HDR BT Research Articles

PV-0034: HDR BT alone in endometrial cancer: up-date of Piedmont experience in 18 years (71 patients)

PV-0034: HDR BT alone in endometrial cancer: up-date of Piedmont experience in 18 years (71 patients)

EP-2015: Acute toxicity in HDR BT of skin cancer with very high viscosity addition silicone custom made molds

EP-2015: Acute toxicity in HDR BT of skin cancer with very high viscosity addition silicone custom made molds

Planning CT Scans for the Treatment of HDR Vaginal Vault Brachytherapy: An Evaluation of Its Role to Determine the Dose to the Organs at Risk

To assess the role of CT-based treatment planning for high dose rate brachytherapy (HDR BT) to the vaginal vault by determining the frequency with which imaging changes the course of treatment and by comparing the dose given the organs at risk (OAR, rectum, bladder, and bowels) to accepted doses used for cervical cancer treatments. All patients who received HDR BT to the vaginal vault for endometrial or cervical cancer from January 2011 to January 2014 were included. Standard prescriptions were 5.5 Gy × 4 or 7.0 Gy × 3 (HDR BT alone) or 5.5 Gy × 2 at 5mm depth (HDR BT following 45 Gy/25/5 weeks pelvic irradiation). Each patient had a CT scan with the applicator in place at the time of the first fraction. The OAR were contoured and a standard plan was applied and reviewed. For this study all OAR contours were reviewed and adjusted by a single radiation oncologist (FB) for consistency. The minimum dose to the maximally irradiated 2cc (D2cc) for each OAR was determined from the reviewed contours. It was assumed the same dose was delivered at each fraction. These were then converted to EQD2 doses assuming α/β=3 and, as applicable, summed with the EQD2 dose from the external beam component. All doses reported are EQD2 doses. All charts were reviewed to track whether or not changes were made to the course of treatment based on the CT images. 82 patients were included in this study of whom 78 (95%) received the intended prescription. Of the remaining 4 patients, 3 refused a second fraction and 1 had the number of fractions reduced due to the OAR dose. The D2cc OAR tolerances used were 90 Gy (bladder), 75 Gy (rectum and sigmoid), and 55 Gy (small bowel). None of the patients who received the intended dose approached cervival cancer tolerance limits for D2cc doses for the bladder, rectum, or sigmoid. For these 78 patients the mean D2cc for the bladder, rectum, sigmoid, and small bowels were 48.6±13.1Gy, 45.2±13.8Gy, 35.1±18.0Gy, and 33.3±20.5Gy, respectively. 3 patients exceeded the small bowel limit by 0.4-2.7Gy. For the patient whose dose was adjusted due to concerns for OAR toxicity, the dose was recalculated as if the entire dose was delivered. This resulted OAR doses less than the cervical cancer tolerance limits for all except the small bowel which would have received 59.9 Gy. No patient who received the intended brachytherapy dose approached the bladder, rectum, or sigmoid tolerance levels as recommended by GEC-ESTRO for image guided cervical brachytherapy. Although there were 3 cases where the small bowel limit was exceeded, the dose limit is subject of ongoing research, and has not been linked to specific outcome. Only 1 patient (1.2%) had their course of treatment altered based on the treatment planning CT scan and that patient would only have marginally exceeded the small bowel limit if treatment had proceeded as intended. Further research on tolerance doses to the OAR in the settings of adjuvant treatment will be helpful to clarify the role of CT-planning for endocavitary HDR BT.

Combined HDR brachytherapy boost plus external beam radiotherapy by IMRT versus external beam radiotherapy alone IMRT in intermediate- and high-risk prostate cancer: Dosimetric analysis from a randomized control trial.

134 Background: Dose escalation by IMRT or brachytherapy significantly improves biochemical control in localized prostate cancer. In this prospective randomized study we compared dose conformity between two modalities HDR brachytherapy and IMRT to deliver a boost to the prostate after External beam Radiotherapy (EBRT). Methods: 20 patients with localized prostate cancer were randomized to receive IMRT alone or IMRT plus brachytherapy. After randomization, all patients received EBRT 45Gy/25#/5 weeks by IMRT in phase I. In phase II patients received either HDR brachytherapy 19Gy/2# (Arm A) or EBRT 29Gy/15#/3weeks (Arm B) and EQD2–DVH parameters were calculated for comparison. EQD2 was calculated with α/β ratio of 1.5Gy and 3Gy for prostate & 3Gy for rectum and bladder. Results: The median age, stage distribution, Gleason score, PSA and prostate volume of the cohort were 69.5 years, T2b–T3b, 7, 38.5ng/ml and 47.4cc respectively.The HDR BT delivered higher mean doses to PTV. In phase II, HDR BT vs IMRT the mean EQD2 for 95% of prostate volume, 33% of rectal volume was 45.7Gy vs 28.4Gy, 6.8Gy vs 17.4 Gy respectively; Dmean of rectum and bladder was 7.4 Gy vs 13.5Gy and 5.4Gy vs 12.7Gy respectively. Conclusions: HDR BT produced more conformal plan and lower OAR doses than IMRT. Dose escalation for prostate tumors by HDR BT may be preferred as easily achievable. [Table: see text]

High-Dose-Rate Brachytherapy Boost Effect on Local Tumor Control in Young Women With Breast Cancer

To evaluate the local control rate and complications of a single fraction of high-dose-rate brachytherapy (HDR BT) boost in women aged 45 yeas and younger after breast-conserving therapy. Between 1999 and 2007, 167 patients between the ages of 26 and 45 years old (72 were 40 years old or younger), with stages T1 to T2 invasive breast cancer with disease-free margin status of at least 5 mm after breast-conserving surgery received 46 to 50 Gy whole-breast irradiation plus a 7-Gy HDR-BT boost ("fast boost"). An axillary dissection was performed in 72.5% of the patients and sentinel lymph node biopsy in 27.5%. A supraclavicular area was irradiated in 19% of the patients. Chemotherapy was used in 86% of the patients and hormone treatment in 77%. Clinical nodes were present in 18% and pathological nodes in 29%. The pathological stage was pT0: 5%, pTis: 3%, pT1: 69% and pT2: 23%. Intraductal component was present in 40% and 28% were G3. At a median follow-up of 92 months, 9 patients relapsed on the margin of the implant, and 1 patient in another quadrant, resulting in a 10-year local relapse rate of 4.3% and a breast relapse rate of 4.9%, with breast preservation in 93.4%; no case of mastectomy due to poor cosmesis arose. Actuarial 5- and 10-year disease-free, cause-specific, and overall survival rates were 87.9% and 85.8%, and 92.1% and 88.4%, and 92.1% and 87.3%, respectively. In a univariate analysis, triple-negative cases and negative hormone receptors did worse, but in a multivariate analysis, only the last factor was significant for local and breast control. Asymptomatic fibrosis G2 was recorded in 3 cases, and there were no other late complications. Cosmetic results were good to excellent in 97% of cases. A single dose of 7 Gy using the fast-boost technique is well tolerated, with a low rate of late complications and improved local tumor control in women aged 45 and younger, compared to published data. This approach is recommended in breast-preserving treatment.

A method to estimate composite doses for organs at risk in prostate cancer patients treated with EBRT in combination with HDR BT

Background. When evaluating late toxicity after combined external beam radiation therapy (EBRT) and high-dose rate brachytherapy (HDR BT) prostate cancer treatments, it is important that the composite dose distribution is taken into account. This can be challenging if organ-at-risk (OAR) dose data are incomplete, i.e. due to a limited ultrasound imaging field-of-view in the HDR BT procedure. This work proposes a method that provides estimates of composite OAR doses for such situations.Material and methods. Original EBRT, simulated HDR BT, and composite dose-volume histograms (DVHs) for 10 pelvic OARs in 30 prostate cancer cases were used for method implementation and evaluation (EBRT: 25 × 2.0 Gy + BT: 2 × 10.0 Gy). The proposed method used information from the EBRT DVH to estimate OAR BT doses (with or without fractionation correction). Coefficients of determination (R2) were calculated for linear relationships between several EBRT DVH parameters and a BT DVH parameter of interest. The largest R2 value decided the relationship that best predicted the BT DVH parameter. The composite dose value was then calculated by adding the EBRT DVH and the estimated BT DVH parameter values and was compared to the reference composite value (in 1200 OAR/patient/parameter cases).Results. The linear relationships had an average R2 of 0.68 (range 0.42–0.88). Only one ninth of the 1200 estimated composite DVH values differed more than 2 Gy from their reference values.Conclusion. Given a successful implementation, the proposed method only requires original or simulated BT plan data for a subset of patients to estimate composite doses for large study populations in a time-efficient manner. This can assist in evaluating radiation-induced late toxicity in multimodality treatments with limited OAR dose data.

HDR brachytherapy combined with interstitial hyperthermia in locally advanced cervical cancer patients initially treated with concomitant radiochemotherapy – a phase III study

Background and purposeThe aim of this randomised trial was to investigate whether hyperthermia (HT) combined with interstitial brachytherapy (ISBT) has any influence on local control (LC), disease-free survival (DFS), or acute and late side effects in patients with advanced cervical cancer. Materials and methodsAfter radiochemotherapy, consecutive patients with cervical cancer (FIGO stage II–III) were randomly assigned to two treatment groups, either ISBT alone or ISBT combined with interstitial hyperthermia (ISHT). A total of 205 patients were included in the statistical analysis. Once a week, HT, at a temperature above 42.5°C, was administered for 45min before and during the HDR BT. ResultsThe median follow-up time was 45months (range 3–72months). An effect of hyperthermia was not detected for disease-free survival (DFS) (log-rank test: p=0.178) or for local control (LC) (p=0.991). According to Cox’s analysis, HT did not significantly influence failure or interactions with potential prognostic factors for LC or DFS. Statistical differences were not observed for the distribution of early and late complications between the HT and non HT groups. ConclusionsISHT is well-tolerated and does not affect treatment-related early or late complications. Improvements in DFS and LC were not observed following the addition of ISHT to ISBT.

Stereotactic body radiotherapy for localized prostate cancer: disease control and quality of life at 6 years

BackgroundStereotactic body radiotherapy (SBRT) may yield disease control for prostate cancer in a brief, hypofractionated treatment regimen without increasing treatment toxicity. Our report presents a 6-year update from 304 low- (n = 211), intermediate- (n = 81), and high-risk (n = 12) prostate cancer patients who received CyberKnife SBRT.MethodsThe median PSA at presentation was 5.8 ng/ml. Fifty-seven patients received neoadjuvant hormonal therapy for up to one year. The first 50 patients received a total dose of 35 Gy in 5 fractions of 7 Gy. The subsequent 254 patients received a total dose of 36.25 Gy in 5 fractions of 7.25 Gy. Toxicity was assessed with the Expanded Prostate Cancer Index Composite questionnaire and the Radiation Therapy Oncology Group urinary and rectal toxicity scale. Biochemical failure was assessed using the nadir + 2 definition.ResultsNo patients experienced Grade III or IV acute complications. Fewer than 5% of patients experienced any acute Grade II urinary or rectal toxicities. Late urinary Grade II complications were observed in 4% of patients treated to 35 Gy and 9% of patients treated to 36.25 Gy. Five (2%) late Grade III urinary toxicities occurred in patients who were treated with 36.25 Gy. Late Grade II rectal complications were observed in 2% of patients treated to 35 Gy and 5% of patients treated to 36.25 Gy. Bowel and urinary quality of life (QOL) scores initially decreased, but later returned to baseline values. An overall decrease of 20% in the sexual QOL score was observed. QOL in each domain was not differentially affected by dose. For patients that were potent prior to treatment, 75% stated that they remained sexually potent. Actuarial 5-year biochemical recurrence-free survival was 97% for low-risk, 90.7% for intermediate-risk, and 74.1% for high-risk patients. PSA fell to a median of 0.12 ng/ml at 5 years; dose did not influence median PSA levels.ConclusionsIn this large series with long-term follow-up, we found excellent biochemical control rates and low and acceptable toxicity, outcomes consistent with those reported for from high dose rate brachytherapy (HDR BT). Provided that measures are taken to account for prostate motion, SBRT’s distinct advantages over HDR BT include its noninvasiveness and delivery to patients without anesthesia or hospitalization.

Adaptive image guided brachytherapy for cervical cancer: A combined MRI-/CT-planning technique with MRI only at first fraction

PurposeTo investigate and test the feasibility of adaptive 3D image based BT planning for cervix cancer patients in settings with limited access to MRI, using a combination of MRI for the first BT fraction and planning of subsequent fractions on CT. Material and methodsFor 20 patients treated with EBRT and HDR BT with tandem/ring applicators two sets of treatment plans were compared. Scenario one is based on the “gold standard” with individual MRI-based treatment plans (applicator reconstruction, target contouring and dose optimization) for two BT applications with two fractions each. Scenario two is based on one initial MRI acquisition with an applicator in place for the planning of the two fractions of the first BT application and reuse of the target contour delineated on MRI for subsequent planning of the second application on CT. Transfer of the target from MRI of the first application to the CT of the second one was accomplished by use of an automatic applicator-based image registration procedure. Individual dose optimization of the second BT application was based on the transferred MRI target volume and OAR structures delineated on CT.DVH parameters were calculated for transferred target structures (virtual dose from MRI/CT plan) and CT-based OAR.The quality of the MRI/CT combination method was investigated by evaluating the CT-based dose distributions on MRI-based target and OAR contours of the same application (real dose from MRI/CT plan). ResultsThe mean difference between the MRI based target volumes (HR CTVMRI2) and the structures transferred from MRI to CT (HR CTVCT2) was −1.7±6.6cm3 (−2.9±20.4%) with a median of −0.7cm3.The mean difference between the virtual and the real total D90, based on the MRI/CT combination technique was −1.5±4.3Gy EQD2. This indicates a small systematic underestimation of the real D90. ConclusionsA combination of MRI for first fraction and subsequent CT based planning is feasible and easy when automatic applicator-based image registration and target transfer are technically available. The results show striking similarity to fully MRI-based planning in cases of small tumours and intracavitary applications, both in terms of HR CTV coverage and respecting of OAR dose limits. For larger tumours and complex applications, as well as situations with unfavourable OAR topography, especially for the sigmoid, MRI based adaptive BT planning remains the superior method.

72P Cosmetic Results of High Dose Rate Brachytherapy Boost Versus Electron Beam Boost in the Treatment of Early Breast Cancer

ObjectiveTo evaluate the effect of high dose rate brachytherapy (HDR BT) boost versus electron beam boost on local tumor control, side effects and cosmesis after breast conserving surgery (BCS) in early breast cancer. Methods40 women with stage I-II breast cancer who underwent BCS were treated by 50 Gy adjuvant radiotherapy to the whole breast and then randomly assigned to receive 15-16 Gy boost to the primary tumor bed either with HDR BT or electron beam using linear accelerator. Breast cancer related events and cosmetic results were assessed over one and a half year. ResultsThere was no significant difference in local tumor control between patients treated with electron or HDR BT boost over a period of one and a half year. Patients in the electron group had better cosmesis, and decreased fibrosis and pigmentation than those in the implant group. ConclusionsPatients with early breast cancer after undergoing BCS and whole breast irradiation have better cosmetic results and reduced chances of fibrosis when they are given electron boost as compared to HDR BT boost. DisclosureAll authors have declared no conflicts of interest.

Complete pathologic remission after preoperative high-dose brachytherapy in patients with operable cervical cancer: preliminary results of a prospective randomized study

The purpose of the study was a preliminary evaluation of the efficacy of preoperative intracavitary high-dose-rate brachytherapy (HDR BT) in sterilization of the specimen of operable cervical cancer patients enrolled into a prospective, randomized study. Between 2005 and 2010, 100 operable cervical cancer patients of FIGO stage I/A2 (n=4), I/B1 (n=51), I/B2 (n=19), IIA (n=17), and proximal II/B (n=9) were randomized in two arms: in arm "A" (n=50) allocated treatment was 2x8 Gy preoperative intracavitary HDR BT followed by radical surgery, in arm "B" (n= 50) no preoperative treatment was given before the planned radical Wertheim hysterectomy. The rates of pathologic complete remission (pCR) were compared using the Fisher-exact test. In arm "A" 41 patients (82%), in arm "B" 42 patients (84%) underwent radical hysterectomy. The rate of pCR after preoperative BT was 26.8% (11/41), while in the control group the specimen was free of tumor in 7.1% (3/42; p=0.0204). Preoperative HDR BT for cervical cancer patients significantly increases the rate of pathologically tumor-free specimens. Longer follow-up is needed to evaluate the impact of pCR on local tumor control and survival. Our preliminary results support further enrollment of patients into our randomized clinical trial.

Dosimetric Comparison of High-Dose-Rate Brachytherapy and Intensity-Modulated Radiation Therapy as a Boost to the Prostate

We compared the dose conformity of two radiation modalities: high-dose-rate brachytherapy (HDR BT) and intensity-modulated radiation therapy (IMRT) to deliver a boost to the prostate after external beam radiotherapy (EBRT). Ten successive patients with prostate adenocarcinoma treated with a single 10-Gy HDR BT boost after EBRT were investigated. Four theoretical IMRT plans were computed: (a) 32.85 Gy IMRT and (b) 26 Gy IMRT with CTV-PTV expansions, doses corresponding to the equivalent dose in 2-Gy fractions (EQD2) of one 10-Gy fraction calculated with a prostate alpha/beta ratio of respectively 1.5 and 3 Gy; and (c) 32.85 Gy IMRT and (d) 26 Gy IMRT without CTV-PTV expansions. The dose-volume histogram values converted in EQD2 with an alpha/beta ratio of 3 Gy for the organs at risk were compared. The HDR BT plan delivered higher mean doses to the PTV compared with IMRT plans. In all, 33% of the rectal volume received a mean dose of 5.32 +/- 0.65 Gy and 20% of bladder volume received 4.61 +/- 1.24 Gy with HDR BT. In comparison, doses delivered with IMRT were respectively 13.4 +/- 1.49 Gy and 10.81 +/- 4 Gy, even if only 26 Gy was prescribed to the PTV with no CTV-PTV expansion (p < 0.0001). The hot spots inside the urethra were greater with HDR BT but acceptable. Use of HDR BT produced a more conformal plan for the boost to the prostate than IMRT even without CTV-PTV expansions.

Perioperative Hyperfractionated High-Dose Rate Brachytherapy for the Treatment of Soft Tissue Sarcomas: Multicentric Experience

Low-dose rate brachytherapy is a well-established adjuvant treatment for soft tissue sarcomas (STS). The experience with high-dose rate brachytherapy (HDR BT) in this indication is limited. The purpose of our study was to evaluate the viability of perioperative hyperfractionated HDR BT for STS. Forty-five patients with primary (17 cases) or recurrent (28 cases) STS were treated with resection and HDR BT between 1998 and 2007. Eleven patients were treated with HDR BT alone (mean dose 40 Gy; 30-54 Gy) and 34 were treated with a combination of HDR BT (mean dose 24 Gy; 15-30 Gy) and external beam radiotherapy (EBRT) (40-50 Gy). Hyperfractionation, 3 Gy twice daily, was used for HDR BT with plastic tubes. Adjuvant chemotherapy was indicated for patients with high risk of dissemination. Local control (LC) was achieved in 17 patients (100%) treated for primary tumor and in 18 of 28 patients (64%) treated for recurrence; this difference was statistically significant (p = 0.004). Distant metastases occurred in seven patients (15.6%). The 5-year overall survival was 70%; the 5-year local control was 74%. LC was significantly better for extremities sarcomas in comparison with trunk tumors, for patients treated with EBRT and BT in comparison with BT alone, and for doses >65 Gy. Our study suggests that perioperative HDR BT is a promising method for achieving high biological doses with good LC in the postoperative radiotherapy of STS and that combination of BT and EBRT provides better tumor control than BT alone.

On the radiobiologic implications for intracavitary HDR brachytherapy of cervical carcinoma based on 3D CT imaging and Gynecological GEC-ESTRO recommendations

Purpose: Quantify radiobiologic implications—that have been limited for 2D image-based high-dose-rate brachytherapy (HDR BT) plans, employing 3D CT imaging and the gynecological GEC-ESTRO recommendations.

Exclusive high dose rate brachytherapy (HDR-BT) for early stage non-small cell lung carcinoma: Results of a retrospective study in 226 patients

7688 Objective: To evaluate efficacy and toxicity of HDR BT in non operable endobronchial carcinoma from a retrospective multicentric study. Patients and Methods: Criteria for selection: non small cell carcinoma accessible to fiberoptic bronchoscopy, no extrabronchial extension on CT, contraindication to surgery and external radiation therapy (ERT). Statistical analysis: survival curves calculated with the Kaplan-Meier method and compared with the Logrank test; Cox model to evaluate in uni and multivariate analysis the impact on survival and complications of these parameters: location of tumor: lobar or segmental vs main stem bronchus, previous ERT vs no, total dose:= 30 Gy vs less, dose per fraction:= 5 Gy vs more, number of catheter(s):1 vs = 2. Results: Between 1991 and 2006, 226 patients from 9 radiotherapy departments were included. Main characteristics of tumors: squamous-cell histology: 96%, stage Tis: 60, T1: 153, T2: 9, Tx 4; lobar or segmental location: 91%. 51 patients (22.5%) had received ERT for previous lung cancer(s). Characteristics of HDR BT were: total dose = 30 Gy: 70%, dose per fraction = 5 Gy: 66%, 1 catheter: 46%. Dose was prescribed at 1 cm from the radius. Mean follow-up was 30.4 months (9- 116). Histologic evaluation was performed at 3 months in 137 patients. 92% had a complete response. 128 patients were died: intercurrent disease 45, local failure 35, complications 13. Two and 5-year survival: overall: 57%, 29%; specific (death of lung cancer) 81%, 56%; local- relapse free (LRF) 68%, 50%. Toxicity included 1.3% pneumothorax, hemoptysis 6.6% (5% fatal), bronchitis 20%. In univariate analysis: overall, specific and LRF survival were better for lobar or segmental location vs main stem bronchus (p=0.0001), overall and specific survival were higher with no previous ERT (p=0.006). In multivariate analysis, lobar or segmental location was associated with improved overall (p=0.0001) and LRF (p=0.003) survival. LRF survival was better in patients treated with = 2 catheters (p=0.007). No factor influence frequency of complications. Conclusion: This large retrospective study confirmed that HDRBT is efficient and safe in medically inoperable patients particulary with lobar or segmental endobronchial carcinoma. No significant financial relationships to disclose.

P92 Accelerated partial breast irradiation (APBI) using interstitial high dose rate brachytherapy (HDR BT): early toxicity and technical aspects

P92 Accelerated partial breast irradiation (APBI) using interstitial high dose rate brachytherapy (HDR BT): early toxicity and technical aspects

67 Intraarterial 192Ir HDR BT for prophylaxis of restenosis after femoropopliteal transluminal angioplasty; prospective; randomized trial-Vienna 2; results after 6 months minimum follow-up; risk factor analysis

67 Intraarterial 192Ir HDR BT for prophylaxis of restenosis after femoropopliteal transluminal angioplasty; prospective; randomized trial-Vienna 2; results after 6 months minimum follow-up; risk factor analysis

90 High dose rate brachytherapy (HDR BT) in the curative nonsurgical treatment of esophageal cancer (30 cases)

90 High dose rate brachytherapy (HDR BT) in the curative nonsurgical treatment of esophageal cancer (30 cases)

97 Curative irradiation for limited non small cell lung cancer with exclusive high dose rate brachytherapy (HDR BT) [28 patients

97 Curative irradiation for limited non small cell lung cancer with exclusive high dose rate brachytherapy (HDR BT) [28 patients