques.

SU-E-T-206: Improving Radiotherapy Toxicity Based On Artificial Neural Network (ANN) for Head and Neck Cancer Patients

Purpose/Objective(s): The aim of this study is to build the estimator of toxicity using artificial neural network (ANN) for head and neck cancer patients Materials/Methods: An ANN can combine variables into a predictive model during training and considered all possible correlations of variables. We constructed an ANN based on the data from 73 patients with advanced H and N cancer treated with external beam radiotherapy and/or chemotherapy at our institution. For the toxicity estimator we defined input data including age, sex, site, stage, pathology, status of chemo, technique of external beam radiation therapy (EBRT), length of treatment, dose of EBRT, status of post operation, length of follow-up, the status of local recurrences and distant metastasis. These data were digitized based on the significance and fed to the ANN as input nodes. We used 20 hidden nodes (for the 13 input nodes) to take care of the correlations of input nodes. For training ANN, we divided data into three subsets such as training set, validation set and test set. Finally, we built the estimator for the toxicity from ANN output. Results: We used 13 input variables including the status of local recurrences and distant metastasis and 20 hidden nodes for correlations.more » 59 patients for training set, 7 patients for validation set and 7 patients for test set and fed the inputs to Matlab neural network fitting tool. We trained the data within 15% of errors of outcome. In the end we have the toxicity estimation with 74% of accuracy. Conclusion: We proved in principle that ANN can be a very useful tool for predicting the RT outcomes for high risk H and N patients. Currently we are improving the results using cross validation.« less

Biological Effects of 125I Seeds Radiation on A549 Lung Cancer Cells: G2/M Arrest and Enhanced Cell Death

External beam radiation (EBRT) and 125I seeds continuous low dose rate radiation (CLDR) were used to treat patients with lung cancer. We herein investigated the biological effects of EBRT and CLDR on lung cancer cells. A549 human lung cancer cell line was thus exposed to different doses of EBRT and CLDR. CLDR was more efficient to inhibit cell growth than EBRT. CLDR induced increased DNA damage as evidenced by long-lasting p-H2AX activity. The enhanced inhibitory effects of CLDR on lung cancer cell growth may be, at least in part, due to the increased Bax/Bcl2 ratio and cyclin B1-mediated G2/M arrest.

Radiation-Induced Modulation of Costimulatory and Coinhibitory T-Cell Signaling Molecules on Human Prostate Carcinoma Cells Promotes Productive Antitumor Immune Interactions

We sought to determine if single-dose external beam radiation therapy (EBRT) could modulate the expression signature of T-cell costimulatory and coinhibitory molecules in human prostate cancer (PCa) cell lines in vitro. We investigated the functional impact of irradiated PCa cells with a modulated costimulatory profile on responder T-cell activity. We used three PCa cell lines (DU145, PC3, and LNCaP) and two epithelial cell lines from noncancerous prostate and lung tissue. After 72 hours of EBRT, surface expression of four immunostimulatory molecules (CD70, CD275/ICOSL, CD134L/OX40L, and CD137L/41BBL) and two immunosuppressive markers (CTLA-4/CD152 and PD-L1/CD274) were evaluated by flow cytometry. We evaluated the impact of several radiation doses and the longevity of modulated expression. We examined the functional impact of radiation-induced modulation of cancer cells by cytotoxic T cells (CTL) cytotoxicity and ELISPOT assay for interferon-gamma (IFN-γ) production. Last, we evaluated whether IFN-γ-induced PD-L1 expression could be reversed by EBRT. After 10 Gy EBRT, expression of OX40L and 41BBL increased in all three PCa cell lines; expression of CD70 and ICOSL increased in PC3 cells. Conversely, a decrease in PD-L1 expression in DU145 and PC3 cells was detectable up to 144 hours after EBRT. No PD-L1 was detected in LNCaP. Epithelial cells from normal prostate were not modulated by radiation. CTL cytolytic activity and IFN-γ production were enhanced by interaction with irradiated PCa cells. Finally, EBRT failed to prevent IFN-γ-induced upregulation of PD-L1. We demonstrate that a single dose of EBRT increased surface expression of costimulatory molecules and decreased the expression of coinhibitory molecules in human PCa cell lines. Changes in irradiated tumor cells led to functional enhancement of T-cell activity, despite EBRT failing to reduce IFN-γ-induced expression of PD-L1. These data suggest that combining radiotherapy with T-cell stimulating immunotherapy may be an attractive strategy for cancer treatment.

Quantitative monitoring of radiation induced skin toxicities in nude mice using optical biomarkers measured from diffuse optical reflectance spectroscopy.

Monitoring the onset of erythema following external beam radiation therapy has the potential to offer a means of managing skin toxicities via biological targeted agents - prior to full progression. However, current skin toxicity scoring systems are subjective and provide at best a qualitative evaluation. Here, we investigate the potential of diffuse optical spectroscopy (DOS) to provide quantitative metrics for scoring skin toxicity. A DOS fiberoptic reflectance probe was used to collect white light spectra at two probing depths using two short fixed source-collector pairs with optical probing depths sensitive to the skin surface. The acquired spectra were fit to a diffusion theory model of light transport in tissue to extract optical biomarkers (hemoglobin concentration, oxygen saturation, scattering power and slope) from superficial skin layers of nude mice, which were subjected to erythema inducing doses of ionizing radiation. A statistically significant increase in oxygenated hemoglobin (p < 0.0016) was found in the skin post-irradiation - confirming previous reports. More interesting, we observed for the first time that the spectral scattering parameters, A (p = 0.026) and k (p = 0.011), were an indicator of erythema at day 6 and could potentially serve as an early detection optical biomarker of skin toxicity. Our data suggests that reflectance DOS may be employed to provide quantitative assessment of skin toxicities following curative doses of external beam radiation.

The Cancer of the Prostate Risk Assessment (CAPRA) score predicts biochemical recurrence in intermediate-risk prostate cancer treated with external beam radiotherapy (EBRT) dose escalation or low-dose rate (LDR) brachytherapy

To study the prognostic value of the University of California, San Francisco Cancer of the Prostate Risk Assessment (CAPRA) score to predict biochemical failure (bF) after various doses of external beam radiotherapy (EBRT) and/or permanent seed low-dose rate (LDR) prostate brachytherapy (PB). We retrospectively analysed 345 patients with intermediate-risk prostate cancer, with PSA levels of 10-20 ng/mL and/or Gleason 7 including 244 EBRT patients (70.2-79.2 Gy) and 101 patients treated with LDR PB. The minimum follow-up was 3 years. No patient received primary androgen-deprivation therapy. bF was defined according to the Phoenix definition. Cox regression analysis was used to estimate the differences between CAPRA groups. The overall bF rate was 13% (45/345). The CAPRA score, as a continuous variable, was statistically significant in multivariate analysis for predicting bF (hazard ratio [HR] 1.37, 95% confidence interval [CI] 1.10-1.72, P = 0.006). There was a trend for a lower bF rate in patients treated with LDR PB when compared with those treated by EBRT ≤ 74 Gy (HR 0.234, 95% CI 0.05-1.03, P = 0.055) in multivariate analysis. In the subgroup of patients with a CAPRA score of 3-5, CAPRA remained predictive of bF as a continuous variable (HR 1.51, 95% CI 1.01-2.27, P = 0.047) in multivariate analysis. The CAPRA score is useful for predicting biochemical recurrence in patients treated for intermediate-risk prostate cancer with EBRT or LDR PB. It could help in treatment decisions.

CT-based interstitial brachytherapy in advanced gynecologic malignancies: Outcomes from a single institution experience

To evaluate the clinical outcomes of women receiving a "short" course of high-dose-rate gynecologic interstitial brachytherapy (HDR-ISBT) boost with CT-based 3D planning. Forty-seven women with no prior radiation received HDR-ISBT from August 2004 to February 2012. The mean external beam radiotherapy dose was 45Gy. A mean HDR-ISBT boost dose of 18.4Gy was delivered over 2-4 fractions. Dose volume histograms (DVHs) were computed for organs at risk and clinical target volume. With a median followup of 34.8 months, the 3-year local control rate was 68%. Sixteen patients were identified to have tumor recurrence (including eight local). The median time to any recurrence was 26.8 months. Relapse-free survival and overall survival at 3 years was 65% and 73%, respectively. Ten patients experienced Grade 3 late toxicity, mainly vaginal (5) and proctitis (3). The mean prescription volume (V100) was 85cc and the mean D90 to CTV was 98%. The mean cumulative dose to tumor was 69.9Gy (equivalent dose in 2Gy). The mean cumulative equivalent dose in 2Gy to D2cc of bladder and rectum was 60.9Gy and 63.0Gy, respectively. A "short" course HDR-ISBT is effective, safe, and convenient with acceptable local control and toxicity. Higher dose per fraction is similar to an external beam radiotherapy stereotactic boost with the inherent advantages of brachytherapy. A shorter overall time for HDR-ISBT means less time that patients are immobilized and in hospital, making it less resource intensive than a longer course.