Radiation Therapy for Endometrial Cancer: An American Society for Radiation Oncology Clinical Practice Guideline

Preliminary results of adjuvant image-guided vaginal brachytherapy alone for early stage endometrial carcinoma

Objective

This retrospective study evaluated the preliminary outcomes of image-guided vaginal brachytherapy (IG-VBT) in the adjuvant treatment of high intermediate risk endometrial cancer.

Materials and Methods

Data were collected from 48 patients who underwent adjuvant IG-VBT between 2019 and 2022 at the Division of Radiation Oncology, Department of Radiology, Faculty of Medicine, Chiang Mai University. The vaginal cuff clinical target volume (CTV-VC) is composed of a 4-mm-thick band around vaginal cylinder at the upper 3 cm of the vaginal cuff. A total dose of 21 Gy in three fractions was delivered to the CTV-VC, and the dose to the bladder and rectum were evaluated. Treatment details, patient characteristics, and outcomes were analyzed. Descriptive statistics were used for analysis, and Kaplan-Meier method was employed for survival analysis.

Results

The mean age was 62 years, with mainly endometrioid carcinoma pathology (96 %). All patients were at stage I, with 87.5 % receiving complete surgical staging. Mean total treatment time was 10 days with mean D90 of CTV-VC was 29.7 Gy, and D2cc of bladder, rectum, and sigmoid were 24.6 Gy, 21.0 Gy, and 7.7 Gy, respectively. At a median follow-up of 37 months, 3-year local control, disease-free survival, and overall survival rates were 100 %, 100 %, and 97.9 %. respectively. Two patients (4.2 %) experienced grade 1-2 gastrointestinal toxicity, while no genitourinary toxicity or serious adverse events were observed.

Conclusions

The preliminary results of IG-VBT in endometrial cancer demonstrated favorable outcomes in terms of vaginal control and toxicity. Further studies with larger cohorts and longer follow-up durations are warranted.

Prognostic Effect of Mismatch Repair Status in Early-Stage Endometrial Cancer Treated With Adjuvant Radiation: A Multi-institutional Analysis

PURPOSE

The aim of this work was to report the effect of mismatch repair (MMR) status on outcomes of patients with stage I-II endometrioid endometrial adenocarcinoma (EEC) who receive adjuvant radiation therapy.

METHODS AND MATERIALS

This is a multi-institutional retrospective cohort study across 11 institutions in North America. Patients with known MMR status and stage I-II EEC status postsurgical staging were included. Overall survival (OS) and recurrence-free survival (RFS) rates were estimated via the Kaplan-Meier method. Univariable and multivariable analyses were performed via Cox proportional hazard models for RFS and OS. Statistical analyses were conducted using SPSS version 27.

RESULTS

In total, 744 patients with a median age at diagnosis of 65 years (IQR, 58-71) were included. Most patients were White (69.4%) and had Federation of Obstetrics and Gynecology 2009 stage I (84%) and Federation of Obstetrics and Gynecology grade 1 to 2 (73%). MMR deficiency was reported in 234 patients (31.5%), whereas 510 patients (68.5%) had preserved MMR. External beam radiation therapy with or without vaginal brachytherapy was delivered to 186 patients (25%), whereas 558 patients (75%) received vaginal brachytherapy alone. At a median follow-up of 43.5 months, the estimated crude OS and RFS rates for the entire cohort were 92.5% and 84%, respectively. MMR status was significantly correlated with RFS. RFS was inferior for MMR deficiency compared with preserved MMR (74.3% vs 88.6%, P < .001). However, no difference in OS was seen (90.8% vs 93.2%, P = .5). On multivariable analysis, MMR deficiency status was associated with worse RFS (hazard ratio, 1.86; P = .001) but not OS.

CONCLUSIONS

MMR status was independently associated with RFS but not OS in patients with early-stage EEC who were treated with adjuvant radiation therapy. These findings suggest that differential approaches to surveillance and/or treatment based on MMR status could be warranted.

The prognostic impact of substantial lymphovascular space invasion in women with node negative FIGO stage I uterine carcinoma

OBJECTIVE

Substantial lymphovascular space invasion (LVSI) is an important predictor of lymph node (LN) involvement in women with endometrial carcinoma. We studied the prognostic significance of substantial LVSI in patients with 2009-FIGO stage-I uterine endometrioid adenocarcinoma (EC) who all had pathologic negative nodal evaluation (PNNE).

METHODS

Pathologic specimens were retrieved and LVSI was quantified (focal or substantial) in women with stage-I EC who had a hysterectomy and PNNE. In addition to multivariate analysis (MVA), recurrence-free (RFS), disease-specific (DSS), and overall (OS) survival was compared between women with focal vs. substantial LVSI.

RESULTS

1052 patients were identified with a median follow-up of 9.7 years. 358 women (34%) received adjuvant radiotherapy. 907 patients (86.2%) had no LVSI, 87 (8.3%) had focal, and 58 (5.5%) had substantial LVSI. Five-year RFS was 93.3% (95% CI: 91.5-95.1), 76.8% (95% CI: 67.2-87.7) and 79.1% (95% CI: 67.6-95.3) for no, focal, and substantial LVSI(p < 0.0001). There was no statistically significant difference in 5-year RFS, DSS, OS, and in the patterns of initial recurrence between women with focal vs substantial LVSI. On MVA with propensity score matching, substantial LVSI was not independently associated with any survival endpoint compared to focal LVSI, albeit both were detrimental when compared to no LVSI. Age ≥ 60 years and higher grade were predictors of worse RFS, DSS, and OS. Additionally, comorbidity burden was an independent predictor for OS.

CONCLUSIONS

Our results suggest that substantial LVSI does not predict worse survival endpoints or different recurrence patterns in women with stage-I EC with PNNE when compared to focal LVSI.

Prognostic impact and causality of age on oncological outcomes in women with endometrial cancer: a multimethod analysis of the randomised PORTEC-1, PORTEC-2, and PORTEC-3 trials

BACKGROUND

Numerous studies have shown that older women with endometrial cancer have a higher risk of recurrence and cancer-related death. However, it remains unclear whether older age is a causal prognostic factor, or whether other risk factors become increasingly common with age. We aimed to address this question with a unique multimethod study design using state-of-the-art statistical and causal inference techniques on datasets of three large, randomised trials.

METHODS

In this multimethod analysis, data from 1801 women participating in the randomised PORTEC-1, PORTEC-2, and PORTEC-3 trials were used for statistical analyses and causal inference. The cohort included 714 patients with intermediate-risk endometrial cancer, 427 patients with high-intermediate risk endometrial cancer, and 660 patients with high-risk endometrial cancer. Associations of age with clinicopathological and molecular features were analysed using non-parametric tests. Multivariable competing risk analyses were performed to determine the independent prognostic value of age. To analyse age as a causal prognostic variable, a deep learning causal inference model called AutoCI was used.

FINDINGS

Median follow-up as estimated using the reversed Kaplan-Meier method was 12·3 years (95% CI 11·9-12·6) for PORTEC-1, 10·5 years (10·2-10·7) for PORTEC-2, and 6·1 years (5·9-6·3) for PORTEC-3. Both overall recurrence and endometrial cancer-specific death significantly increased with age. Moreover, older women had a higher frequency of deep myometrial invasion, serous tumour histology, and p53-abnormal tumours. Age was an independent risk factor for both overall recurrence (hazard ratio [HR] 1·02 per year, 95% CI 1·01-1·04; p=0·0012) and endometrial cancer-specific death (HR 1·03 per year, 1·01-1·05; p=0·0012) and was identified as a significant causal variable.

INTERPRETATION

This study showed that advanced age was associated with more aggressive tumour features in women with endometrial cancer, and was independently and causally related to worse oncological outcomes. Therefore, our findings suggest that older women with endometrial cancer should not be excluded from diagnostic assessments, molecular testing, and adjuvant therapy based on their age alone.

FUNDING

None.

Prediction of recurrence risk in endometrial cancer with multimodal deep learning

Predicting distant recurrence of endometrial cancer (EC) is crucial for personalized adjuvant treatment. The current gold standard of combined pathological and molecular profiling is costly, hampering implementation. Here we developed HECTOR (histopathology-based endometrial cancer tailored outcome risk), a multimodal deep learning prognostic model using hematoxylin and eosin-stained, whole-slide images and tumor stage as input, on 2,072 patients from eight EC cohorts including the PORTEC-1/-2/-3 randomized trials. HECTOR demonstrated C-indices in internal (n = 353) and two external (n = 160 and n = 151) test sets of 0.789, 0.828 and 0.815, respectively, outperforming the current gold standard, and identified patients with markedly different outcomes (10-year distant recurrence-free probabilities of 97.0%, 77.7% and 58.1% for HECTOR low-, intermediate- and high-risk groups, respectively, by Kaplan-Meier analysis). HECTOR also predicted adjuvant chemotherapy benefit better than current methods. Morphological and genomic feature extraction identified correlates of HECTOR risk groups, some with therapeutic potential. HECTOR improves on the current gold standard and may help delivery of personalized treatment in EC.

Screening for ferroptosis genes related to endometrial carcinoma and predicting of targeted drugs based on bioinformatics

Endometrial carcinoma is one of most common malignant tumors in women, and ferroptosis is closely related to the development and treatment of endometrial carcinoma. The aim of this study was to screen ferroptosis-related genes associated with endometrial carcinoma and predict targeted drugs through bioinformatics. 761 differentially expressed genes were obtained by the dataset GSE63678 from the GEO database, and most of the genes were enriched in the KEGG_CELL_CYCLE and KEGG_OOCYTE_MEIOSIS signaling pathways. 22 ferroptosis-differentially expressed genes were obtained by intersection with the FerrDb database. These genes were involved in biological processes including macromolecular complex assembly and others, and involved in signal pathways including glutathione metabolism, p53 signaling pathway and others. CDKN2A, IDH1, NRAS, TFRC and GOT1 were obtained as hub genes by PPI network analysis. GEPIA showed that CDKN2A, IDH1, NRAS and TFRC were significantly expressed in endometrial carcinoma. Immunohistochemical results showed that CDKN2A, NRAS and TFRC were significantly expressed in endometrial carcinoma clinical tissue samples. The ROC constructed by TCGA database showed that CDKN2A, NRAS and TFRC had significant value in the diagnosis of endometrial carcinoma, and all had prognostic efficacy. 136,572-09-3 BOSS and others were identified as potential targeted drugs for endometrial carcinoma targeting ferroptosis. Our study has shown that ferroptosis-related genes CDKN2A, NRAS and TFRC are diagnostic markers of endometrial carcinoma, and 136,572-09-3 BOSS, methyprylon BOSS, daunorubicin CTD 00005752, nitroglycerin BOSS and dUTP BOSS, IRON BOSS, Imatinib mesylate BOSS, 2-Butanone BOSS, water BOSS, and L-thyroxine BOSS may be potential therapeutic drugs.

Endometrial Cancer: 2023 Revised FIGO Staging System and the Role of Imaging

The FIGO endometrial cancer staging system recently released updated guidance based on clinical evidence gathered after the previous version was published in 2009. Different imaging modalities are beneficial across various stages of endometrial cancer (EC) management. Additionally, ongoing research studies are aimed at improving imaging in EC. Gynecological cancer is a crucial element in the practice of a body radiologist. With a new staging system in place, it is important to address the role of radiology in the EC diagnostic pathway. This article is a comprehensive review of the changes made to the FIGO endometrial cancer staging system and the impact of imaging in the staging of this disease.

Can an in-person hands-on applicator-based teaching session improve trainee knowledge and comfort with complex gynecologic brachytherapy?

INTRODUCTION

With the emergence of imaged-based planning and hybrid applicators the complexity of gynecologic brachytherapy has dramatically increased. Despite the known advantages of brachytherapy, notable national declines in utilization of brachytherapy have been documented. Clearly improved education in the sphere of gynecologic brachytherapy is needed. We hypothesize that a hands-on applicator-based training session would improve trainee comfort with gynecologic brachytherapy.

METHODS AND MATERIALS

An in-person, applicator-based, hands-on training session was held with trainees from both radiation and gynecologic oncology programs. Trainees practiced assembling and handling applicators while receiving instruction on clinical scenarios in which various applicators are used in gynecologic cancer brachytherapy. Pre- and post-session, participants were administered an objective test of 10 pictorial-based case vignettes to quantify ability to select the correct applicator based on the interpretation of T2-weighted MR images. Participants additionally received a subjective survey to quantify comfort and experience with gynecologic brachytherapy using Likert-type question formatting.

RESULTS

A total of 14 trainees participated. Most common case volume experience was 0-10 intracavitary (57%), 0-10 hybrid (71%), and 0-10 interstitial (71%). Pre-session, the most common answer to comfort level was "not comfortable still learning" for all brachytherapy types, and most common answer to largest gap in knowledge was all facets of brachytherapy. Average case-based test score was 3.5/10 pre-session versus 5.3/10 post-session (p = 0.028). Post-session, all respondents reported improved comfort level with brachytherapy. Post-session, most common answer to largest gap in knowledge was applicator/patient selection, and applicator/patient selection was also the largest area of identified improvement. 100% of participants felt repeating the session in the future would be helpful.

CONCLUSIONS

Hands-on training with applicators improves both subjective and objective comfort with gynecologic brachytherapy. With 100% of participants requesting to implement this session into resident training, we suggest national opportunities might exist to expand educational processes and improve utilization of complex gynecologic brachytherapy in practice.

Uncovering a novel DNA repair-related radiosensitivity model for evaluation of radiotherapy susceptibility in uterine corpus endometrial cancer

Background

Uterine corpus endometrial cancer (UCEC) exhibit heterogeneity in their DNA repair capacity, which can impact their response to radiotherapy. Our study aimed to identify potential DNA repair-related biomarkers for predicting radiation response in UCEC.

Methods

We conducted a thorough analysis of 497 UCEC samples obtained from TCGA database. Using LASSO-COX regression analysis, we constructed a radiosensitivity signature and subsequently divided patients into the radiosensitive (RS) and the radioresistant (RR) groups based on their radiosensitivity index. The GSVA and GSEA were performed to explore functional annotations. The CIBERSORT and ESTIMATE algorithms were utilized to investigate the immune infiltration status of the two groups. Additionally, we utilized the Tumor Immune Dysfunction and Exclusion (TIDE), Immunophenotype Score (IPS), and pRRophetic algorithms to predict the effectiveness of different treatment modalities.

Results

We constructed a radiosensitivity index consists of four DNA repair-related genes. Patients in the RS group demonstrated significantly improved prognosis compared to patients in the RR group when treated with radiotherapy. We observed that the RS group exhibited a higher proportion of the POLE ultra-mutated subtype, while the RR group had a higher proportion of the copy number high subtype. GSVA enrichment analysis revealed that the RS group exhibited enrichment in DNA damage repair pathways. Notably, the RS group demonstrated a higher proportion of naïve B cells and follicular helper T cells, while regulatory T cells (Tregs) and memory B cells were more abundant in the RR group. Furthermore, patients in the RS-PD-L1-high subgroup exhibited enrichment in immune-related pathways and increased sensitivity to immunotherapy, which is likely to contribute to their improved prognosis. Additionally, we conducted in vitro experiments to validate the expression of radiosensitivity genes in non-radioresistant (AN3CA) and radioresistant (AN3CA/IR) endometrial cancer cells.

Conclusions

In conclusion, our research successfully constructed a radiosensitivity signature with robust predictive capacity. These findings shed light on the association between immune activation, PD-L1 expression, and the response to immunotherapy in the context of radiotherapy.

Risk-Tailoring Radiotherapy for Endometrial Cancer: A Narrative Review

Endometrial cancer is the most common gynecologic cancer in the United States and it contributes to the second most gynecologic cancer-related deaths. With upfront surgery, the specific characteristics of both the patient and tumor allow for risk-tailored treatment algorithms including adjuvant radiotherapy and systemic therapy. In this narrative review, we discuss the current radiation treatment paradigm for endometrial cancer with an emphasis on various radiotherapy modalities, techniques, and dosing regimens. We then elaborate on how to tailor radiotherapy treatment courses in combination with other cancer-directed treatments, including chemotherapy and immunotherapy. In conclusion, this review summarizes ongoing research that aims to further individualize radiotherapy regimens for individuals in an attempt to improve patient outcomes.

The Role of Adjuvant Therapy for the Treatment of Micrometastases in Endometrial Cancer: A Systematic Review and Meta-Analysis

Endometrial cancer is the most incident gynecological cancer. Lymph node dissemination is one of the most important factors for the patient's prognosis. Pelvic lymph nodes are the primary site of extra-uterine dissemination in endometrial cancer (EC), setting the 5-year survival to 44-52%. It is standard practice for radiation therapy (RT) and/or chemotherapy (CTX) to be given as adjuvant treatments to prevent the progression of micrometastases. Also, administration of EC patients with RT and/or CTX regimens before surgery may decrease micrometastases, hence the need for lymphadenectomy. The primary aim of the systematic review and meta-analysis is to assess whether adjuvant RT and/or CTX improve oncological outcomes through the management of micrometastases and nodal recurrence. We performed systematic research using the string "Endometrial Neoplasms" [Mesh] AND "Lymphatic Metastasis/therapy" [Mesh]. The methods for this study were specified a priori based on the recommendations in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Outcomes were 5-year overall survival, progression-free survival, recurrence rate, and complications rate. We assessed the quality of studies using the Newcastle-Ottawa Scale (NOS). A total of 1682 patients with stage I-to-IV EC were included. Adjuvant treatment protocols involved external-beam RT, brachytherapy, and CTX either alone or in combination. The no-treatment group showed a non-statistically significant higher recurrence risk than any adjuvant treatment group (OR 1.39 [95% CI 0.68-2.85] p = 0.36). The no-treatment group documented a non-statistically significant higher risk of death than those who underwent any adjuvant treatment (RR 1.47 [95% CI 0.44-4.89] p = 0.53; I2 = 55% p = 0.000001). Despite the fact that early-stage EC may show micrometastases, adjuvant treatment is not significantly associated with better survival outcomes, and the combination of EBRT and CTX is the most valid option in the early stages.

Effects of vaginal dilation therapy on vaginal condition and sexual function of endometrial cancer patients treated with radiotherapy after surgery

OBJECTIVE

This study aimed to evaluate the effect of vaginal dilation therapy on vaginal length, vaginal stenosis, vaginal elasticity, and sexual function of endometrial cancer patients treated with radiotherapy after surgery.

METHODS

A total of 117 women were enrolled in this study. They received 6 months of vaginal dilation therapy. We evaluated their vaginal length, vaginal diameter, vaginal elasticity, and sexual function before radiotherapy, after radiotherapy, and after 6 months of vaginal dilation therapy. Their vaginal condition was assessed by customized vaginal dilating molds. Their sexual function was assessed by female sexual function index. The SPSS 25 software was used to analyze all the data.

RESULTS

According to multivariate analysis, vaginal diameter (β = 0.300, 95% CI [0.217-1.446], p = 0.010) and sexual intercourse frequency before diagnosis (β = 0.424, 95% CI [0.164-0.733], p = 0.006) were significantly correlated with female sexual function after radiotherapy. Vaginal dilation therapy helped increase vaginal length, improve vaginal stenosis and sexual function (p < 0.05), though most of the figures at the end of the intervention did not fully return to those before radiotherapy. Noticeably, vaginal dilation therapy was ineffective in improving vaginal elasticity and the incidence rate of female sexual dysfunction (p > 0.05). Moreover, patients with medium or good vaginal elasticity benefited more from vaginal dilation therapy than patients with poor vaginal elasticity (p < 0.05).

CONCLUSION

Vaginal dilation therapy should be carried out timely and preventatively in endometrial cancer patients treated with radiotherapy after surgery to improve their vaginal condition and sexual function.

Review of brachytherapy clinical trials: a cross-sectional analysis of ClinicalTrials.gov

INTRODUCTION

Characterizing the landscape of clinical trials including brachytherapy can provide an overview of the current status and research trends which may guide further areas of investigation.

METHOD

We queried 449,849 clinical trials from the ClinicalTrials.gov registry using brachytherapy-related keywords from 1980 to 2023, yielding 245 multi-arm and 201 single-arm, brachytherapy trials. Multi-arm and single-arm brachytherapy trials were compared using 12 trial protocol elements.

RESULTS

The number of trials including brachytherapy has increased over time, with over 60% of trials registered in 2010 onwards. The majority of clinical trials were Phase 2 or 3, evaluated both safety and efficacy, and were funded by academic sponsors. The most common tumor sites evaluated in brachytherapy clinical trials include prostate, cervix, liver, endometrium, and breast.

CONCLUSION

There remains continued interest in clinical trials including brachytherapy focused on evaluation of novel delivery systems, treatment planning, and new indications. More brachytherapy clinical trials are needed to define the optimal clinical utilization and advance prospective research in this field.

Treatment outcomes of early-stage endometrial cancer patients: A propensity score matching of vaginal brachytherapy versus pelvic radiotherapy

OBJECTIVES

This study aimed to report the treatment outcomes of radiation therapy for early-stage endometrial cancer patients. In addition, this study intended to identify high-risk factors that require pelvic radiotherapy (PRT) in addition to vaginal brachytherapy (VBT) for intermediate-risk endometrial cancer patients.

METHODS

Patients with early-stage endometrial cancer receiving postoperative VBT alone or with PRT were included. Propensity score matching was used to balance the two study groups. The primary endpoint was locoregional recurrence (LRR). Age-adjusted Charlson comorbidity index and substantial lymphovascular space invasion were selected for subgroup analyses to identify the benefits of PRT over VBT alone.

RESULTS

From 2005 to 2017, a total of 288 patients underwent analysis following propensity score matching. Of these, 144 received VBT and 144 received PRT. There was no significant difference in 5-year LRR between VBT and PRT for both intermediate (0% vs. 0%) and high-intermediate risk patients (3.5% VBT vs. 5.4% PRT; HR 0.54: 0.05-6.00; p = 0.616). The subgroup analyses revealed no significant factors favoring PRT over VBT. Patients with high comorbidities may have higher risks of non-cancer death after receiving PRT.

CONCLUSIONS

Postoperative VBT alone is sufficient for early-stage intermediate-risk endometrial cancer patients.

The Prognostic Significance of the Depth of Cervical Stromal Invasion in Women With FIGO Stage II Uterine Endometrioid Carcinoma

OBJECTIVE

The objective of this study was to investigate the prognostic significance of the depth of cervical stromal invasion (CSI) in women with FIGO stage II uterine endometrioid adenocarcinoma (EC).

METHODS

Our database of women with EC was quired for patients with stage II EC. Pathologic slides were retrieved and reviewed by gynecologic pathologists to determine cervical stromal thickness and depth of CSI as a percentage of stromal thickness (%CSI). Kaplan-Meier, univariate, and multivariate analyses were used to compare recurrence-free, disease-specific (DSS), and overall survival (OS) between women who had<50% versus ≥50% CSI. Univariate and multivariate analyses were used to assess other prognostic variables associated with survival endpoints.

RESULTS

A total of 117 patients were included in our study who had hysterectomy between 1/1990 and 8/2021. Seventy-nine patients (68%) with <50% and 38 (32w%) with ≥50% CSI. After a median follow-up of 131 months, 5-year DSS was significantly worse for women with ≥50% CSI (78% vs. 91%; P =0.04). However, %CSI was not an independent predictor for any of the studied survival endpoints. Independent predictors of worse 5-year recurrence-free survival and DSS included FIGO grade 3 tumors ( P =0.02) and the presence of lymphovascular space invasion ( P =0.03). Grade 3 tumors were the only independent predictor of worse 5-year OS ( P =0.02).

CONCLUSIONS

Our results suggest that deep CSI is not an independent prognostic factor for survival endpoints in women with stage II uterine endometroid adenocarcinoma. The lack of independent prognostic significance of the depth CSI needs to be validated in a multi-institutional analysis.

Molecular Classification Predicts Response to Radiotherapy in the Randomized PORTEC-1 and PORTEC-2 Trials for Early-Stage Endometrioid Endometrial Cancer

PURPOSE

The molecular classification of endometrial cancer (EC) has proven to have prognostic value and is predictive of response to adjuvant chemotherapy. Here, we investigate its predictive value for response to external beam radiotherapy (EBRT) and vaginal brachytherapy (VBT) in early-stage endometrioid EC (EEC).

METHODS

Data of the randomized PORTEC-1 trial (n = 714) comparing pelvic EBRT with no adjuvant therapy in early-stage intermediate-risk EC and the PORTEC-2 trial (n = 427) comparing VBT with EBRT in early-stage high-intermediate-risk EC were used. Locoregional (including vaginal and pelvic) recurrence-free survival was compared between treatment groups across the four molecular classes using Kaplan-Meier's methodology and log-rank tests.

RESULTS

A total of 880 molecularly classified ECs, 484 from PORTEC-1 and 396 from PORTEC-2, were included. The majority were FIGO-2009 stage I EEC (97.2%). The median follow-up was 11.3 years. No locoregional recurrences were observed in EC with a pathogenic mutation of DNA polymerase-ε (POLEmut EC). In mismatch repair-deficient (MMRd) EC, locoregional recurrence-free survival was similar after EBRT (94.2%), VBT (94.2%), and no adjuvant therapy (90.3%; P = .74). In EC with a p53 abnormality (p53abn EC), EBRT (96.9%) had a substantial benefit over VBT (64.3%) and no adjuvant therapy (72.2%; P = .048). In EC with no specific molecular profile (NSMP EC), both EBRT (98.3%) and VBT (96.2%) yielded better locoregional control than no adjuvant therapy (87.7%; P < .0001).

CONCLUSION

The molecular classification of EC predicts response to radiotherapy in stage I EEC and may guide adjuvant treatment decisions. Omitting radiotherapy seems to be safe in POLEmut EC. The benefit of radiotherapy seems to be limited in MMRd EC. EBRT yields a significantly better locoregional recurrence-free survival than VBT or no adjuvant therapy in p53abn EC. VBT is the treatment of choice for NSMP EC as it is as effective as EBRT and significantly better than no adjuvant therapy for locoregional tumor control.

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.

Artificial intelligence applications in brachytherapy: A literature review

PURPOSE

Artificial intelligence (AI) has the potential to simplify and optimize various steps of the brachytherapy workflow, and this literature review aims to provide an overview of the work done in this field.

METHODS AND MATERIALS

We conducted a literature search in June 2022 on PubMed, Embase, and Cochrane for papers that proposed AI applications in brachytherapy.

RESULTS

A total of 80 papers satisfied inclusion/exclusion criteria. These papers were categorized as follows: segmentation (24), registration and image processing (6), preplanning (13), dose prediction and treatment planning (11), applicator/catheter/needle reconstruction (16), and quality assurance (10). AI techniques ranged from classical models such as support vector machines and decision tree-based learning to newer techniques such as U-Net and deep reinforcement learning, and were applied to facilitate small steps of a process (e.g., optimizing applicator selection) or even automate the entire step of the workflow (e.g., end-to-end preplanning). Many of these algorithms demonstrated human-level performance and offer significant improvements in speed.

CONCLUSIONS

AI has potential to augment, automate, and/or accelerate many steps of the brachytherapy workflow. We recommend that future studies adhere to standard reporting guidelines. We also stress the importance of using larger sample sizes and reporting results using clinically interpretable measures.

Acute and long-term toxicity of whole pelvis proton radiation therapy for definitive or adjuvant management of gynecologic cancers

OBJECTIVE

To characterize long-term toxicity and disease outcomes with whole pelvis (WP) pencil beam scanning proton radiation therapy (PBS PRT) for gynecologic malignancies.

METHODS

We reviewed 23 patients treated from 2013 to 2019 with WP PBS PRT for endometrial, cervical, and vaginal cancer. We report acute and late Grade (G)2+ toxicities, graded by Common Terminology Criteria for Adverse Events, Version 5. Disease outcomes were assessed by Kaplan-Meier method.

RESULTS

Median age was 59 years. Median follow up was 4.8 years. 12 (52.2%) had uterine cancer, 10 (43.5%) cervical, 1 (4.3%) vaginal. 20 (86.9%) were treated post-hysterectomy. 22 (95.7%) received chemotherapy, 12 concurrently (52.2%). The median PBS PRT dose was 50.4GyRBE (range, 45-62.5). 8 (34.8% had para-aortic/extended fields. 10 (43.5%) received brachytherapy boost. Median follow up was 4.8 years. 5-year actuarial local control was 95.2%, regional control 90.9%, distant control 74.7%, both disease control and progression-free survival 71.2%. Overall survival was 91.3%. In the acute period, 2 patients (8.7%) had G2 genitourinary (GU) toxicity, 6 (26.1%) had gastrointestinal (GI) G2-3 toxicity, 17 (73.9%) had G2-4 hematologic (H) toxicity. In the late period, 3 (13.0%) had G2 GU toxicity, 1 (4.3%) had G2 GI toxicity, 2 (8.7%) had G2-3H toxicity. The mean small bowel V15Gy was 213.4 cc. Mean large bowel V15 Gy was 131.9 cc.

CONCLUSIONS

WP PBS PRT for gynecologic malignancies delivers favorable locoregional control. Rates of GU and GI toxicity are low. Acute hematologic toxicity was most common, which may be related to the large proportion of patients receiving chemotherapy.

Cost-effectiveness analysis of tumor molecular testing in stage III endometrial cancer

BACKGROUND

Standard of care for adjuvant treatment of stage III endometrial cancer includes chemotherapy and radiation. In addition to stage, tumor molecular profiles may predict treatment outcomes, and prospective clinical trials are ongoing. However, tumor molecular testing is costly and time-consuming. Our objective was to evaluate the cost-effectiveness of tumor molecular testing in stage III endometrial cancer.

METHODS

A Markov decision model compared two strategies for stage III endometrial cancer: Tumor Molecular Testing (TMT) versus No TMT. TMT included sequential POLE next generation sequencing, mismatch repair immunohistochemistry (IHC), and p53 IHC. POLE-mutated patients were assigned to adjuvant radiation therapy; all others including controls were assigned to adjuvant chemoradiation. First recurrences were treated with 6 cycles of carboplatin and paclitaxel. Second recurrences were treated with pembrolizumab alone for mismatch repair deficient patients and both pembrolizumab and lenvatinib for other patients. Sensitivity analyses were performed to test model robustness.

RESULTS

Compared to No TMT, TMT was cost saving with equivalent effectiveness. On one-way sensitivity analysis, TMT remained cost saving over all parameter ranges. TMT was also favored on probabilistic sensitivity analysis in 80% of iterations at a willingness-to-pay threshold of $100,000/quality adjusted life-year (QALY) gained. However, when TMT was compared to mismatch repair IHC alone, TMT cost $182,798/QALY gained.

CONCLUSIONS

In this model of patients with stage III endometrial cancer, TMT was cost saving compared to No TMT. However, when compared to mismatch repair IHC alone, TMT was economically unfavorable.

Pelvic radiation-induced urinary strictures: etiology and management of a challenging disease

Radiation is a common treatment modality for pelvic malignancies. While it can be effective at cancer control, downstream effects can manifest months to years after treatment, leaving patients with significant morbidity. Within urology, a particularly difficult post-radiation consequence is urinary tract stricture, either of the urethra, bladder neck, or ureter. In this review, we will discuss the mechanism of radiation damage and treatment options for these potentially devastating urinary sequelae.