Pulsed Dose Rate Brachytherapy Research Articles

Preoperative image-guided brachytherapy in early stage cervical cancers

ObjectiveTo examine the clinical results of a preoperative image-guided pulse-dose-rate brachytherapy (PDR-BT) in early stage cervical cancer. Materials/methodsWe examined the outcome of consecutive patients with early stage cervical cancer undergoing preoperative image-guided PDR-BT between 2004 and 2013 because of risk factors (lymphovascular embols and/or tumour>2cm). The objective was to deliver 60Gy to 100% of the intermediate risk clinical target volume. Brachytherapy was followed, 6–8weeks later, by a radical hysterectomy/bilateral salpingo-oophorectomy plus pelvic +/− para-aortic lymph node dissection. Patients with positive lymph nodes had postoperative chemoradiation. Results77 patients met the above criteria of preoperative PDR-BT. On hysterectomy specimen, 54 (70.1%) presented a complete histological response. Four (5.2%) had a tumour residuum⩾1cm. Median follow-up was 46.8months. 5-Year disease-free survival (DFS) rate was 84.4%. Only one local recurrence was observed. The presence of lymph nodal metastases, a tumour size>3cm and a brachytherapy/surgery time interval⩾9weeks correlated with a poorer DFS. Six postoperative complications were encountered (7.8%). Total reference air kerma correlated with late vaginal toxicity (p=0.02). ConclusionsA preoperative image-guided PDR-BT was safe and effective. Predictive factors for survival and toxicity were evidenced.

Clinical outcome of interstitial pulsed dose rate brachytherapy in multimodality treatment of locally advanced primary or recurrent rectal and sigmoid cancer with high risk of incomplete microscopic resection

Objective: To evaluate the role of interstitial pulsed dose rate brachytherapy (PDR-BT) in multimodality treatment of locally advanced primary or recurrent rectal and sigmoid cancer with high risk of microscopic incomplete resection (R1).Methods and material: A total of 73 consecutive patients (recurrent/primary: 40/33) were treated with PDR-BT between 2001 and 2010. Patients received preoperative external beam radiotherapy (EBRT) and concomitant chemotherapy. Following resection of the tumor and the involved pelvic organs, a median of four (3–8) catheters were sutured to the tumor bed with a distance of approximately 1 cm between the catheters. A target respecting the catheters with a margin of 5 mm was contoured on computed tomography (CT) and three-dimensional (3D) dose planning with a planning aim for BT of D90 > 30 Gy, (0.6 Gy/pulse, 1 pulse/h) was performed. Previously irradiated patients (27%) underwent surgery that was directly followed by PDR-BT. Postoperative EBRT was then applied to the tumor bed 3–5 weeks after PDR-BT.Results: A total of 23 patients (31%) received a radical resection (R0) and 45 patients (62%) received an R1 resection. Five patients (7%) received a macroscopic incomplete resection (R2). The five-year overall survival was 33%. Local control at five years was 67% for patients who received a R0 resection and 32% for patients who received an R1 resection. The five-year actuarial risk of a grade 3–4 BT-related complication was 5%.Conclusions: Meaningful disease control and survival can be obtained at an acceptable rate of late morbidity in selected patients with locally advanced primary and recurrent rectal or sigmoid cancer using (chemo) RT, extensive surgery and PDR-BT when a high risk of an R1 resection is expected.

Long term experience with 3D image guided brachytherapy and clinical outcome in cervical cancer patients

Background and purposeTo report our 10years’ experience and learning curve of the treatment of cervical cancer patients with chemo radiotherapy and MRI (or CT in 9 selected patients) guided brachytherapy using pulsed dose rate (PDR) brachytherapy (BT). Methods and materialsHundred and seventy consecutive patients with cervical cancer FIGO stage IB–IVB (without metastases beyond the para-aortic nodal region) were treated in our institute between 2002 and 2012. Patients received external beam radiotherapy (nodal boost to the lymph nodes positive at diagnosis)±chemotherapy followed by a pulsed or low dose rate brachytherapy boost. MRI (or CT) images were taken with the applicator in situ. The first 16 patients were treated according to X-ray-based plans, optimized on MRI. High-risk CTV, intermediate-risk CTV, bladder, rectum and sigmoid were retrospectively contoured according to the GEC-ESTRO recommendations. In all other patients, treatment plans were optimized after delineation of the target volumes and organs at risk at MRI (or CT). Doses were converted to the equivalent dose in 2Gy (EQD2) by applying the linear quadratic model. The median age of the patients was 55years (range 16–88). 41% had stage III or IV disease. Of the 170 patients, 91 patients had on imaging metastatic lymph nodes at diagnosis (62 patients pelvic lymph node involvement and 29 para-aortic). In 27 (16%) patients the intracavitary technique was combined with interstitial brachytherapy. ResultsThe mean D90 and D100 for the high-risk CTV were 84.8±8.36Gy and 67.5±6.29Gy for the entire patient group. Mean D90 and D100 values for the IR CTV were 68.7±5.5Gy and 56.5±6.25Gy. There was an important learning curve between both patient groups, with an increase in mean D90 of 75.8Gy for the first 16 patients compared to 85.8Gy for the second group. At the same time, the mean dose to 2cm3 of bladder and sigmoid decreased from 86.1Gy to 82.7Gy and from 70Gy to 61.7Gy, respectively. At a median follow-up of 37months (range 2–136months), local control rate for all patients was 96%, the regional control (pelvic and para-aortic) rate 81% and crude disease free survival rate 55%. The overall survival at 5years is 65%. The higher dose to the target volume resulted in an increase in local control from 88% in the first 16 patients compared to 97% in the second patient group. Regarding late toxicity, 21 patients (12%) presented grade 3–4 late morbidity. Rectal, urinary, sigmoid and vaginal morbidity was 5%, 6%, 2% and 5%, respectively. A correlation between rectal D2cm3 >65Gy and grade >3 late morbidity was found (p=0.006). ConclusionAlthough the majority of the patients presented with locally advanced carcinoma, excellent local and regional control rates were achieved. Rectal, urinary, sigmoid and vaginal grade 3–4 morbidity was 5%, 6%, 2% and 5%, respectively. A correlation between rectal D2cm3 >65Gy and grade >3 late morbidity was found (p=0.006).

Clinical Evidence after Brachyterapy Re-Irradiation in Head and Neck and Upper Respiratory Tract

Clinical Evidence after Brachyterapy Re-Irradiation in Head and Neck and Upper Respiratory Tract

Outcome of Patients with Early-Stage Cervical Cancer Treated with Preoperative Image-Guided Pulse-Dose Rate Brachytherapy Followed by Surgery

Outcome of Patients with Early-Stage Cervical Cancer Treated with Preoperative Image-Guided Pulse-Dose Rate Brachytherapy Followed by Surgery

Pulsed-dose-rate peri-operative brachytherapy as an interstitial boost in organ-sparing treatment of breast cancer.

PurposeTo evaluate peri-operative multicatheter interstitial pulsed-dose-rate brachytherapy (PDR-BT) with an intra-operative catheter placement to boost the tumor excision site in breast cancer patients treated conservatively.Material and methodsBetween May 2002 and October 2008, 96 consecutive T1-3N0-2M0 breast cancer patients underwent breast-conserving therapy (BCT) including peri-operative PDR-BT boost, followed by whole breast external beam radiotherapy (WBRT). The BT dose of 15 Gy (1 Gy/pulse/h) was given on the following day after surgery.ResultsNo increased bleeding or delayed wound healing related to the implants were observed. The only side effects included one case of temporary peri-operative breast infection and 3 cases of fat necrosis, both early and late. In 11 patients (11.4%), subsequent WBRT was omitted owing to the final pathology findings. These included eight patients who underwent mastectomy due to multiple adverse prognostic pathological features, one case of lobular carcinoma in situ, and two cases with no malignant tumor. With a median follow-up of 12 years (range: 7-14 years), among 85 patients who completed BCT, there was one ipsilateral breast tumor and one locoregional nodal recurrence. Six patients developed distant metastases and one was diagnosed with angiosarcoma within irradiated breast. The actuarial 5- and 10-year disease free survival was 90% (95% CI: 84-96%) and 87% (95% CI: 80-94%), respectively, for the patients with invasive breast cancer, and 91% (95% CI: 84-97%) and 89% (95% CI: 82-96%), respectively, for patients who completed BCT. Good cosmetic outcome by self-assessment was achieved in 58 out of 64 (91%) evaluable patients.ConclusionsPeri-operative PDR-BT boost with intra-operative tube placement followed by EBRT is feasible and devoid of considerable toxicity, and provides excellent long-term local control. However, this strategy necessitates careful patient selection and histological confirmation of primary diagnosis.

Innovative technique for pulsed dose rate brachytherpy in mobile and base of tongue carcinomas

Purpose Continuous low-dose rate interstitial brachytherapy using Pernot's plastic tubes afterloading with loop technique was a well-established treatment modality for localized tongue carcinomas. With the stop sale of iridium wires we must use pulse-dose rate brachytherapy, and replace each loop is by two straight catheters, leading to underdosage at the top of the clinical target volume. To obtain a correct clinical target volume coverage, dwell time of distal dwell positions must be increased creating a risk of mucosa necrosis by overdose. We evaluated the use of a bolus in pulsed-dose rate brachytherapy to mimic the continuous low-dose rate iridium wire loop technique. Materials and methods Three consecutive patients with base of tongue carcinomas referred for interstitial brachytherapy were included. We used pulsed-dose rate brachytherapy with interstitial plastic straight. We replaced the loop technique with catheters protruding above the tongue to ensure that the distal dwell position was above the tongue surface. Catheters were protruding through plastic buttons placed at the top end of the catheter for the control patient and plastic button more one bolus (5 mm-thickness) for two experimental patients. The Paris system for dosimetry was applied. Dose distribution was optimized by increased dwell time for the three distal dwell positions. Dosimetric comparison was performed between control patient and the two experimental patients. Results Six catheters were implanted for the control patient and the first experimental patient and 4 for the second. Ratio between dwell time for the distal dwell positions and the other positions was 2,6 for the control patient, 1,9 and 1,4 for the first and second experimental patients respectively, as to cover at least 98% of the clinical target volume. All patients could receive the whole pulsed-dose rate treatment and the bolus was well tolerated. Conclusion Pulsed-dose rate brachytherapy with bolus application could be an effective and safe alternative to continuous low dose rate iridium wire technique for localized tongue carcinomas treatment.

A review of the clinical experience in pulsed dose rate brachytherapy.

Pulsed dose rate (PDR) brachytherapy is a treatment modality that combines physical advantages of high dose rate (HDR) brachytherapy with the radiobiological advantages of low dose rate brachytherapy. The aim of this review was to describe the effective clinical use of PDR brachytherapy worldwide in different tumour locations. We found 66 articles reporting on clinical PDR brachytherapy including the treatment procedure and outcome. Moreover, PDR brachytherapy has been applied in almost all tumour sites for which brachytherapy is indicated and with good local control and low toxicity. The main advantage of PDR is, because of the small pulse sizes used, the ability to spare normal tissue. In certain cases, HDR resembles PDR brachytherapy by the use of multifractionated low-fraction dose.

Comparison of CT-based volumetric dosimetry with traditional prescription points in the treatment of cervical cancer with PDR brachytherapy.

The traditional use of two-dimensional geometric prescription points in intracavitary brachytherapy planning for locally advanced cervical cancer is increasingly being replaced by three-dimensional (3D) planning. This study aimed to directly compare the two planning methods to validate that CT planning provides superior dosimetry for both tumour and organs at risk (OARs) in our department. The CT planning data of 10 patients with locally advanced cervical cancer was audited. For each CT dataset, two new brachytherapy plans were created, comparing the dosimetry of conventional American Brachytherapy Society points and 3D-optimised volumes created for the high-risk clinical target volume (HR CTV) and OARs. Total biologically equivalent doses for these structures were calculated using the modified EQD2 formula and comparative dose-volume histogram (DVH) analysis performed. DVH analysis revealed that for the 3D-optimised plans, the prescription aim of D90 ≥ 100% was achieved for the HR CTV in all 10 patients. However, when prescribing to point A, only 50% of the plans achieved the minimum required dose to the HR CTV. Rectal and bladder dose constraints were met for all 3D-optimised plans but exceeded in two and one of the conventional plans, respectively. This study confirms that the regionally relevant practice of CT-based 3D-optimised planning results in improved tumour dose coverage compared with traditional points-based planning methods and also improves dose to the rectum and bladder.

TU-AB-201-01: A Comprehensive Planning Comparison Study Between a Novel Direction Modulated Brachytherapy Tandem Applicator and Conventional T&R Applicator for Image Guided Cervical Cancer Brachytherapy

Purpose: To demonstrate that utilization of a novel, intensity modulation capable, direction modulated brachytherapy (DMBT) tandem applicator can improve plan quality compared with conventional T&R applicator during an image guided cervical cancer brachytherapy. Methods: 45 cervical cancer patients treated with PDR brachytherapy were reviewed. Of them, a) 27 were treated using T&R only, b) 9 were treated using T&R with needles attached to the ring, and c) the remaining 9 were treated using T&R with needles attached to the ring (AN) as well as additional free-hand-loaded needles (FN). The DMBT tandem design has 6 peripheral holes of 1.3-mm diameter, grooved along a nonmagnetic tungsten alloy rod, enclosed in a plastic sheath with total 6.0-mm diameter. An in-house-coded inverse planning system was used for planning DMBT and T&R cases. All typical clinical constraints including OAR dose limits, dwell times, and loading patterns were respected. For the DMBT and T&R applicators, the plans were optimized with the same conventional ring in place, but repeatedly planned with and without AN/FN needles. All generated plans were normalized to the same D90 of the clinically treated plans. Results: For the plans in category a), DMBT generally outperformed T&R with average reduction in D2cc of −2.39%, −5.21%, and −2.69% for bladder, rectum, and sigmoid, respectively. For the plans in category b) and c), DMBT generally outperformed T&R if the same needles in AN/FN were utilized in both cases with average reduction in D2cc of −1.82%, −3.40%, and −6.04%, respectively. For the cases where the needles were not utilized for both applicators, an average D2cc reduction of −7.45%, −7.61%, and 17.47% were observed, respectively. Conclusions: Under the same clinical conditions, with/without needles, the DMBT applicator tends to generate more favorable plans compared with the conventional T&R applicator, and hence, is a promising technology.

Concomitant Chemoradiotherapy With Image-guided Pulsed Dose Rate Brachytherapy as a Definitive Treatment Modality for Early-stage Cervical Cancer

Concurrent chemoradiotherapy (CRT) is the standard of care for patients with bulky cervical cancer. This study aimed to determine the feasibility, tolerance, and effectiveness of pulsed dose rate (PDR) image-guided brachytherapy (IGBT), utilizing magnetic resonance imaging (MRI) planning after CRT for stages IB2 and II cervix cancer patients. This study planned to include patients with histologically confirmed stage IB2 and II cervical cancer who were treated with CRT followed by a PDR IGBT boost from January 2009 to December 2009 in our institution. All patients had at least a partial response after CRT before IGBT. The institutional review board approved the study. Patients received a 45-Gy external beam radiotherapy (EBRT) to the pelvis with concomitant weekly cisplatin (40 mg/m) for 5 cycles. All patients then underwent reimaging using MRI before BT. The IGBT boost was accomplished with one insertion using an MRI-compatible tandem and ovoid applicator delivering 30 to 35 Gy to a high-risk clinical target volume. Treatment-induced adverse events (AEs), dose parameters, local control, progression-free survival, and overall survival are reported. Forty patients were included in this study, with ages ranging from 31 to 65 years (median age, 45 y). Of all the patients, 12.5% and 5% experienced grade 3 to 4 acute gastrointestinal and genitourinary AEs, respectively, and 2.5% and 2.5% had grade 3 to 4 chronic gastrointestinal and genitourinary AEs, respectively. Within a median follow-up of 30 months (range, 7 to 40 mo), local control was 90%, progression-free survival was 87.5%, and overall survival was 100%. Intracavitary MRI PDR-IGBT boost after CRT is a feasible, tolerable, and effective treatment modality for patients with stages IB2 and II cervical cancer.

Clinical Experience with Pulse Dose Rate Brachytherapy for Conservative Treatment of Penile Carcinoma and Comparison with Historical Data of Low Dose Rate Brachytherapy

AimsTo assess the efficacy of pulse dose rate (PDR) interstitial brachytherapy in the treatment of carcinoma of the penis and to compare with historical data of low dose rate (LDR) brachytherapy. Materials and methodsWe reviewed the clinical records of 27 consecutive patients treated in our institution with exclusive PDR brachytherapy for a squamous cell carcinoma of the penis. The median tumour greatest diameter was 20 mm (range: 10–50 mm). Twenty-three patients (85%) had tumours limited to the glans and/or prepuce and four patients (15%) also had inguinal lymph node metastases. Implantations were carried out according to the Paris system and treatments were delivered with PDR brachytherapy. ResultsThe median brachytherapy dose was 60 Gy (range: 60–70 Gy). The median treated volume was 28 cm3 (range: 8–62 cm3). The median reference isodose rate was 0.4 Gy/pulse/h (range: 0.4–0.5 Gy/pulse/h). The median number of pulses was 150 (range: 120–175 pulses). With a median follow-up of 33 months (range: 6–64 months), tumour relapses in the penis were reported in four patients (15%). All patients with only local relapse (n = 3) were successfully salvaged with partial amputation. The estimated overall survival rate at 3 years was 95% (95% confidence interval: 83–100%). No grade 3 or more acute reaction was observed. Delayed ulcerations and stenoses requiring at least one meatal dilatation were reported in two (9%) and five (22%) patients without local relapse. The treated volume was significantly correlated to the risk of clinically relevant delayed toxicity. ConclusionsThe efficacy/toxicity results of PDR brachytherapy for the treatment of penile carcinoma are comparable with those obtained with LDR brachytherapy in historical cohorts.

Chirurgie exclusive ou curiethérapie utérovaginale préopératoire pour cancer du col utérin de stade IB1 : profil des toxicités

ObjectiveTo assess toxicity profile in two stage-IB1 cervical cancer treatment strategies: surgery with and without preoperative uterovaginal pulsed dose-rate brachytherapy. MethodsA retrospective study included 45 patients presenting stage-IB1 cervical cancer without pelvic lymph-node invasion, between 2009 and 2011: 25 treated by colpohysterectomy alone (group A) and 20 with preoperative uterovaginal pulsed dose-rate brachytherapy (group B). The median follow-up was 45 and 39 months (group A and B). ResultsGroups were comparable for age (median, 46.9 vs 47.6 years), histologic type (52% vs 65% squamous cell carcinoma) and tumor size (68% vs 60%, <2cm). In postoperative year 1, rates of urinary, digestive and gynaecological disorder were 39.1%, 8.7% and 15% respectively in group A versus 36.8%, 5.3% and 31.6% in group B and in year 2, 5.9%, 8.4% and 15% versus 5.6%, 5.1% and 27.8%. Discussion and conclusionThe present study comparing two stage-IB1 cervical cancer treatment strategies found no significant difference in early or late complications. In 2 months, there was greater grade-3 urinary toxicity (21.1%) and sexual disorder (15.8%) with preoperative brachytherapy but no significant difference. Exclusive surgery is probably preferable for the patient's quality of life.

Interstitial pulsed-dose-rate brachytherapy for the treatment of squamous cell anal carcinoma: A retrospective single institution analysis.

To examine the outcome of patients receiving interstitial pulsed-dose-rate brachytherapy (PDR-BT) after pelvic radiation therapy for treatment of an anal squamous cell carcinoma. Twenty-one patients were identified: 13, six, and two with stages I, II, and III tumors, respectively. After receiving received pelvic irradiation +/- concurrent chemotherapy, patients were delivered a PDR-BT boost to the residual tumor, with intention to deliver a minimal total dose of 60 Gy. The greatest dimension of residual tumor at the time of brachytherapy procedure was 12.5 mm (range: 0-20 mm). Brachytherapy implantation was performed according to the Paris system, only one plane implant being used. Median dose delivered through BT was 20 Gy (range: 10-30 Gy). Median number of pulses was 48 (range: 20-80 pulses). Median treated volume was 9 cm(3) (range: 5-16 cm(3)). Median dose per pulse was 40 cGy (range: 37.5-50 cGy). No Grade 3 or more acute toxicity was reported. No Grade 3 or more delayed toxicity was seen among 18 patients with more than 6 months follow-up. Median followup was 47 months (range: 6-73 months). Twenty patients (95%) were alive at last follow-up. Tumor relapses were experienced in four patients (19%), including local relapse in three patients (14%). With almost 4 years median followup, this study confirms previous data suggesting that PDR-BT is effective and safe in this indication. Local control rate and toxicity were in the range of what was seen with continuous low-dose-rate BT.

Implementation of the global risk analysis in pulsed-dose rate brachytherapy: Methods and results

PurposeTo report the application of the global risk analysis (GRA) in the pulsed-dose rate (PDR) brachytherapy workflow. Material and MethodsAnalyses were led by a multidisciplinary working group established within the unit with the guidance of a quality engineer. First, a mapping of hazardous situations was developed as a result of interactions between the patient workflow for a treatment using PDR brachytherapy split into 51 sub-phases with a comprehensive list of the hazards that he/she faces (44). Interactions, when relevant, were sorted by level of priority: to be treated immediately, secondarily (the group is not entitled to treat the situation), or later (safe situation). Secondly, for each high priority dangerous situation, scenarios were developed to anticipate their potential consequences. Criticality was assessed, using likelihood and severity scales and a matrix, which allocated risks into categories: acceptable (C1), tolerable under control (C2) and unacceptable (C3). Then, corrective actions were proposed and planned when relevant, after assessment of their feasibility with a scale of effort. Finally, the criticality of the scenarios was reevaluated, taking into account the implementation of these actions, leading to a residual risk mapping, which could trigger additional proposals of actions. ResultsTwo thousand one hundred and eighty-four potential interactions between the list of hazards and the workflow were analyzed. Mapping of dangerous situations identified 213 relevant interactions, from which 61 were considered with high priority. One hundred and twenty-six scenarios were generated: 68 with a low criticality (74.3%), 58 with an intermediate score (25.7%). No scenario with the highest criticality was individualized. Twenty-one corrective actions were planned. Mapping of residual risk resulted in the disappearance of most C2 risks, leaving 5 C2 scenarios (4%), for which four monitoring indicators were implemented in addition to the corrected actions decided on. ConclusionThe implementation of the GRA appeared feasible, and led to implement 21 corrective actions, based on scenarios and not on incidents.

Salvage brachytherapy in combination with interstitial hyperthermia for locally recurrent prostate carcinoma following external beam radiation therapy: a prospective phase II study.

Optimal treatment for patients with only local prostate cancer recurrence after external beam radiation therapy (EBRT) failure remains unclear. Possible curative treatments are radical prostatectomy, cryosurgery, and brachytherapy. Several single institution series proved that high-dose-rate brachytherapy (HDRBT) and pulsed-dose-rate brachytherapy (PDRBT) are reasonable options for this group of patients with acceptable levels of genitourinary and gastrointestinal toxicity. A standard dose prescription and scheme have not been established yet, and the literature presents a wide range of fractionation protocols. Furthermore, hyperthermia has shown the potential to enhance the efficacy of re-irradiation.Consequently, a prospective trial is urgently needed to attain clear structured prospective data regarding the efficacy of salvage brachytherapy with adjuvant hyperthermia for locally recurrent prostate cancer. The purpose of this report is to introduce a new prospective phase II trial that would meet this need. The primary aim of this prospective phase II study combining Iridium-192 brachytherapy with interstitial hyperthermia (IHT) is to analyze toxicity of the combined treatment; a secondary aim is to define the efficacy (bNED, DFS, OS) of salvage brachytherapy. The dose prescribed to PTV will be 30 Gy in 3 fractions for HDRBT, and 60 Gy in 2 fractions for PDRBT. During IHT, the prostate will be heated to the range of 40–47°C for 60 minutes prior to brachytherapy dose delivery. The protocol plans for treatment of 77 patients.

Impact of treatment time and dose escalation on local control in locally advanced cervical cancer treated by chemoradiation and image-guided pulsed-dose rate adaptive brachytherapy

PurposeTo report the prognostic factors for local control in patients treated for locally advanced cervical cancer with image guided pulsed-dose rate brachytherapy. Materials/methodsPatients treated with curative intent by a combination of external beam radiotherapy and pulsed-dose rate brachytherapy were selected. Local failure was defined as any relapse in the cervix, vagina, parametria, or uterus during follow-up. Prognostic factors were selected based on log rank tests and then analyzed with a Cox model. Dose/effect correlations were performed using the probit model. ResultsTwo hundred and twenty-five patients treated from 2006 to 2011 were included. According to the FIGO classification, 29% were stage IB, 58% stage II, 10% stage III, and 3% stage IVA; 95% received concomitant chemotherapy. Thirty patients were considered having incomplete response or local failure. Among the selected parameters, D90 for HR-CTV, D90 for IR-CTV, the overall treatment time, the TRAK, and the HR-CTV volume appeared significantly correlated with local control in univariate analysis. In multivariate analysis, overall treatment time >55days and HR-CTV volume >30cm3 appeared as independent. The probit analysis showed significant correlations between the D90 for both CTVs, and the probability of achieving local control (p=0.008 and 0.024). The thresholds to reach to warrant a probability of 90% of local control were 85Gy to the D90 of the HR-CTV and 75Gy to 90% of the IR-CTV (in 2Gy equivalent, α/β=10). To warrant the same local control rate, the D90 HR-CTV should be significantly increased in stage III–IV tumors, in case of HR-CTV >30cm3, excessive treatment time, or tumor width at diagnosis >5cm (97, 92, 105, and 92Gy respectively). ConclusionsOverall treatment time and HR-CTV volume were independent prognostic factors for local control. The D90 for HR and IR CTV were significantly correlated with local control, and D90 HR-CTV should be adapted to clinical criteria.

A real-time quality assurance instrumented phantom for HDR and PDR brachytherapy

A real-time quality assurance instrumented phantom for HDR and PDR brachytherapy

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.

Dose rate in brachytherapy using after-loading machine: Pulsed or high-dose rate?

Since February 2014, it is no longer possible to use low-dose rate 192iridium wires due to the end of industrial production of IRF1 and IRF2 sources. The Brachytherapy Group of the French society of radiation oncology (GC-SFRO) has recommended switching from iridium wires to after-loading machines. Two types of after-loading machines are currently available, based on the dose rate used: pulsed-dose rate or high-dose rate. In this article, we propose a comparative analysis between pulsed-dose rate and high-dose rate brachytherapy, based on biological, technological, organizational and financial considerations.