Late G2 vagina toxicity in post-operative endometrial carcinoma is associated with a 68 Gy dose equivalent to 2 Gy per fraction(α/β=3Gy) at 2 cm3 of vagina

Partial-Length Treatment With Brachytherapy in Patients With Endometrial Cancer With High-Risk Features Is as Effective as Full-Length Vaginal Brachytherapy but With Reduced Toxicity

PURPOSE

Full-length vaginal (FLV) brachytherapy for patients with endometrial cancer and high-risk features should be considered as per the American Brachytherapy Society to reduce distal vaginal recurrence in patients with endometrial cancers with papillary serous/clear cell histologies, grade 3 status, or extensive lymphovascular invasion. We sought to investigate this patient population and report outcomes of treatment with high-dose-rate (HDR) brachytherapy in women treated with FLV brachytherapy versus partial-length vaginal (PLV) brachytherapy.

METHODS AND MATERIALS

With institutional review board approval, we identified patients with endometrial cancer meeting American Brachytherapy Society criteria of high-risk features treated with adjuvant HDR between 2004 and 2010. HDR doses were 21Gy in 3 fractions delivered to either the full-length or partial-length vagina. Acute and late toxicities were evaluated using the Radiation Therapy Oncology Group scale and Radiation Therapy Oncology Group/European Organisation for Research and Treatment of Cancer grading, respectfully. Vaginal recurrences were assessed by physical examination and pap smears. Statistical analyses were performed using SPSS version 23 software.

RESULTS

Of 240 patients treated with HDR brachytherapy, 121 were treated with FLV brachytherapy, and 119, with PLV brachytherapy. The median follow-up was 9.5 years (range, 8-11 years) for FLV patients and 8.5 years (range, 7-10 years) for PLV patients; 0% of patients had vaginal recurrences, and 1.4% and 0.9% had proximal vaginal recurrences, respectively (P = .54). All patients treated with FLV brachytherapy developed grade 3 mucositis of the lower vagina/introitus (P < .0001) and had increased analgesics use compared with those treated with PLV brachytherapy (P < .0001). In total, 23% of patients treated with FLV brachytherapy developed grade 3 stenosis of the lower vagina/introitus, in contrast to 0% of patients treated with PLV brachytherapy (P < .0001).

CONCLUSIONS

PLV brachytherapy is as effective as FLV brachytherapy in reducing local recurrence and causes a significantly lower incidence of acute and late toxicities. The results of this study caution radiation oncologists regarding the careful use of FLV brachytherapy in patients with endometrial cancer and high-risk features.

Vaginal dilator use more than 9 months is a main prognostic factor for reducing G2‑late vaginal complications in 3D‑vaginal‑cuff brachytherapy (interventional radiotherapy)?

PURPOSE

Analyse the impact of different prognostic factors on G2-late vaginal complications after vaginal brachytherapy (VBT) ± external beam radiotherapy (EBRT) in postoperative endometrial cancer (PEC).

METHODS

One hundred and twenty-six PEC patients treated with VBT ± EBRT were retrospectively analysed considering age, body mass index, applicator diameter, clinical target volume (CTV), use of dilators, chemotherapy and EQD2_(α/β=3) at the most exposed 2 cm³ of the CTV as prognostic factors for vaginal complications. Late vaginal complications were evaluated using objective LENT-SOMA criteria.

STATISTICS

descriptive analysis, Chi-square, Fisher and Student tests were applied. Univariate and multivariate analyses were performed with the Baptista-Pike exact method and multiple logistic regression.

RESULTS

Mean age was 65 years (SD ± 10), and median follow-up was 66 months (8-104). 19/126 patients (15%) showed G2-late vaginal complications, and 107/126 (85%) G0-G1. Univariate analysis showed: CTV ≤ 9 cm³ (p = 0.036), use of dilators < 9 months (p = 0.015), and total ≥ 68 Gy EQD2 received by 2 cm³ of CTV (p = 0.039) were associated with G2-late vaginal toxicity. Multivariate analysis showed the use of dilators < 9 months as an independent prognostic factor for G2-late vaginal toxicity (p = 0.043, OR 8.59, CI 1.59-159.9).

CONCLUSION

The use of dilators < 9 months in VBT ± EBRT for PEC was an independent prognostic factor for G2-late vaginal toxicity. The use of vaginal dilators ≥ 9 months requires further analysis in studies evaluating late vaginal toxicity.

In Vivo Verification of Treatment Source Dwell Times in Brachytherapy of Postoperative Endometrial Carcinoma: A Feasibility Study

(1) Background: In brachytherapy, there are still many manual procedures that can cause adverse events which can be detected with in vivo dosimetry systems. Plastic scintillator dosimeters (PSD) have interesting properties to achieve this objective such as real-time reading, linearity, repeatability, and small size to fit inside brachytherapy catheters. The purpose of this study was to evaluate the performance of a PSD in postoperative endometrial brachytherapy in terms of source dwell time accuracy. (2) Methods: Measurements were carried out in a PMMA phantom to characterise the PSD. Patient measurements in 121 dwell positions were analysed to obtain the differences between planned and measured dwell times. (3) Results: The repeatability test showed a relative standard deviation below 1% for the measured dwell times. The relative standard deviation of the PSD sensitivity with accumulated absorbed dose was lower than 1.2%. The equipment operated linearly in total counts with respect to absorbed dose and also in count rate versus absorbed dose rate. The mean (standard deviation) of the absolute differences between planned and measured dwell times in patient treatments was 0.0 (0.2) seconds. (4) Conclusions: The PSD system is useful as a quality assurance tool for brachytherapy treatments.

Toxicity and Efficacy After Adjuvant Vaginal Brachytherapy Using 30 Gy in 6 Fractions for Stages I and II Endometrial Cancer

Purpose

This study aimed to evaluate outcomes and toxicity in patients with endometrial cancer per our institutional adjuvant vaginal cuff brachytherapy (VBT) fractionation scheme.

Methods and Materials

We identified women with International Federation of Gynecology and Oncology stages I and II endometrial cancer who underwent surgical staging and adjuvant high-dose-rate VBT without external beam radiation. All patients received 30 Gy in 6 fractions to the upper one-third of the vagina, prescribed to a depth of 5 mm and delivered twice weekly. Toxicities were prospectively elicited at each follow up, and rates of recurrence and survival were retrospectively assessed.

Results

We identified 247 eligible patients treated between 1992 and 2018 with a median follow up of 5.8 years (range, 0.1-24.7 years). Most patients had stage I disease (52% stage IA; 37% stage IB), and 11% of patients were stage II. Deep myometrial invasion was predictive of local recurrence (P = .002). The 5-year rates of local recurrence, regional recurrence, and distant metastases were 5%, 5%, and 7%, respectively. Five-year overall and disease-free survival were 91% and 83%, respectively. The most common grade 1 toxicities were acute fatigue (11% crude rate), urinary frequency (11%), chronic (>6 months) urinary frequency (13%), urinary incontinence (13%), and vaginal stenosis (21%). There were few grade 2 toxicities (all <5%) and no grade 3 to 5 toxicities.

Conclusions

The adjuvant VBT fractionation scheme of 30 Gy in 6 fractions results in low rates of toxicity, with no grade ≥3 adverse events, and local control rates comparable with those from other published series using different fractionation schemes.

Preliminary results of a vaginal constraint for reducing G2 late vaginal complications after postoperative brachytherapy in endometrial cancer: a prospective analysis

Purpose

To evaluate the preliminary results of the use of 68 Gy EQD2_{(α/β=3 Gy)} as a dose limit to the lowest dose in the most exposed 2 cm³ of the vagina in order to reduce G2 late vaginal problems in postoperative endometrial carcinoma (EC).

Methods

From November 2016 to October 2019, 69 postoperative EC patients receiving vaginal brachytherapy (VBT) ± external beam radiotherapy (EBRT) were prospectively analyzed. The median EBRT dose was 45 Gy (range: 44–50.4 Gy), 1.8−2 Gy/day, 5 fractions(Fr)/week. VBT was administered with the following schedule: 1Fr of 7 Gy after EBRT and 2 daily Fr × 7.5 Gy in exclusive VBT. The dose was prescribed at 0.5 cm from the applicator surface with an active length of 2.5 cm; 56 patients were treated with vaginal cylinders (49–3.5 cm, 6–3 cm, and 1–2.5 cm) and 13 with the colpostat technique. The overall VBT dose was adjusted to meet the vaginal restriction of < 68 Gy EQD2_{(α/β=3 Gy)} at 2 cm³. Late toxicity was prospectively assessed using RTOG scores for bladder and rectum, and the objective LENT-SOMA criteria for vagina.

Results

With a median follow-up of 31.0 months, no vaginal-cuff recurrences were found. Late toxicity: only 1G1(1.4%) rectal toxicity; 21G1(30.4%) and 3G2(4.3%) vaginal complications. Only one (1.4%) of 3 G2 manifested as vaginal shortening.

Conclusions

In postoperative EC patients treated with VBT, only one developed G2 vaginal stenosis with the use of 68 Gy EQD2_{(α/β=3 Gy)} as a dose constraint. These preliminary results seem to indicate the value of this dose limit for reducing G2 vaginal stenosis. Nonetheless, these findings should be confirmed in a larger number of patients with longer follow-up.

Vaginal cuff brachytherapy: do we need to treat to more than a two-centimeter active length?

Purpose

American Brachytherapy Society (ABS) guidelines recommend using a 3-5 cm active length (AL) when treating vaginal cuff (VC) in adjuvant setting of endometrial cancer (EC). The purpose of this study was to evaluate local control and toxicity, using an AL of 1 or 2 cm and immobilization with a traditional table-mounted (stand) or patient-mounted (suspenders) device.

Material and methods

Between 2005 and 2019, 247 patients with EC were treated with adjuvant high-dose-rate vaginal cuff (HDR-VC) brachytherapy with or without external beam radiation (EBRT). Treatment was prescribed to a 0.5 cm depth, with an AL of 1 or 2 cm, using stand or suspenders. VC boost after EBRT was typically administered with 2 fractions of 5.5 Gy, while VC brachytherapy alone was typically applied with 3 fractions of 7 Gy or 5 fractions of 5.5 Gy.

Results

The combination of suspender immobilization and an AL of 2 cm (n = 126, 51%) resulted in 5-year local control of 100%. An AL of 2 cm compared to 1 cm correlated with better local control (99.1% vs. 88.5%, p = 0.0479). Regarding immobilization, suspenders correlated with improved local control compared to stand (100% vs. 86.7%, p = 0.0038). Immobilization technique was significantly correlated with AL (p < 0.0001). Only 5 (2.0%) patients experienced grade ≥ 3 toxicity, all of whom received EBRT.

Conclusions

In the present series, an AL of 2 cm provided excellent local control, while 1 cm was inadequate. Suspender immobilization was a practical alternative to stand immobilization in HDR brachytherapy of the vaginal cuff.

Consensus and recommendations on vaginal-cuff Brachytherapy of the Spanish Brachytherapy Groups of SEOR and SEFM

PURPOSE/OBJECTIVE(S)

On October 5, 2018, a meeting of the Spanish Society of Radiation Oncology (SEOR) Brachytherapy Group was held, in collaboration with the Spanish Society of Medical Physics (SEFM), with the aim of preparing a consensus document on postoperative vaginal-cuff brachytherapy (VCBT).

MATERIALS/METHODS

A survey including 42 questions was sent to Spanish Radiation Oncology Centres before the meeting. The survey items included: experience in VCBT, technique indications, previous patient preparation, applicator type, implant procedure, computerized tomography (CT) simulation, definition of target volumes and organs at risk (OAR), dose prescription, fractionation, treatment planning, dosimetric parameters and constraints to OAR. Thirty-three centres answered the survey. Statistical analysis of the survey considered that there was consensus when there was ≥ 85% of agreement related to a survey item, otherwise an item with < 85% of agreement would be discussed during the meeting to reach consensus.

RESULTS

The results of the survey are reported here. The mean number of patients treated per centre in 2017 was 52 ± 41 (range 7-175), and the mean number of procedures per centre was 175 ± 150 (range 24-701).There was consensus on: the indications, applicator type, the OAR to be considered, the prescription point, standardisation and dosimetric quality parameters. There was no consensus on: patient preparation for the implant, the need for performing CT simulation and the frequency, the length of the vagina to be treated, if CTV should be delimited, the definition of the clinical target volume, fractionation, overall EQD2, active source length, separation between dwelling stepping source positions, if considering the uniformity/maximum values for dwelling stepping sources, the optimization mode, and the limiting doses to the OAR. After presenting the results of the survey, the consensus meeting discussion focused on the issues for which there was no consensus.

CONCLUSION

A consensus document on postoperative VCBT of the Spanish Brachytherapy Groups of SEOR-SEFM was elaborated.

EQD2 Analyses of Vaginal Complications in Exclusive Brachytherapy for Postoperative Endometrial Carcinoma

Simple Summary

Vaginal complications in exclusive vaginal-cuff brachytherapy (EVCBT) have not been analyzed in terms of the dose received by a vaginal volume of 2 cm³. The aim of this work was to analyze the vaginal dose and complications in EVCBT. In the present analysis, we found that all the patients receiving < 68Gy equivalent dose 2Gy/day at 2 cm³ of the most exposed area to the dose of the vagina only developed G0–G1 and 1G2 without vaginal stenosis complications and without relapses. This dose limit could eliminate G2 vaginal stenosis and is the hypothesis of a new analysis in our center.

Abstract

Background: To evaluate whether EQD2_{(α/β = 3Gy)} at 2 cm³ of the most exposed area of the vagina is related to late vaginal toxicity in postoperative endometrial cancer (PEC) patients (p) treated with exclusive brachytherapy (BT). Methods: From 2014 to 2017, 43p were included in this study. BT was administered: 3-fractions of 6Gy in 37p and 2-fractions of 7.5Gy in 6p. The dose was prescribed at a depth of 5 mm from the applicator surface with dose-point optimization based on distance. The active treatment length was 2.5 cm. CTV-D90 and the dose to the most exposed 2 cm³ of the vagina was calculated for each patient. Late toxicity of the bladder and rectum was assessed using Radiation Therapy Oncology Group (RTOG) criteria, and vaginal toxicity by objective Late Effects Normal Tissue Task Force (LENT)-Subjective, Objective, Management, Analytic (SOMA) (LENT-SOMA) criteria. Statistics: frequency tables, mean, median, range, standard deviation, and box plot. Results: The median follow-up was 51 months (12–68). 20 p (46.5%) and 2 p (4.7%) developed G1 and G2 vaginal complications, respectively. Only 1/2 p-G2 receiving EQD2_{(α/β = 3Gy)} at 2 cm³ >68Gy presented vaginal shortening and 18/20 p-G1 received doses < 68Gy. Conclusions: PECp receiving exclusive brachytherapy with doses < 68Gy EQD2_{(α/β = 3Gy)} at 2 cm² of the vagina presented only G0–G1 vaginal toxicity, except for one with bleeding telangiectasias. Larger prospective studies are necessary to confirm the present results.

Postoperative endometrial carcinoma treated with external beam irradiation plus vaginal-cuff brachytherapy. Is there a dose relationship with G2 vaginal complications?

AIM

To analyse the possible relationship between the EQD2(α/β=3Gy) at 2 cm3 of the vagina and late toxicity in vaginal-cuff-brachytherapy (VBT) after external-beam-irradiation (EBRT) for postoperative endometrial carcinoma (EC).

MATERIALS AND METHODS

From 2014 to 2016, 62 postoperative EC patients were treated with EBRT + VBT. The median EBRT dose was 45 Gy (44 Gy-50.4 Gy). VBT involved a single 7 Gy dose. Toxicity was prospectively evaluated using the RTOG score for the rectum and bladder and the objective LENT-SOMA criteria for the vagina. EQD2(α/β = 3Gy) at 2 cm3 of the most exposed part of the vagina was calculated by the sum of the EBRT + VBT dose. Statistics: Boxplot, Student's t and Chi-square tests and ROC curves.

RESULTS

Mean follow-up: 39.2 months (15-68). Late toxicity: bladder:0 patient; rectum:2 patients-G1; Vagina: 26 patients-17G1, 9G2; median EQD2(α/β=3Gy) at 2 cm3 in G0-G1 patients was 70.4 Gy(SD2.36), being 72.5 Gy(SD2.94) for G2p. The boxplot suggested a cut-point identifying the absence of G2: 100 % of G2p received >68 Gy, ROC curves showed an area under the curve of 0.72 (sensitivity of 1 and specificity of 0.15).

CONCLUSIONS

Doses >68 Gy EQD2(α/β=3Gy) at 2 cm3 to the most exposed area of the vagina were associated with late G2 vaginal toxicity in postoperative EC patients treated with EBRT + VBT suggesting a very good dose limit to eliminate the risk of G2 late toxicity. The specificity obtained indicates the need for prospective analyses.

Is one brachytherapy fraction of 7 Gy similar to more fractions after external beam irradiation in postoperative endometrial carcinoma?

PURPOSE

To determine whether brachytherapy with a single hypofractionated dose of 7 Gy provides the similar vaginal-cuff relapses and safety profile in terms of complications compared to schedules of 2 or 3 fractions of lower doses in patients treated previously with external beam irradiation in postoperative endometrial carcinoma.

METHODS/MATERIAL

From June 2003 to December 2016, 325 patients were treated with 3 different schedules of high-dose-rate brachytherapy after external beam irradiation for postoperative endometrial carcinoma. The patients were divided into 3 groups: Group-1: 125 patients were treated with 3 fractions of 4-6 Gy per fraction (3 fractions/week) between 2003 and 2008; Group-2: 93 patients were treated with 2 consecutive daily fractions of 5-6 Gy between 2008 and 2011; Group-3: 107 patients received a single fraction of 7 Gy between 2011 and 2016. Bladder and rectum complications were assessed using RTOG scores and with the objective scores of LENT-SOMA for the vagina.

STATISTICS

the chi-square test.

RESULTS

The mean follow-up of Groups 1, 2 and 3 was 95, 67 and 51 months, respectively. Three patients in Group-1, 2 in Group-2, 1 in Group-3 developed vaginal-cuff relapse (p = 0.68). No differences were found in late toxicity among the three groups.

CONCLUSIONS

One single dose of 7 Gy is safe and effective and may be the best treatment schedule with a similar incidence of vaginal-cuff relapses, complications and patient comfort with less hospital attendance.

Economic impact of decreasing the fraction number in vaginal cuff brachytherapy: A direct cost analysis

PURPOSE

The purpose of this study was to analyze the direct economic impact of two vaginal cuff brachytherapy (VBT) schedules in postoperative endometrial carcinoma (PEC) with similar vaginal control and toxicity results.

MATERIALS AND METHODS

From 2006 to 2015, 397 PEC patients (p) were treated with VBT: mean 40p/year, 67.5% received external beam radiotherapy (EBRT)+VBT and 32.5% exclusive VBT. Schedule 1: 3 fractions (Fr) after EBRT and 6Fr (4-6 Gy/Fr) in exclusive VBT. Schedule 2: 7Gy × 1Fr + EBRT and 6Gy × 3Fr in exclusive VBT. Differential cost analysis of the two schedules was retrospectively performed. The direct costs in each schedule were (1) Personnel: radiotherapy technicians, nurses, radiation oncologists, medical physicists, administrative personnel, orderlies; time dedicated by each professional during CT planning acquisitions and delineation of vagina/organs at risk, dosimetric study and evaluation, autoradiography, procedure reporting time during/after treatment, removal of bladder/rectal tubes and applicators, material cleaning and transportation for sterilization; (2) Health care material (gels, gauzes, gloves, etc); (3) Equipment (time equipment used). The differential between the two schedules was estimated. Indirect costs and evaluation of quality of life-adjusted costs were not considered.

RESULTS

The overall reduction in the number of Fr per year in Schedule 2 was 93. Cost savings included treatment time per year: 4,185 min (70 h); personnel: 221€ ($246)/p in EBRT + VBT and 331€ ($368)/p in exclusive VBT; and health care material and equipment: 40€ ($44.5)/p in EBRT + VBT and 90€ ($100.2)/p in exclusive VBT. The overall savings per patient was 261€ ($295) in combined treatment and 421€ ($475.7) in exclusive VBT. The total savings per year with Schedule 2 in 40p was 12,503€ ($13,915.8).

CONCLUSIONS

A 41% reduction in the fractions number in VBT for PEC allowed economic savings of 261€ ($290.5)/p in combined treatment and 421€ ($475.7)/p in exclusive VBT. Other benefits include patient comfort and fewer treatment visits.