A role for adjuvant radiation in clinically early carcinoma of the endometrium?

[Molecular-integrated risk profile: An opportunity for therapeutic de-escalation in intermediate and high-intermediate risk endometrial cancer]

In Europe, endometrial cancer is the fourth most common cancer among women. The majority of patients are diagnosed at a localized stage. For these patients, the standard of care is based on an hysterectomy with salpingo oophorectomy±lymph node staging. Through the assessment of histopathologic features, risk groups are determined: low, intermediate, high-intermediate, and high risk. Adjuvant strategies are guided by these risk groups. While the prognosis of low-risk and high-risk is well known, that of intermediate and high-intermediate risk is more heterogeneous, and the therapeutic index of adjuvant treatments is more questionable. Several trials (PORTEC [Post Operative Radiation Therapy in Endometrial Carcinoma] I, GOG [Gynecologic Oncology Group] 99, ASTEC [A Study in the Treatment of Endometrial Cancer] EN.5, PORTEC II, Sorbe et al trial) have assessed observation, vaginal cuff brachytherapy and/or pelvic external beam radiotherapy in this population. Vaginal cuff brachytherapy reduces the local recurrence rate, and pelvic external beam radiotherapy the pelvic recurrence rate. However, no benefit in terms of overall survival or occurrence of distant metastases is highlighted. Compared to observation, brachytherapy and above all external beam radiotherapy are associated with an increased morbidity, and with a decreased quality of life. In order to improve the therapeutic ratio and to optimize medico-economic decisions, therapeutic de-escalation strategies, based on the molecular profiles, are emerging in clinical trials, and in the recommendations for the management of intermediate and high-intermediate risk endometrial cancers. The four main molecular profiles highlighted by the genomic analyzes of The Cancer Genome Atlas (TCGA) - POLE (polymerase epsilon) mutation, non-specific molecular profile, MMR (MisMatch repair) deficiency, and p53 mutation - but also the quantification of lymphovascular space invasion (absent, focal or substantial), and the assessment of L1CAM (L1 cell adhesion molecule) overexpression represent growing concerns. Thus, the use of molecular-integrated risk profile to determine the best adjuvant treatment represent a major way to personalize adjuvant treatment of endometrial cancers, with therapeutic de-escalation opportunity for around half of the high-intermediate risks. However, in the absence of prospective data, inclusion in clinical trials assessing molecular profile-based treatment remains the best therapeutic opportunity.

Expression of periostin according to endometrial cancer grade

While various molecular profiling methods have been described for the early diagnosis and prognostic process of endometrial cancer, the most common gynaecological cancer, the data obtained remain insufficient. The present study aimed to investigate the protein and gene expression of periostin and its role as a new biomarker in the diagnosis, treatment and prognosis of endometrial cancer. A total of 15 patients diagnosed with endometrial cancer at the Department of Pathology, Zeynep Kamil Training and Research Hospital (Istanbul, Turkey) and 15 patients who were operated on for non-tumour-related reasons, between December 2019 and May 2020, were included in the study. The cases diagnosed with endometrial cancer were divided into three groups: International Federation of Gynaecology and Obstetrics grades I, II and III. Pathology tumour blocks were selected for enzyme-linked immunosorbent assay and PCR studies in which periostin gene expression and protein levels were measured, respectively. A significant increase in periostin gene expression was observed in the endometrial cancer samples compared with that in the controls (3.40±0.66 vs. 2.23±0.47). The protein level of periostin in the tissues was found to be higher in the endometrial cancer samples than that in the control group (1.59±0.31 vs. 0.94±0.22). The levels of periostin protein and gene expression detected in the endometrial cancer samples increased as the grade increased. To the best of our knowledge, the current study is the first to determine the levels of periostin protein and gene expression in endometrial cancer. The results suggested that periostin may be used as a biomarker in the determination of higher histological grade in endometrial cancer.

Vaginal brachytherapy management of stage I and II endometrial cancer

Adjuvant radiotherapy is an important component of post-operative therapy for patients with early-stage endometrial cancer. In the past decades, many trials have been conducted to determine the optimal adjuvant treatment strategy, pelvic external beam radiotherapy or vaginal brachytherapy. As a result, vaginal brachytherapy became the treatment of choice for patients with early-stage endometrial cancer at high-intermediate risk, based on clinicopathological risk factors. Vaginal brachytherapy maximizes local control and has only mild side effects with limited impact on quality of life, in comparison with pelvic external beam radiotherapy. The most frequently used treatment schedule is the one which was used in the PORTEC-2 trial (21 Gy in three fractions specified at 5 mm depth) and, whenever available, image-guided brachytherapy should be used. However, the most convenient and effective treatment schedule remains to be established. More recently, the discovery and integration of four molecular classes in the risk assessment of endometrial cancer patients has created new opportunities to prevent over- and undertreatment. The 2021 endometrial cancer guideline of the European Society of Gynaecological Oncology (ESGO), European Society for Radiotherapy and Oncology (ESTRO), and the European Society of Pathology (ESP) now proposes an integrated risk stratification, in which both clinicopathologic and molecular factors are combined, to direct adjuvant therapy. This rationale is now investigated in multiple prospective trials. This review provides an overview of the rationale and currently recommended and new strategies for vaginal brachytherapy in patients with stage I and II endometrial cancer.

Vaginal cuff brachytherapy for endometrial cancer: a review of major clinical trials with a focus on fractionation

The use of vaginal cuff brachytherapy in the adjuvant management of endometrial cancer has increased over time. Recommendations from the American Brachytherapy Society, American Society of Radiation Oncology, and European Society for Medical Oncology help to guide the application of vaginal cuff brachytherapy. However, wide variation in practice remains regarding treatment techniques. This article reviews the use of vaginal cuff brachytherapy in the post-operative management of endometrial cancer. It covers risk stratification, treatment rationale, outcomes, and treatment planning recommendations with a specific focus on dose-fractionation regimens. The authors performed a thorough literature review of articles pertinent to the goals of this review. Also presented are early results of the Short Course Adjuvant Vaginal Cuff Brachytherapy in Early Endometrial Cancer Compared with Standard of Care (SAVE) trial of a two-fraction vaginal cuff brachytherapy regimen.

Adjuvant vaginal cuff brachytherapy for early-stage endometrial cancer results in excellent disease control with minimal toxicity. The PORTEC-2 trial showed that vaginal cuff brachytherapy is non-inferior to external beam radiation for vaginal recurrence in patients at high-intermediate risk. Vaginal cuff brachytherapy may also be used as a boost following external beam radiation in combination with chemotherapy for high-risk histologies. Numerous techniques can be used for vaginal cuff brachytherapy, including various medical devices, dose-fractionation schedules, and treatment planning approaches. The early control results of the SAVE trial are promising and we are hopeful that this trial establishes two fraction regimens as a viable option for vaginal cuff brachytherapy.

Risk Reclassification of Patients with Endometrial Cancer Based on Tumor Molecular Profiling: First Real World Data

Recently, guidelines for endometrial cancer (EC) were released that guide treatment decisions according to the tumors' molecular profiles. To date, no real-world data regarding the clinical feasibility of molecular profiling have been released. This retrospective, monocentric study investigated the clinical feasibility of molecular profiling and its potential impact on treatment decisions. Tumor specimens underwent molecular profiling (testing for genetic alterations, (immune-)histological examination of lymphovascular space invasion (LVSI), and L1CAM) as part of the clinical routine and were classified according to the European Society for Medical Oncology (ESMO) classification system and to an integrated molecular risk stratification. Shifts between risk groups and potential treatment alterations are described. A total of 60 cases were included, of which twelve were excluded (20%), and eight of the remaining 48 were not characterized (drop-out rate of 16.7%). Molecular profiling revealed 4, 6, 25, and 5 patients with DNA polymerase-epsilon mutation, microsatellite instability, no specific molecular profile, and TP53 mutation, respectively. Three patients had substantial LVSI, and four patients showed high L1CAM expression. Molecular profiling took a median of 18.5 days. Substantial shifts occurred between the classification systems: four patients were upstaged, and 19 patients were downstaged. Molecular profiling of EC specimens is feasible in a daily routine, and new risk classification systems will change treatment decisions substantially.

Brachytherapy quality assurance in the PORTEC-4a trial for molecular-integrated risk profile guided adjuvant treatment of endometrial cancer

OBJECTIVE

The PORTEC-4a trial investigates molecular-integrated risk profile guided adjuvant treatment for endometrial cancer. The quality assurance programme included a dummy run for vaginal brachytherapy prior to site activation, and annual quality assurance to verify protocol adherence. Aims of this study were to evaluate vaginal brachytherapy quality and protocol adherence.

METHODS

For the dummy run, institutes were invited to create a brachytherapy plan on a provided CT-scan with the applicator in situ. For annual quality assurance, institutes provided data of one randomly selected brachytherapy case. A brachytherapy panel reviewed and scored the brachytherapy plans according to a checklist.

RESULTS

At the dummy run, 15 out of 21 (71.4%) institutes needed adjustments of delineation or planning. After adjustments, the mean dose at the vaginal apex (protocol: 100%; 7 Gy) decreased from 100.7% to 99.9% and range and standard deviation (SD) narrowed from 83.6-135.1 to 96.4-101.4 and 8.8 to 1.1, respectively. At annual quality assurance, 22 out of 27 (81.5%) cases had no or minor and 5 out of 27 (18.5%) major deviations. Most deviations were related to delineation, mean dose at the vaginal apex (98.0%, 74.7-114.2, SD 7.6) or reference volume length.

CONCLUSIONS

Most feedback during the brachytherapy quality assurance procedure of the PORTEC-4a trial was related to delineation, dose at the vaginal apex and the reference volume length. Annual quality assurance is essential to promote protocol compliance, ensuring high quality vaginal brachytherapy in all participating institutes.

Survey of current practices from an international task force for gynecological stereotactic ablative radiotherapy

Background

Stereotactic Ablative Radiotherapy (SABR) is an effective treatment that improves local control for many tumours. However, the role of SABR in gynecological cancers (GYN) has not been well-established. We hypothesize that there exists considerable variation in GYN-SABR practice and technique. The goal of this study is to describe clinical and technical factors in utilization of GYN-SABR among 11 experienced radiation oncologists.

Materials and methods

A 63 question survey on GYN-SABR was sent to 11 radiation oncologists (5 countries) who have published original research, conducted trials or have an established program at their institutions. Responses were combined and analyzed at a central institution.

Results

Most respondents indicated that salvage therapy (non-irradiated or re-irradiated field) for nodal (81%) and primary recurrent disease (91%) could be considered standard options for SABR in the setting of inability to administer brachytherapy. All other indications should be considered on clinical trials. Most would not offer SABR as a boost in primary treatment off-trial without absolute contraindications to brachytherapy. Multi-modality imaging is often (91%) used for planning including PET, CT contrast and MRI. There is a wide variation for OAR tolerances however small bowel is considered the dose-limiting structure for most experts (91%). Fractionation schedules range from 3 to 6 fractions for nodal/primary definitive and boost SABR.

Conclusions

Although SABR has become increasingly standard in other oncology disease sites, there remains a wide variation in both clinical and technical factors when treating GYN cancers. Nodal and recurrent disease is considered a potential indication for SABR whereas other indications should be offered on clinical trials. This study summarizes SABR practices among GYN radiation oncologists while further studies are needed to establish consensus guidelines for GYN-SABR treatment.

Ten-year results of the PORTEC-2 trial for high-intermediate risk endometrial carcinoma: improving patient selection for adjuvant therapy

Background

PORTEC-2 was a randomised trial for women with high-intermediate risk (HIR) endometrial cancer, comparing pelvic external beam radiotherapy (EBRT) with vaginal brachytherapy (VBT). We evaluated long-term outcomes combined with the results of pathology review and molecular analysis.

Methods

427 women with HIR endometrial cancer were randomised between 2002–2006 to VBT or EBRT. Primary endpoint was vaginal recurrence (VR). Pathology review was done in 97.4%, combined with molecular analysis.

Results

Median follow-up was 116 months; 10-year VR was 3.4% versus 2.4% for VBT vs. EBRT (p = 0.55). Ten-year pelvic recurrence (PR) was more frequent in the VBT group (6.3% vs. 0.9%, p = 0.004), mostly combined with distant metastases (DM). Ten-year isolated PR was 2.5% vs. 0.5%, p = 0.10, and DM 10.4 vs. 8.9% (p = 0.45). Overall survival for VBT vs. EBRT was 69.5% vs. 67.6% at 10 years (p = 0.72). L1CAM and p53-mutant expression and substantial lymph-vascular space invasion were risk factors for PR and DM. EBRT reduced PR in cases with these risk factors.

Conclusion

Long-term results of the PORTEC-2 trial confirm VBT as standard adjuvant treatment for HIR endometrial cancer. Molecular risk assessment has the potential to guide adjuvant therapy. EBRT provided better pelvic control in patients with unfavourable risk factors.

Molecular-integrated risk profile to determine adjuvant radiotherapy in endometrial cancer: Evaluation of the pilot phase of the PORTEC-4a trial

OBJECTIVE

The Post-Operative Radiation Therapy in Endometrial Carcinoma (PORTEC)-4a trial is a randomized trial for women with high-intermediate risk endometrial cancer (EC), comparing individualized adjuvant treatment based on a molecular-integrated risk profile to standard adjuvant treatment; vaginal brachytherapy. To evaluate patient acceptability and pathology logistics of determining the risk profile, a pilot phase was included in the study.

METHODS

PORTEC-4a is ongoing and the first 50 patients enrolled were included in the pilot phase. Primary endpoints of the pilot phase were patient acceptance, evaluated by analyzing the screening logs of the participating centers, and logistical feasibility of determination of the risk profile within 2 weeks, evaluated by analyzing the pathology database.

RESULTS

In the first year, 145 eligible women were informed about the trial at 13 centers, of whom 50 (35%) provided informed consent. Patient accrual ranged from 0 to 57% per center. Most common reasons for not participating were: not willing to participate in any trial (43.2%) and not willing to risk receiving no adjuvant treatment (32.6%). Analysis of the pathology database showed an average time between randomization and determination of the molecular-integrated risk profile of 10.2 days (1-23 days). In 5 of the 32 patients (15.6%), pathology review took >2 weeks.

CONCLUSIONS

The PORTEC-4a trial design was proven feasible with a satisfactory patient acceptance rate and an optimized workflow of the determination of the molecular-integrated risk profile. PORTEC-4a is the first randomized trial to investigate use of a molecular-integrated risk profile to determine adjuvant treatment in EC.

Radiation-induced vaginal stenosis: current perspectives

Treatment of gynecological cancer commonly involves pelvic radiation therapy (RT) and/or brachytherapy. A commonly observed side effect of such treatment is radiation-induced vaginal stenosis (VS). This review analyzed the incidence, pathogenesis, clinical manifestation(s) and assessment and grading of radiation-induced VS. In addition, risk factors, prevention and treatment options and follow-up schedules are also discussed. The limited available literature on many of these aspects suggests that additional studies are required to more precisely determine the best management strategy of this prevalent group after RT.

Treatment preferences and involvement in treatment decision making of patients with endometrial cancer and clinicians

BACKGROUND

Vaginal brachytherapy (VBT) in high-intermediate-risk endometrial cancer (EC) provides a significant reduction in the risk of local cancer recurrence, but without survival benefit and with increased mucosal atrophy. Five-year local control is estimated to be similar for VBT and a watchful waiting policy (WWP), in which patients receive VBT combined with external radiation in case of a recurrence. Our aim was to assess treatment preferences of EC patients and clinicians regarding VBT and WWP, and to evaluate their preferred and perceived involvement in treatment decision making.

METHODS

Interviews were held with 95 treated EC patients. The treatment trade-off method was used to assess the minimally desired benefit from VBT in local control. Patients' preferred and perceived involvement in decision making were assessed using a questionnaire. Seventy-seven clinicians completed a questionnaire assessing their minimally desired benefit and preferred involvement in decision making.

RESULTS

Minimally desired benefit of VBT was significantly lower for patients than for clinicians (median=0 vs 8%, P<0.001), for irradiated than for non-irradiated patients (median=0 vs 6.5%, P<0.001), and for radiation oncologists than for gynaecologists (median=4 vs 13%, P<0.001). Substantial variation existed within the groups of patients and clinicians. Participants preferred the patient and clinician to share in the decision about VBT. However, irradiated patients indicated low perceived involvement in actual treatment decision making.

CONCLUSIONS

We found variations between and within patients and clinicians in minimally desired benefit from VBT. However, the recurrence risk at which patients preferred VBT was low. Our results showed that patients consider active participation in decision making essential.