Implementation of image-guided brachytherapy as part of non-surgical treatment in inoperable endometrial cancer patients

Clinical outcomes analysis of image-guided brachytherapy as definitive treatment for inoperable endometrial cancer

OBJECTIVES

This study evaluates the efficacy and toxicity of image-guided brachytherapy combined with or without external beam radiotherapy (IGBT ± EBRT) as definitive treatment for patients with inoperable endometrial cancer (IOEC), in addition to establishing a risk classification to predict prognosis.

METHODS

Fifty-one IOEC patients who underwent IGBT ± EBRT at Peking Union Medical College Hospital from January 2012 to December 2021 were retrospectively analyzed, of which 42 patients (82.4%) were treated with IGBT + EBRT and 9 patients (17.6%) with IGBT alone. Establishing risk classification based on FIGO 2009 staging and biopsy pathology, stage III/IV, non-endometrioid, or Grade 3 endometrioid cancer were included in the high-risk group (n = 25), and stage I/II with Grade 1-2 endometrioid cancer was included in the low-risk group (n = 26).

RESULTS

The median follow-up time was 58.0 months (IQR, 37.0-69.0). Clinical complete remission (CR) was achieved in 92.2% of patients after radiotherapy (n = 47). The cumulative incidences of locoregional and distant failure were 19.6% (n = 10) and 7.8% (n = 4), respectively. A total of 20 patients died (39.2%), including 10 cancer-related deaths (19.6%) and 10 comorbidity-related deaths (19.6%). The 5-year locoregional control (LRC), time to progression (TTP), overall survival (OS), and cancer-specific survival (CSS) were 76.9%, 71.2%, 59.4%, and 77.0%, respectively. No Grade 3 or above acute or late toxicities were reported. In univariate analysis, LRC, TTP, and CSS were significantly higher in the low-risk group than in the high-risk group (P < 0.05). After adjusting for age, number of comorbidities, radiotherapy modality, and chemotherapy, the low-risk group was still significantly better than the high-risk group in terms of LRC (HR = 6.10, 95% CI: 1.18-31.45, P = 0.031), TTP (HR = 8.07, 95% CI: 1.64-39.68, P = 0.010) and CSS (HR = 6.29, 95% CI: 1.19-33.10, P = 0.030).

CONCLUSIONS

IGBT ± EBRT is safe and effective as definitive treatment for IOEC patients, achieving satisfactory locoregional control, favorable survival outcomes, and low toxicity. Risk classification based on FIGO 2009 staging and biopsy pathology is an independent prognostic factor for LRC, TTP, and CSS.

National Cancer Database analysis of radiation therapy consolidation modality and dose for inoperable endometrial cancer

OBJECTIVE

We utilized the National Cancer Database (NCDB) to evaluate trends and assess outcomes in radiation therapy (RT) boost modality and total dose among medically inoperable endometrial cancer (EC) patients with locoregional disease.

METHODS

Patients with International Federation of Gynecology and Obstetrics (FIGO) stage I - IIIC2 inoperable EC treated with RT ± chemotherapy were analyzed. Practice patterns compared external beam RT (EBRT) versus high-dose-rate brachytherapy (BT) boost and total RT dose (palliative: ≤3000 cGy, definitive low dose [DLD]: 4500 - 6249 cGy, definitive high dose [DHD]: ≥6250 cGy) over time. Kaplan-Meier method evaluated overall survival (OS) and Cox proportional hazard modeling assessed variables associated with OS.

RESULTS

NCDB included 1755 total cases, of which 1209 received a radiotherapy boost. From 2004 to 2019, boost modality rates differed with increasing utilization of BT consolidation and a decreasing rate of palliation. Predictors of a palliative dose were stage III disease, Black race, N2 disease, and poorly or undifferentiated grade. Multivariable analysis found BT boost was associated with lower mortality compared to EBRT (HR: 0.81, CI: 0.68-0.97; p = 0.019). Mortality rates were higher for palliation versus DHD. Additional factors associated with inferior survival were increasing age, worse Charlson-Deyo score, higher T stage, higher N stage, and moderately, poorly, or undifferentiated grade.

CONCLUSIONS

Utilization of BT boost for locoregionally confined, medically inoperable EC has increased since 2004. Brachytherapy consolidation remains an effective RT modality for medically inoperable EC, associated with lower mortality compared to EBRT consolidation.

Stages I-III Inoperable Endometrial Carcinoma: A Retrospective Analysis by the Gynaecological Cancer GEC-ESTRO Working Group of Patients Treated with External Beam Irradiation and 3D-Image Guided Brachytherapy

BACKGROUND/PURPOSE

Analyse the outcomes of stages I-III inoperable endometrial cancer (IEC) patients treated with external-beam-irradiation (EBRT) and 3D-image-guided-brachytherapy (IGBT).

MATERIAL AND METHODS

Medical records of IEC patients receiving EBRT + IGBT in eight European and one Canadian centres (2004-2019) were examined, including: pelvic ± para-aortic EBRT and lymph node boost; anaesthetic procedure, applicators, BT-planning imaging, clinical target volume (CTV), brachytherapy schedule, and EQD2 to the CTV(α/β=4.5Gy) and D2 cm3(α/β=3Gy) for organs at risk. Complications are evaluated using CTCAEv4 scores. The 2- and 5-year survival probability according to stages was estimated (cancer-specific survival (CSS), disease-free survival (DFS), local relapse-free survival (LRFS), loco-regional relapse-free survival (LRRFS), and distant metastasis-free survival (DMFS)).

STATISTICS

descriptive analysis and the Kaplan-Meier method.

RESULTS

103 patients (stages: I-44, II-14, III-44) were included. Median follow-up: 28 months (7-170). All patients received pelvic ± para-aortic EBRT. Median D90-EQD2(α/β=4.5) to the CTV:73.3 Gy (44.6-132.7), 69.9 Gy (44.7-87.9 and 75.2 Gy (55.1-97) in stages I, II, and III, respectively. Thirty patients presented relapse (stages: 10-I, 3-II, 17-III): 24 uterine (stages: 7-I, 3-II, 14-III), 15 nodal (stages: 4-I, 1-II, 10-III), and 23 distant (stages: 6-I, 2-II, 15-III). Five year CSS was 71.2% (stages: 82%-I-II and 56%-III) and DFS, LRFS, LRRFS, and DMFS were 55.5%, 59%, 72%, and 67.2%, respectively. Late G3-G4 complications (crude): 1.3% small bowel, 2.5% rectum, and 5% bladder.

CONCLUSION

In stages I-III of the IEC, EBRT + IGBT offer good 2- and 5-year CSS of 88.7% and 71.2%, respectively, with the best outcomes in stages I-II. Prospective studies are needed to determine how better outcomes can be achieved.

Recommandations pour la pratique clinique Nice/Saint-Paul-de-Vence 2022–2023 : prise en charge du cancer de l'endomètre localisé

Recommendations for clinical practice, Nice/Saint-Paul-de-Vence 2022-2023: Management of localized endometrial cancer Endometrial cancer is the most frequent gynecological cancers in industrialized countries and its incidence increases. The newmolecularclassification allows determination of the risk of recurrence and helps orienting therapeutic management. Surgery remains the cornerstone of treatment. Minimally invasive approach must be preferred for stages I and II. Surgery includes hysterectomy with bilateral adnexectomy, sentinel lymph node biopsy even in high risk diseases and omentectomy for non-endometrioid tumors (except in case of clear cells tumors). Fertility preservation can be proposed in low grade, stage I tumors without myometrial involvement. In stage III/IV disease, lymph node debulking without totallymphadenectomy is indicated. In case of peritoneal carcinomatosis, first-line cytoreductive surgery is recommended if complete resection can be achieved. Adjuvant therapy is not recommended in low risk tumors. In intermediate risk tumors, curietherapy is indicated. In tumors with high-intermediate risk, curietherapy and external radiotherapy are indicated according to prognostic factors (stage II, lymphovascular invasion); adjuvant chemotherapy can be considered on a case-by-case basis. In high risk tumors, chemotherapy and external radiotherapy are recommended using a concomitant or sequential approach.

What is appropriate target delineation for MRI-based brachytherapy for medically inoperable endometrial cancer?

PURPOSE

For medically inoperable endometrial cancer (MIEC), the volumetric target of image-guided brachytherapy (IGBT) techniques is not well established. We propose a high-risk CTV (HRCTV) concept and report associated rates of local control and toxicity.

METHODS AND MATERIALS

For all MIEC patients receiving definitive external beam radiotherapy (EBRT) followed by MRI-based IGBT at a single institution, BT dose was prescribed to HRCTV defined as GTV plus endometrial cavity with a planning goal of a summed EQD2 D90 of ≥85 Gy. Freedom from local progression (FFLP) and overall survival (OS) were estimated via Kaplan Meier method.

RESULTS

Thirty two MIEC patients received EBRT followed by MRI-based IGBT between December 2015 and August 2020. Median follow up was 19.8 months. A total of 75% of patients had FIGO stage I/II disease, 56% endometrioid histology, and 50% grade 3 disease. OS was 73.6% (95% CI 57.8%-89.3%) at 12 months and 65.8% (95% CI 48.4%-83.2%) at 24 months. FFLP was 93.8% (95% CI 85.3%-100%) at 12 months and 88.8% (95% CI 86.6%-91.0%) at 24 months. 23 (72%) patients experienced no RT-related toxicity, while 2 of 32 patients (6%) experienced late grade 3+ toxicities (grade 3 refractory vomiting; grade 5 GI bleed secondary to RT-induced proctitis).

CONCLUSIONS

Patients with MIEC receiving definitive EBRT followed by MRI-based IGBT prescribed to the MRI-defined HRCTV demonstrated favorable long-term local control with an acceptable toxicity profile.

Image-guided brachytherapy following external-beam radiation therapy for patients with inoperable endometrial cancer

OBJECTIVE

To investigate the outcomes of definitive external-beam radiation therapy (EBRT) plus image-guided brachytherapy (IGBT) in patients with endometrial cancer (EC) unsuitable for surgery.

METHODS

A total of 50 patients with inoperable EC were included. The patients received EBRT in a median dose of 45 Gy to the pelvis over 5 weeks. Thereafter, the patients received brachytherapy using tandem and ovoid applicators. High-risk clinical target volume (HR-CTV) and gross tumor volume in brachytherapy (GTVp) were defined by the assistance of patients' pre-IGBT magnetic resonance imaging.

RESULTS

The medical records of the 50 patients were analyzed. The main causes of inoperability were anesthesia contraindications, namely medical comorbidities and obesity. The median cumulative D90s (the minimum dose delivered to 90% of the volume) in EQD2 (equivalent dose in 2-Gy fractions) to the HR-CTV and GTVp were 72.9 Gy10 (range, 64.9 to 80.3) and 166.2 Gy10 (range, 123.0 to 189.8), respectively. Over a median follow-up period of 27 months, 8 of the patients died of cancer. The 2-year overall and cancer-specific survival rates were 75% and 83%, respectively. The cumulative incidences of pelvic and distant failure were 4% (n = 2) and 16% (n = 8), respectively. Gastrointestinal complications of grade 2 or above were noted in 2 patients (4%), and a grade 2 genitourinary complication was noted in one.

CONCLUSIONS

For patients with inoperable EC, EBRT followed by IGBT is an effective approach for achieving high local control without a high risk of complications.

Targeting the GTV in medically inoperable endometrial cancer using brachytherapy

PURPOSE

We aimed to determine the relationship between gross tumor volume (GTV) dose and tumor control in women with medically inoperable endometrial cancer, and to demonstrate the feasibility of targeting a GTV-focused volume using imaged-guided brachytherapy.

METHODS AND MATERIALS

An endometrial cancer database was used to identify patients. Treatment plans were reviewed to determine doses to GTV, clinical target volume (CTV), and OARs. Uterine recurrence-free survival was evaluated as a function of CTV and GTV doses. Brachytherapy was replanned with a goal of GTV D98 EQD₂ ≥ 80 Gy, without regard for coverage of the uninvolved uterus and while respecting OAR dose constraints.

RESULTS

Fifty-four patients were identified. In the delivered plans, GTV D90 EQD₂ ≥ 80 Gy was achieved in 36 (81.8%) patients. Uterine recurrence-free survival was 100% in patients with GTV D90 EQD₂ ≥ 80 Gy and 66.7% in patients with EQD₂ < 80 Gy (p = 0.001). On GTV-only replans, GTV D98 EQD₂ ≥ 80 Gy was achieved in 39 (88.6%) patients. Mean D_2cc was lower for bladder (47.1 Gy vs. 73.0 Gy, p < 0.001), and sigmoid (47.0 Gy vs. 58.0 Gy, p = 0.007) on GTV-only replans compared to delivered plans. Bladder D_2cc was ≥ 80 Gy in 11 (25.0%) delivered plans and four (9.1%) GTV-only replans (p = 0.043). Sigmoid D_2cc was ≥ 65 Gy in 20 (45.4%) delivered plans and 10 (22.7%) GTV-only replans (p = 0.021).

CONCLUSIONS

OAR dose constraints should be prioritized over CTV coverage if GTV coverage is sufficient. Prospective evaluation of image-guided brachytherapy to a reduced, GTV-focused volume is warranted.

Investigation the effect of a magnetic field on the dose distribution of I-125, Ir-192, Yb-169, and Co-60 brachytherapy sources by Monte Carlo simulation

Magnetic resonance imaging (MRI) during brachytherapy may alter the dose distribution of radioactive sources implanted in the tumor. This study investigates the impact of a magnetic field of 1.5 T, 3 T, and 7 T strengths on the dose distribution of high dose rate Co-60, Ir-192, and Yb-169, and low dose rate I-125 sources, using Geant4 Monte Carlo toolkit. After validating the simulation results by calculating the AAPM-TG43 dosimetric parameters, seven sources of each radioisotope were simulated in a water phantom, and their dose distributions were compared under the influence of a magnetic field. The simulation results indicate that using Co-60 brachytherapy under the MRI guidance is not recommended. Furthermore, the impact of a magnetic field of up to 7 T strength on the dose distribution of Ir-192, Yb-169, and I-125 sources is negligible, provided that there is no air pocket near brachytherapy sources.

Radiation therapy in the definitive management of medically inoperable endometrial cancer

The incidence of endometrial cancer continues to increase worldwide with growing life expectancy and rates of obesity. While endometrial cancer is primarily a surgical disease managed with hysterectomy, a small proportion of patients are deemed to be poor surgical candidates due to their co-morbidities. These medically inoperable patients should be considered for curative treatment with definitive radiation therapy, and brachytherapy is an integral component of their care. Referral to a high-volume center early on in the care of potentially inoperable patients is crucial to optimize their management. These patients should be evaluated by a high-risk surgical and anesthesia team to confirm their medical inoperability. For inoperable patients, use of image-guided brachytherapy is encouraged. Brachytherapy applicator selection is determined based on a patient’s anatomy, uterine size, and extent of tumor. Advances in anatomic and functional imaging including multiparametric magnetic resonance imaging (MRI) have improved clinical staging of these patients and have also allowed for the delivery of three-dimensional image-guided brachytherapy with improved accuracy. With recent consensus guidelines to guide local computed tomography and/or MRI volume-based delineation of targets and organs-at-risk, local outcomes have improved and treatments are delivered with less acute and late morbidity. Ongoing trials are looking at novel systemic agents, such as immunotherapy, to induce a systemic anti-tumor immune response and improve outcomes in these patients.

Radiotherapy for endometrial cancer

The first intent upfront treatment of endometrial cancer is surgery. External radiotherapy and brachytherapy; however, are important tools in adjuvant setting, according to histopathological risk factors for locoregional recurrence or in the event of an inoperable tumor. We present the update of the recommendations of the French society of oncological radiotherapy on the indications and technical methods of performing radiotherapy and brachytherapy for endometrial cancer.

High Dose Rate Brachytherapy for Inoperable Endometrial Cancer: a Case Series and Systematic Review of the Literature

Endometrial cancer is a common gynaecological cancer, is typically early stage and treated with surgery. For patients where surgery is difficult or dangerous, definitive radiation therapy is the next best option. This study included a single institution case series (step 1) and a systematic review of the literature (step 2). In step 1, all endometrial cancer cases that were treated with definitive image-guided brachytherapy at a single institution from 2008 to 2020 were retrospectively analysed. In step 2, a systematic review of Medline (PubMed) from 1975 to 2020 was carried out using the key words around endometrial cancer and brachytherapy, followed by a narrative synthesis. In total, in step 1, 31 cases were included in this study, stages I-IV, with 96.7% receiving external beam radiation. All patients received three fractions of 7.5 Gy or five fractions of 6 Gy high dose rate brachytherapy, with a median EQD2 of 75.55 (40-84.3). The 2-year Kaplan-Meier (KM) local control was 83.1% and the 2-year KM overall survival was 77.4%. There was no late toxicity ≥grade 3. In step 2, 19 articles were included in the final analysis, with between six and 280 patients. The local control ranged from 70 to 100%, with low toxicity. Definitive radiation therapy with image-guided brachytherapy seems to have good local control with low toxicity for patients who are poor surgical candidates.

Exclusive 3D-brachytherapy as a good option for stage-I inoperable endometrial cancer: a retrospective analysis in the gynaecological cancer GEC-ESTRO Working Group

PURPOSE

Analyse outcomes of stage-I inoperable endometrial cancer (EC) patients from seven European centres treated with 3D-image-guided brachytherapy (IGBT) alone.

MATERIALS AND METHODS

From 2004 to 2018, 62 patients (41 stage-IA and 21 IB) were retrospectively studied, analysing anaesthetic procedure, applicator type, BT-planning imaging, clinical target volume (CTV), BT schedule, overall daily-dose equivalent to 2 Gy (EQD2_{(α/β=4.5 or 3)}) to the CTV_(α/β=4.5) and D2 cm³_(α/β=3) for organs at risk. Complications were evaluated using CTCAEv4 scores. The 2 and 5 year survival was calculated [cancer-specific survival (CSS), disease-free survival (DFS), local relapse-free survival (LRFS), loco-regional relapse-free survival (LRRFS) and distant metastasis-free survival (DMFS)]. Descriptive analysis and the Kaplan-Meier method were used for survival analysis.

RESULTS

Mean follow-up: 32.8 months (SD 33.7). Spinal anaesthesia (38/62) followed by none (16/62) were the most common. Y-shaped Rotte applicators were used in 74% of patients. High-dose rate brachytherapy was administered in 89%. Median D90 to the CTV was 58.9 Gy (8.66-144 Gy). Eight patients presented relapse: four uterine, four nodal and four distant. The 2 and 5 year CSS was 93.3 and 80.5%, DFS 84.8 and 80.5%, LRFS was 93.1 and 88.7%, LRRFS was 91 and 91% and DMFS was 90.2 and 90.2%, respectively, CSS was better in stage-IA vs. IB (p = 0.043). Late vaginal and bladder G3-complication rates were 2.1%, respectively.

CONCLUSION

Inoperable EC patients can be safely treated by BT with 2 and 5 year CSS of 93 and 80.5%, respectively, with even better results for IA cases. Prospective studies on 3D-IGBT are necessary to better analyse EC patient outcomes based on dose and treated volumes.

Toxicity and outcomes associated with high-dose rate brachytherapy for medically inoperable endometrial cancer

PURPOSE

To evaluate toxicity in inoperable endometrial cancer (EC) treated with definitive radiation therapy (RT).

MATERIALS AND METHODS

Patients treated with definitive RT for EC were retrospectively reviewed. EQD2 values were calculated for bladder, rectum, and sigmoid. Acute and late toxicities were retrospectively graded. Descriptive statistical analysis was performed.

RESULTS

Fifty-one patients were included. The majority of patients had endometrioid histology (N = 46, 90.2%) and Grade 1 disease (N = 32, 62.75%). Thirty-seven patients (72.5%) were treated with image-guided BT (IGBT) and 14 (27.5%) with two-dimensional BT. Forty patients (78.4%) received EBRT + BT and 11 (21.57%) received BT alone. No grade 2 (G2) or higher toxicities were reported with BT alone. G2 or higher acute toxicities with EBRT + BT were G2 proctitis (N = 2, 5.0%) and G3 proctitis (N = 1, 2.5%). Late toxicities included G3 vaginal stenosis (N = 1, 2.5%), proctitis (N = 1, 2.5%), enteritis (N = 1, 2.5%), and one G4 gastrointestinal bleed. One- and 2-year local control were 100% with BT alone and 93% and 89%, respectively, with EBRT + BT. One- and 2-year locoregional control were 100% with BT and 97% and 93%, respectively, with EBRT + BT. Recurrence-free survival was 89% at 1 and 2 years with BT alone compared to 87% and 80% with EBRT + BT. One- and 2-year overall survival were 88% and 72% with BT alone compared to 94% and 84% with EBRT + BT. There were no statistically significant differences in cancer control between the two groups.

CONCLUSIONS

Women with inoperable EC treated with definitive RT have low toxicity rates and durable local control.

Practical brachytherapy solutions to an age-old quandary

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Age should not be a limiting factor for brachytherapy in patients with localised cancer or for palliation in metastatic disease.

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In tumour streams where brachytherapy forms part of the curative management, it should not be omitted in elderly patients who are medically fit for treatment.

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Treatment decisions should factor in patient preferences, the relative merits of different therapeutic approaches and maintaining minimal impact on quality of life.

Cancer is predominantly a disease of the elderly and as population life expectancy increases, so will the incidence of malignant disease. Elderly patients often have other comorbidities and social complexities, increasing the support required to safely deliver all treatment modalities. Brachytherapy is a relatively simple technique by which radiation therapy can be delivered. It offers dosimetric advantages through a highly conformal dose distribution thereby limiting radiation exposure to normal tissues reducing toxicity. Requiring fewer hospital visits, it also offers practical and logistical advantages to the elderly population and in many cases can be performed without the need for general anaesthesia. In tumour streams where brachytherapy forms part of the curative management, it should not be omitted in elderly patients who are medically fit for treatment. In the palliative setting, brachytherapy often offers an excellent means for achieving either local tumour and/or symptom control and should be actively considered in the therapeutic armamentarium of the oncologist in this context.

Evaluation of Uterine Brachytherapy as Primary Treatment Option for Elderly Patients with Medically Inoperable Endometrial Cancer-A Single-Center Experience and Review of the Literature

We aimed to gain more evidence regarding the feasibility, toxicity, and oncological outcome of primary brachytherapy in patients with medically inoperable endometrial cancer. Thirteen patients receiving primary brachytherapy ± external beam radiotherapy (EBRT) for endometrial cancer due to medical inoperability were identified. The Kaplan-Meier method was used to estimate overall survival (OS), progression-free survival (PFS), and local failure-free survival (LFFS). Univariate outcome analyses were performed using the log-rank test. Peri-interventional complications, acute and chronic toxicities were evaluated. Additionally, we performed a Pubmed search and review of the literature of the last 10 years. Mean age at time of diagnosis was 73.9 years (60.4-87.1 years). Eleven patients were staged FIGO IA/B and one patient each with FIGO IIIA and IIIC. Kaplan-Meier-estimated 2-/5-year LFFS were 76.2%/56.4%, respectively. High grading correlated with a worse LFFS (p = 0.069). Kaplan-Meier-estimated 2-/5-year PFS were 76.9%/53.8% and 2-/5-year-OS were 76.9%/69.2%, respectively. No acute toxicities > grade II and only two late toxicities grade II/III occurred. We observed three peri-interventional complications. The available evidence suggests high rates of local control after definitive brachytherapy for inoperable endometrial cancer with a favorable toxicity profile. Definitive brachytherapy +/- EBRT should be considered as the preferred approach for this patient group.