High-dose-rate Interstitial Brachytherapy Research Articles

Interfractional Variation of Treatment Delivery for High-Dose-Rate Interstitial Brachytherapy for Primary or Recurrent Gynecologic Malignancies: A Single-Institution Experience

For women who require high-dose-rate interstitial brachytherapy (HDR-ISBT) for primary or recurrent gynecologic malignancy, there can be significant interfractional variation from patient motion, post-implant swelling and organ filling. The purpose of this study was to evaluate the interfractional variation of dose distribution and displacement of catheters during HDR-ISBT in a single implant, consecutive day regimen. A total of 15 patients with primary or recurrent gynecologic malignancies who underwent HDR-ISBT were reviewed. Interstitial catheters and fiducials were placed under fluoroscopy and ultrasound guidance to confirm desired placement for clinical target volume (CTV) coverage and reproducibility. Patients underwent 4-5 treatments over 2-3 consecutive days. CT imaging was acquired on day of implant and days 2 and/or 3. Displacement of fiducials, their center of mass (CM) and self-consistency was calculated for each fraction. Additionally, the position of catheter tips and CTV’s relative to CM of fiducials were measured. The effects on dosimetric parameters such as dose covering 90% of high-risk CTV (D90), equivalent uniform BED (EUBED) and generalized biologically equivalent uniform dose (gBEUD) were compared for each fraction. 50 fiducials were tracked over 70 fractions. For a majority of patients (10 out of 15), the fiducial markers CM moved less than 0.2 cm. The positions of 278 catheters over the same fractions were measured relative to the fiducials CM and found to have an average interfractional movement of -0.06 +/- 0.31 cm. The CTV to needles interfractional shift was -0.09 +/- 0.36 cm. The average D90 for all fractions was 92.5 +/- 6.5% of the prescription dose (PD). The average gEUD across all patients was 1.57 +/- 0.19 and 18.44+/- 15.08 Gy/PD (a = -5 and 2, respectively). The average EUBED across all patients was 1.98+/- 0.16 and 2.43+/- 0.23 Gy/PD (α = 0.3 and 0.1, respectively). Volume integrated radiobiological metrics, gBEUD and EUBED showed very consistent effects for all implants. Center of mass for 3 or more markers seems a clinically acceptable reference for ensuring catheter tip and CTV positional interfractional reproducibility. Given the dose inhomogeneities accepted with HDR-ISBT, D90 is less sensitive than volume integrated metrics for describing the dose delivered. Combining the effects of a reproducibly accurate implant with unique identification of the importance of ‘hot’ sub-volumes is a promising method for improving patient outcomes with HDR-ISBT.

Three Dimensional Printed Individual Template Based 192ir High-Dose Rate Interstitial Brachytherapy for Central Recurrent Gynecologic Cancer: A Phase II Clinical Trial

To evaluate the feasibility, safety, and accuracy of three-dimensional (3D)-printed individual template (3D-PIT) based with HDR interstitial brachytherapy (HDR-IB) for pelvic central recurrent gynecologic cancer (CR-GYN). 32 patients diagnosed CR-GYN in our institution were received 192Ir HDR-IB. 3D-PIT technique was carried out for all these patients in our center. They underwent procedure that firstly simulation; then preplan; thirdly 3D template design and printing and fourthly interstitial 192Ir HDR brachytherapy operation. There are two types of individual 3D-PIT designed. Type I: transvaginal template/applicator, and Type II: transvaginal combined transperineal template. The prescription dose to GTV was 10-36Gy, 5-6Gy/fraction, 2-6f. Dose parameters were D90, D100, V100, conformal index, external index and homogeneity index of the target volume, and the dose received by 2cm3 of normal tissue of organs at risk (rectum, bladder, and intestine) were recorded. We compared the dose parameters of the treatment plan with the preplan. The short-term efficacy was evaluated by RECIST v1.1, and the adverse event was evaluated by CTCAE V4.0. In total 32 patients, 205 needles were inserted for 153 applications, The mean V100, D100, and D90 per fraction were 88.9%±9.8%,3.45Gy±0.54Gy, and 5.79 Gy±0.32Gy respectively; the mean D2cc of rectum, bladder and colon per fraction were 3.14Gy±0.23Gy, 3.76Gy±0.72Gy and 2.47Gy±0.34Gy respectively. The mean CI, EI, and HI were 0.59±0.12, 0.31±0.16, and 0.47±0.22. Dosimetry parameters comparison between preplan and treatment plan of 20/32 patients with Type II 3D-PIT based HDR-IB show that there were no statistically significant (P > 0.05) difference in GTV volume, V100, D100, D90, CI and HI. Treatment plan EI was lower than preplan, and the difference was statistically significant (P = 0.022). Median follow up time was 10 months (3–28 months). No severe complications of procedures occurred. Grade 3 or 4 late toxicities (fistula ) were observed in 3 patients (9%). The local response rate (CR + PR) was 84.4% (27/32) one month later completion of treatment. In addition, the median TTP was 15.4 months (95% CI 11.3- 19.6ms), 1 year and 2 year local control rate were 51.7% and 51.7%. 3D-PIT based with CT-simulator for HDR-IB for central r-GYN has good dosimetry parameters consistently, was clinically feasible and efficient, and complications did not increased significantly.

A 3D-printed patient-specific applicator guide for use in high-dose-rate interstitial brachytherapy for tongue cancer: a phantom study

A patient-specific applicator guide system (PSAG) for tongue-cancer high-dose-rate (HDR) interstitial brachytherapy (ISBT) was developed by utilizing a 3D printing technique. An effectiveness of the 3D-printed PSAG (3D-PSAG) was evaluated for HDR ISBT. Six patients with tongue cancer were retrospectively selected for this study. For each patient, a total of three virtual clinical target volumes (CTV) requiring the insertion of four catheters (CTV4), six catheters (CTV6), and eight catheters (CTV8) were defined. For each CTV, treatment plans were generated to deliver 45 Gy in nine fractions. The 3D-PSAG was fabricated using a 3D-printer and the patient’s CT-images. The resulting 3D-PSAG took the form of a shell conforming to the patient’s contours with tubes for catheter insertion. For each CTV, catheters were inserted into the phantom with and without the 3D-PSAG. After that, CT-images of the phantom with the inserted catheters were acquired. Differences between the planned positions and those of the actually inserted catheters were evaluated from the CT-images. Given the actual catheter insertion positions, the dose distributions were reconstructed and analyzed. The maximum positional errors with and without the 3D-PSAG were 0.2 mm and 4.5 mm, respectively. For CTV6, the D90% values of the original plan, the reconstructed plan with the 3D-PSAG, and the reconstructed plan without the 3D-PSAG, were 48.8 ± 1.7 Gy, 49.0 ± 2.9 Gy, and 45.6 ± 3.3 Gy, respectively. The D1cc values for the mandible were 51.3 ± 9.2 Gy, 61.6 ± 8.3 Gy, and 81.1 ± 16.7 Gy, respectively. The dose homogeneities in the CTVs into which the catheters had been inserted with the 3D-PSAG were always superior to those into which the catheters had been inserted without the 3D-PSAG. The present phantom study demonstrated the feasibility of more accurate interstitial tongue brachytherapy while simplifying the treatment process by utilizing the 3D-PSAG.

Image-guided high-dose-rate interstitial brachytherapy boost in the radical radiotherapy for a huge metastatic carcinoma of cervical lymph nodes from an unknown primary site

The purpose of this article was to report the treatment effect of image-guided high-dose-rate interstitial brachytherapy boost in the radical radiotherapy for a huge metastatic carcinoma of cervical lymph nodes from an unknown primary site. The patient was a 75-year-old male. A diagnostic biopsy showed metastatic squamous cell carcinoma and the tumour size was 7.5×6.5×11.5cm3 before treatment (N3; AJCC 7th). After external beam radiotherapy with a dose of 60Gy in 30 fractions, the residual tumour (6.2×4.7×6.0cm3) was treated with image-guided high-dose-rate interstitial brachytherapy boost under ultrasound guidance. The brachytherapy dose was 16Gy in four fractions of 4Gy each. Removal of the huge metastatic tumour was securely achieved by high dose rate interstitial brachytherapy guided with ultrasound scanning. The refractory tumour in the patients healed uneventfully after image-guided high-dose-rate interstitial brachytherapy without recurrence during the 24 months of follow-up. The image-guided high-dose-rate interstitial brachytherapy boost may be a proposed treatment strategy for metastatic carcinoma of cervical lymph nodes from an unknown primary site with radical radiotherapy, especially for huge residual tumour.

Nineteen-year single-center experience in 76 patients with penile cancer treated with high-dose-rate brachytherapy

PURPOSETo report the outcomes for 76 patients with penile cancer treated with high-dose-rate brachytherapy (HDR-BT) at a single institution. METHODSSeventy-six patients with penile cancer treated with HDR-BT in our department between October 1998 and September 2018 were analyzed. Seventy underwent interstitial HDR-BT (fractionation dose range of 3–3.5 Gy given twice a day with an interval of at least six hours between the fractions), and six underwent superficial treatment with mold applicators (fractionation dose range of 4–7 Gy given once or twice a week). RESULTSMedian follow-up was 76 months (7–204 months). In the whole group, 22/76 local failures (28.9%) were observed: 14/76 (18.4%) local recurrences and 8/76 (10.5%) cases of persistent disease. Median time to recurrence was 24 months (9–54 months). Inguinal lymph node metastases were observed in 18/76 cases (23.7%). Distant metastases occurred in 12/76 (15.8%) cases. Patients with local recurrence and persistent disease underwent salvage penectomies, except four who refused surgery and underwent a second course of interstitial HDR-BT. Five- and 10-year cause-specific survival were 85.0% and 77.8%, respectively. Local control at 5 and 10 years was 65.6%. Five- and 10-year penile preservation were 69.5% and 66.9%, respectively. There was no G3 or G4 acute toxicity. One urethral stenosis (1.3%) occurred in a patient with a T3 tumor and was treated successfully with dilatation. CONCLUSIONSHDR-BT provides good local control of penile cancer and is a good option for penis preservation therapy and in our experience achieves a penile preservation rate at 10 years of 66.9%.

Interstitial High Dose Rate Brachytherapy in the Treatment of Keloids: Moving towards a Volumetric Approach

Radiotherapy (RT) after surgical resection of keloids reduces the risk of local recurrence, but standardization of RT technique and dose are lacking. While other diseases treated with brachytherapy move from point to volume-based prescriptions, brachytherapy prescriptions for keloids are still standardly based on a single channel source prescribed to 0.5 cm depth. We investigated the dosimetry of a volume-based target definition for interstitial high dose rate brachytherapy treatment of keloids.

Clinical Outcomes of Patients Treated with Template Based High Dose Rate Interstitial Brachytherapy Boost for Gynaecological Cancers- A Retrospective Analyses

Patients with vault cancers, residual/recurrent disease post inadvertent hysterectomy, and advanced vaginal cancers form a significant patient population and are treated with radical radiotherapy, with or without concurrent chemotherapy. Radiotherapy comprises of external beam radiotherapy (EBRT) followed by a brachytherapy boost. The boost is delivered with high dose rate interstitial brachytherapy using templates if the disease is not amenable for intracavitary brachytherapy using vaginal cylinders. Reported literature in this group of patients is sparse, retrospective in nature and limited. In the recent past, our mono-institutional series has reported disease free (DFS) and overall survivals (OS) of 61.1% and 63.9% at 3-years respectively with grade 3-4 late bladder toxicities of 4.5% and late gastrointestinal (GI-rectal & small bowel) toxicities in 16% patients. On similar lines, we undertook another retrospective analysis of recently treated patients and performed a comparative analyses for further introspection in outcome.

A Plan Quality Assurance (QA) Method for HDR Breast Brachytherapy with Multi-Lumen Balloon Applicator and HDR Interstitial Prostate Brachytherapy

A challenge facing the physics community has been quick plan quality checks for high-dose-rate (HDR) brachytherapy treatment planning. This study aims to develop a QA method of manually verifying the planned treatment time from treatment planning system (TPS) for HDR breast brachytherapy using multi-lumen balloon applicators and HDR interstitial prostate brachytherapy.

Interstitial Brachytherapy for Accelerated Partial Breast Irrdiation or Boost Therapy in Early Breast Cancer

To evaluate the clinical outcome of early breast cancer (EBC) patients treated with high-dose-rate interstitial brachytherapy (HDR-IBT) based accelerated partial breast irradiation (APBI) or boost therapy plus whole breast radiation therapy (WBRT).

3D Printing-Based Prostate Phantom for Ultrasound-Guided Interstitial HDR Brachytherapy Training Program

This study proposes a cost effective prostate phantom to provide a better training opportunity to improve procedure proficiency, efficiency and insertion accuracy for ultrasound based HDR brachytherapy.Interstitial prostate brachytherapy requires sufficient experience for high quality implants and smooth operation. To improve needle insertion skills and become more familiar with the procedure workflow and equipment handling, practice is necessary. To assist trainees, a cost effective prostate phantom is desired. This study proposes a fabrication workflow to create a low-cost in-house prostate phantom by using 3D printing technology.

A Minor Adaptation in the Houdek Gynecological Applicator for Limited Intracavitary and Interstitial HDR Brachytherapy for Vault Cancers

The standard treatment for isolated vaginal vault recurrences post-surgical cervical and endometrial cancers, in previously unirradiated patients, is radio(chemo) therapy including brachytherapy (BT) boost. Radiation therapy would include standard external beam pelvic fields followed by BT boost depending on the residual disease. BT boost is challenging and depends on the residual disease and vault thickness. The vault disease usually has a supra-vaginal component which cannot be treated adequately with a simple intracavitary vault BT. These case scenarios would require interstitial BT. The classical interstitial approach includes the use of perineal templates (MUPIT, Syed Neblett etc.) which involves need of experience, increased number of needles and association with a learning curve. We attempted a minor adaptation in an existing Houdek Applicator (used for simple Intracavitary Vault BT) by introducing an acrylic cap fitted over the ring with multiple holes drilled for provision to introduce straight needles (18 Gauge stainless steel needles) through the cap as shown in figure 1. (Clockwise from top: 1. Central tandem and ring. 2. Acrylic caps 3. Ring fitted with the cap with needles) In addition to the tandem and ring channel, we made a customized acrylic cap to adapt to different ring diameters and drilled array of holes for central tandem and 2 circular planes of needles. After commissioning and dosimetric review, we evaluated its applicability. The assessment of technical feasibility, dosimetric parameters, and preliminary clinical outcome forms the basis of this report.

Comparative analysis of long-term results of high-tech external beam therapy and combined radiotherapy in patients with prostate cancer and high risk of progression

Background. Patients suffering from prostate cancer (PCa) with a high risk of progression need the most active treatment tactics. Escalation of radiation dose, larger daily fractions radiation therapy (including high-dose-rate interstitial brachytherapy (HDR-BT)) is a promising approach to the treatment of PCa. Objective of the study . Comparative assessment of the long-term treatment results of patients with PCa with a poor prognosis after external beam radiotherapy (EBRT) and combined radiation therapy, depending on risk factors. Materials and methods . 207patients who received a course EBRT and HDR-BT with EBRT (combined RT) on a radical program for the first detected PCa at the N.N. Alexandrov National Cancer Center of Belarus in 2013—2015 inclusive. All patients were belonged to the group of high and very high risk of progression according to the criteria of the NCCN (National Comprehensive Cancer Network), all were treated with neoadjuvated hormone therapy (medical or surgical castration). The patients were stratified into two groups: HDR-BT with EBRT and EBRT. When conducting combined RT, HDR-brachytherapy was performed in single fraction with a dose of 11.5 Gy, for EBRT it was used as a conventional fractionation (single dose of 2 Gy, total — 44 Gy) and hypofractionation (single dose of 3 Gy, total — 36 Gy). Patient that were not who not included in the combined RT protocol were treated with EBRT under a radical program in a total dose of 78—80 Gy. Results . It was established that in the group of patients after EBRT the median survival was not achieved, the 5-year adjusted survival (AS) was 85.2 + 5.6 %. In the combined RT group, the median survival was also not reached, the 5-year-old AS was 92.2 + 5.9 %. It was found that for the patients with a Gleason score of 7 or more, a significant difference in the AS index was obtained in favor of the HDR-BT with EBRT: the 5-year AS of patients of this subgroup who were exposed to combined RT was 84.6 + 9.8 %, while after EBRT, the 5-year-old AS was 71.0 + 11.2 %. In the subgroup of patients with Gleason sum 7—10, combined RT was associated with statistically significantly better long-term results in compared with EBRT. Conclusion. The application of the method of combined RTfor patients suffering from PCa with a high risk is characterized with satisfactory long-term treatment results.

HIGH-DOSE-RATE AND LOW-DOSE-RATE BRACHYTHERAPY AS MONOTHERAPY FOR CLINICALLY LOCALIZED PROSTATE CANCER

PURPOSE:To compare the outcome of high-dose-rate interstitial brachytherapy (HDR-BT) and low-dose-ratebrachytherapy (LDR-BT) as monotherapy for localized prostate cancer of low and intermediate risks progression. METHODS AND MATERIALS: The study included 165 patients with localized prostate cancer in low and intermediate progression risk groups. We compared 65 patients treated with HDR-BT and 100 patients with LDR-BT as monotherapy. LDR-BT treated advanced disease with more hormonal therapy than HDR-BT. All patients were in low and intermediate risk groups for prostate cancer progression. HDR-BT as monotherapy was delivered in 2 fractions of 15 Gy, two weeks apart. LDR-BT was performed in a standard mode of 145 Gy. The median observation was 32 months. All patients gave written informed consent. RESULTS: Overall biochemical free survival rate (BFSR) is 95,8%. There are 7 people having a growing prostatic specific antigen (PSA) while the case follow-up (in the group HDR-BT - 2 patients, LDR - 5 patients). Two recurrence cases with metastases in lymph nodes and bones were brought out as a result of 68Ga-PSMA PET examination in the group of HDR-BT. In 4 cases out of 5 LDR-BT, a local recurrence was detected (p=0,085). All cases of relapse were found in patients at intermediate risk (p = 0,041). LDR-BT showed a higher incidence of genitourinary (GU) toxicity grade >2 than that of HDR-BT in the acute phase and grade 1 toxicity in late phase. Accumulated incidence of late grade >2 GU and GU toxicity was equivalent between HDR-BT and LDR-BT. CONCLUSION: HDR-BT monotherapy showed an equivalent outcome to that of LDR-BT for low and intermediate risk patients. LDR-BT showed equivalent incidence of grade >2 late GU toxicities and higher grade >2 acute GU toxicity as that of HDR-BT as a monotherapy.

PO-100 HDR Interstitial brachytherapy in Recurrent Head and Neck cancer: An effective Salvage option

PO-100 HDR Interstitial brachytherapy in Recurrent Head and Neck cancer: An effective Salvage option

Image-guided high-dose-rate interstitial brachytherapy for recurrent rectal cancer after salvage surgery: a case report

Treatment options for patients with recurrent rectal cancer in pelvis represent a significant challenge because the balance of efficiency and toxicity needs to be pursued. This case report illustrates a treatment effect of image-guided high-dose-rate interstitial brachytherapy (HDR-ISBT) for locally relapsed rectal cancer after salvage surgery. A 61-year-old male who underwent laparoscopic high anterior resection (LAP-HAR) with D3 lymph node dissection as a primary treatment for rectal cancer (pT3N0M0, well-differentiated adenocarcinoma) had relapsed locally 8 months after initial surgery, for which he underwent salvage abdominal perineal resection (APR), followed by adjuvant 8 cycles of XELOX (capecitabine and oxaliplatin) chemotherapy. He developed pelvic recurrence 1 year after the second surgery. Image-guided HDR-ISBT was performed (30 Gy/5 fractions/3 days) followed by external beam radiation therapy with 39.6 Gy in 22 fractions. There were no severe complications related to salvage radiotherapy. CEA was decreased from 24.5 ng/ml to 0.7 ng/ml, 4 months after the salvage radiotherapy. Complete response was noted on follow-up MRIs done on 2, 5, 8, and 14 months after the treatment. Hence, HDR-ISBT appears to be effective for locally recurrent rectal cancer even after salvage surgery.

Efficacy and safety of percutaneous computed tomography-guided high-dose-rate interstitial brachytherapy in treatment of oligometastatic lymph node metastases of retroperitoneal space.

PurposeTo assess efficacy, safety, and outcome of computed tomography (CT)-guided high-dose-rate (HDR) interstitial brachytherapy in patients with oligometastatic lymph node metastases of the retroperitoneal space.Material and methods24 patients with a total of 47 retroperitoneal lymph node metastases from different primary tumors were treated with CT-guided interstitial brachytherapy using an 192Ir source (single fraction irradiation). Every three months after treatment, clinical and imaging follow-up were conducted to evaluate local control and safety.ResultsMedian follow-up was 9.6 months (range, 2.9-39.0 months). Local tumor control rate was 95.7%. The median diameter of the gross tumor volume was 2.2 cm (range, 1-8.6 cm), treated with a median D100 (minimal enclosing tumor dose) of 14.9 Gy (range, 4.5-20.6 Gy). One severe adverse event (grade three) was recorded.Cumulative median progression-free survival was 4.2 months (range, 1.4-23.7 months), and cumulative median overall survival after interstitial brachytherapy was 15.9 months (range, 3.8-39.0 months).ConclusionsCT-guided HDR interstitial brachytherapy is a safe and feasible method for local ablation of oligometastatic lymph node metastases of the retroperitoneal space, and might provide a well-tolerated additional therapeutic option in the multidisciplinary management of selected patients.

Use of interstitial brachytherapy in pelvic recurrence of cervical carcinoma: Clinical response, survival, and toxicity

PurposeThe purpose of this study was to evaluate clinical response, postrecurrence survival, disease-free survival (DFS), and toxicity related to reirradiation in pelvic recurrence of cervical carcinoma. Methods and MaterialsA retrospective cohort study of 45 women undergoing high-dose-rate interstitial brachytherapy (HDR-IB) was conducted from 1998 to 2014. Clinical information, as well as data on the malignancy, primary treatment, HDR-IB technique, and toxicity, was collected. Statistical analysis used chi-square or Fisher's exact test, Kaplan–Meier survival curves and log-rank test, and Cox regression, with p < 0.05 for significance. ResultsThere were 30 cases (67%) of complete clinical response, with a followup period of 9–129 months (20 alive, 10 died). The 5-year postrecurrence survival rate was 52%. Among 15 women without complete clinical response, the survival rate was low (<8 months). In the 30 women with complete clinical response, the 5-year DFS was 42%. All analyzed variables were not associated with survival. Ultrasonography-based needle placement was not associated with disease control or toxicity. Toxicity was reported in 23 women (51%) with 14 fistulas, unrelated to clinical response. However, there was a higher occurrence of fistula when chemotherapy was used. ConclusionsReirradiation using HDR-IB for pelvic recurrence of cervical carcinoma yielded a good complete clinical response rate. Postrecurrence survival and DFS rates were higher than expected, equivalent to salvage surgery, but with significant toxicity. Despite toxicity, this technique can be an alternative for selected cases.

Long-term results of multicatheter interstitial high-dose-rate brachytherapy for accelerated partial-breast irradiation

PurposeThe purpose of this study was to report the long-term results of women treated in one center with accelerated partial-breast irradiation (APBI) with interstitial high-dose-rate (HDR) brachytherapy. Materials and MethodsWe analyzed data from women treated in one center with adjuvant interstitial HDR brachytherapy for early-stage breast cancer. Treatment regimen was homogeneous for all women with treatment dose 32Gy in 8 fractions twice daily given to the tumor bed with interstitial HDR brachytherapy. ResultsAbout 364 women were treated with interstitial HDR brachytherapy as APBI from March 2000 to March 2014. Mean age at diagnosis was 62 years. Stage distribution was as follows: T1a = 12%, T1b = 33%, T1c = 40%, T2 = 14%, and Tis = 1%. 97% of patients were N0. 88% had invasive ductal carcinoma. 86% had positive hormone receptor status. 14 ipsilateral breast tumor recurrences were identified with 12 deemed local recurrences and 2 deemed to be second ipsilateral primaries. Actuarial 5-year and 10-year overall survival rates were 95.1% and 92.2%, respectively. Actuarial 5-year and 10-year local relapse-free survival rates were 96.2% and 88.8%, respectively. ConclusionsThe results of this previously unreported series of women treated with a homogeneous APBI method exclusively with interstitial HDR brachytherapy present further data justifying that in appropriately selected women, APBI with interstitial brachytherapy provides rates of local control and survival comparable with whole-breast irradiation.

Inversely and adaptively planned interstitial brachytherapy: A single implant approach

ObjectiveTo evaluate the efficacy, feasibility and safety of image-based, inversely and adaptively planned high-dose rate interstitial brachytherapy (HDR-ISBT) to treat advanced primary or recurrent gynecologic malignancy in a single implant, three-consecutive-day regimen. MethodsClinical demographics and outcome data were abstracted from all patients with primary and recurrent gynecologic malignancies who received HDR-ISBT boost from 2014 to 2017. Treatment consisted of a single implant (~7 Gy × 4 fractions) of interstitial needles using the Syed-Neblett template over a three-day hospital admission. CT-based (3D) simulation with inverse and adaptive planning was utilized for each fraction. MR prior to and MR immediately after external beam therapy were fused for HDR-ISBT target delineation. ResultsForty women with an overall median follow-up of 18 months (range: 6–54 months) received an HDR-ISBT boost. Of the 30 primary cases (83% cervix, 10% vaginal, 7% uterine), 44% had organ invasion (bladder, rectal or both) on MRI. Median coverage and dose are reported (V100: 98%, HR-CTV EQD2: 85.1 Gy, D90: 92 Gy). A significant association existed between rectal doses exceeding GEC-ESTRO recommendations (D2cc < 75 Gy) and the development of grade 3 gastrointestinal toxicity with a relative risk of 1.4 [1.1–1.8] (p = .046). Actuarial two-year overall survival (OS), local control (LC) and progression-free survival (PFS) were 81%, 81% and 64%, respectively. ConclusionsA four fraction, inversely and adaptively planned, single-implant approach of image-based HDR-ISBT provides excellent coverage, minimal toxicity and effective local control in patients with advanced and recurrent disease.

High-dose-rate brachytherapy monotherapy versus low-dose-rate brachytherapy with or without external beam radiotherapy for clinically localized prostate cancer

BackgroundTo compare the outcome of high-dose-rate interstitial brachytherapy (HDR-BT) monotherapy and low-dose-rate brachytherapy (LDR-BT) with or without external beam radiotherapy (EBRT) for localized prostate cancer. Methods and materialsWe compared 352 patients treated with HDR-BT as monotherapy (median follow-up time 84 months, NCCN risk classification; low: intermediate: high = 28:145:179) and 486 patients with LDR-BT with or without EBRT (90 months, 194:254:38). HDR-BT treated advanced disease with more hormonal therapy than LDR-BT. LDR-BT excluded patients with T3b–T4 tumor and initial PSA >50 ng/ml. Inverse probability of treatment weighting (IPTW) involving propensity scores was used to reduce background selection bias. ResultsThe actuarial 5-year biochemical failure-free survival rates (bNED) were 92.9% and 95.6% (p = 0.25) in the HDR-BT and LDR-BT groups, respectively, and it was 100% and 97.3% (p = 0.99) in the low-risk, 95.6% and 94.3% (p = 0.19) in the intermediate, 89.6% and 94.9% (p = 0.26) in the high-risk groups, and 93.1% and 94.9% (p = 0.98) in selected high-risk group excluding T3b-4 and initial PSA ≥50. IPTW correction also indicated no difference in bNED between LDR-BT and HDR-BT groups. LDR-BT showed a higher incidence of genitourinary (GU) toxicity grade ≥2 than that of HDR-BT in the acute phase and grade 1 toxicity in late phase. Acute GU toxicity grade ≥1 predicted late GU toxicity grade ≥2. External beam radiotherapy plus LDR-BT elevated GI toxicity than LDR-BT only group. Accumulated incidence of late grade ≥2 GU and GU toxicity was equivalent between HDR-BT and LDR-BT. No grade 4 or 5 toxicities were detected in either modality. ConclusionHDR-BT monotherapy showed an equivalent outcome to that of LDR-BT with or without EBRT for low-, intermediate- and selected high-risk patients. LDR-BT showed equivalent incidence of grade ≥2 late GI and GU toxicities and higher grade ≥2 acute GU toxicity as that of HDR-BT as a monotherapy.