Postoperative brachytherapy for endometrial cancer using a ring applicator

Vaginal cuff brachytherapy in endometrial cancer - a technically easy treatment?

Endometrial cancer (EC) is one of the most common gynecological cancers among women in the developed countries. Vaginal cuff is the main location of relapses after a curative surgical procedure and postoperative radiation therapy have proven to diminish it. Nevertheless, these results have not translated into better survival results. The preeminent place of vaginal cuff brachytherapy (VCB) in the postoperative treatment of high- to intermediate-risk EC was given by the PORTEC-2 trial, which demonstrated a similar reduction in relapses with VCB than with external beam radiotherapy (EBRT), but VCB induced less late toxicity. As a result of this trial, the use of VCB has increased in clinical practice at the expense of EBRT. A majority of the clinical reviews of VCB usually address the risk categories and patient selection but pay little attention to technical aspects of the VCB procedure. Our review aimed to address both aspects. First of all, we described the risk groups, which guide patient selection for VCB in clinical practice. Then, we depicted several technical aspects that might influence dose deposition and toxicity. Bladder distension and rectal distension as well as applicator position or patient position are some of those variables that we reviewed.

American Brachytherapy Task Group Report: Adjuvant vaginal brachytherapy for early-stage endometrial cancer: A comprehensive review

This article aims to review the risk stratification of endometrial cancer, treatment rationale, outcomes, treatment planning, and treatment recommendations of vaginal brachytherapy (VBT) in the postoperative management of endometrial cancer patients. The authors performed a thorough review of the literature and reference pertinent articles pertaining to the aims of this review. Adjuvant VBT for early-stage endometrial cancer patients results in very low rates of vaginal recurrence (0-3.1%) with low rates of late toxicity which are primarily vaginal in nature. Post-Operative Radiation Therapy in Endometrial Cancer 2 (PORTEC-2) supports that VBT results in noninferior rates of vaginal recurrence compared to external beam radiotherapy for the treatment of high-intermediate risk patients. VBT as a boost after external beam radiotherapy, in combination with chemotherapy, and for high-risk histologies have shown excellent results as well though randomized data do not exist supporting VBT boost. There are many different applicators, dose-fractionation schedules, and treatment planning techniques which all result in favorable clinical outcomes and low rates of toxicity. Recommendations have been published by the American Brachytherapy Society and the American Society of Radiation Oncology to help guide practitioners in the use of VBT. Data support that patients and physicians prefer joint decision making regarding the use of VBT, and patients often desire additional treatment for a marginal benefit in risk of recurrence. Discussions regarding adjuvant therapy for endometrial cancer are best performed in a multidisciplinary setting, and patients should be counseled properly regarding the risks and benefits of adjuvant therapy.

Dosimetric advantages of using multichannel balloons compared to single-channel cylinders for high-dose-rate vaginal cuff brachytherapy

PURPOSE

To evaluate the dosimetric advantages of using multichannel balloons (MCBs) vs. single-channel cylinders (SCCs) for high-dose-rate vaginal cuff brachytherapy.

METHODS AND MATERIALS

A total of 91 consecutive high-dose-rate vaginal cuff brachytherapy including 45 MCB and 46 SCC treatments were reviewed. The clinical target volume (CTV) was defined as a 0.5-cm uniform expansion of the applicator surface from vaginal apex for 3 cm. For dosimetric comparison, we normalized prescription dose per fraction to 700 cGy and optimized each plan to cover at least 90% of CTV. CTV-1 cm, the true vaginal cuff volume, was defined as proximal 1 cm of CTV from vaginal apex. Four quality indices including conformity index (CI), dose homogeneity index, dose nonuniformity index, and overdose index were compared.

RESULTS

The CTV and CTV-1 cm were significantly larger for MCB cases compared to SCC cases. Evaluating CTV coverage, the mean dose homogeneity index and dose nonuniformity index were superior for MCB than SCC. No differences were noted regarding CI and overdose index between MCB and SCC cases. However, focusing on CTV-1 cm, the difference of CI became significant in favor of MCB cases. In addition, the mean point dose at 0.5-cm depth from the apex was significantly lower in SCC cases compared to cases by MCB treatment, indicating inadequate vaginal apex coverage by SCC treatment.

CONCLUSIONS

Compared to SCC, MCB treats a larger volume and offers a more conformal and homogeneous target coverage. In addition, a lower dose at the vaginal apex due to SCCs source anisotropy can be minimized.

Vaginal brachytherapy for postoperative endometrial cancer: 2014 Survey of the American Brachytherapy Society

PURPOSE

Report current practice patterns for postoperative endometrial cancer emphasizing vaginal brachytherapy (VBT).

METHODS AND MATERIALS

A 38-item survey was e-mailed to 1,598 American Brachytherapy Society (ABS) members and 4,329 US radiation oncologists in 2014 totaling 5,710 recipients. Responses of practitioners who had delivered VBT in the previous 12 months were included in the analysis. Responses were tabulated to determine relative frequency distributions. χ(2) analysis was used to compare current results with those from the 2003 ABS survey.

RESULTS

A total of 331 respondents initiated the VBT survey, of whom 289 (87.3%) administered VBT in the prior 12 months. Lymph node dissection and number of nodes removed influenced treatment decisions for 90.5% and 69.8%, respectively. High-dose-rate was used by 96.2%. The most common vaginal length treated was 4 cm (31.0%). Three-dimensional planning was used by 83.2% with 73.4% of those for the first fraction only. Doses to normal tissues were reported by 79.8%. About half optimized to the location of dose specification and/or normal tissues. As monotherapy, the most common prescriptions were 7 Gy for three fractions to 0.5-cm depth and 6 Gy for five fractions to the surface. As a boost, the most common prescriptions were 5 Gy for three fractions to 0.5-cm depth and 6 Gy for three fractions to the vaginal surface. Optimization points were placed at the apex and lateral vagina by 73.1%. Secondary quality assurance checks were performed by 98.9%.

CONCLUSIONS

VBT is a common adjuvant therapy for endometrial cancer patients, most commonly with HDR. Fractionation and planning processes are variable but generally align with ABS recommendations.

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.