Electrochemotherapy pre-treatment in primary squamous vulvar cancer. Our preliminary experience

Pulsed Electric Fields in Oncology: A Snapshot of Current Clinical Practices and Research Directions from the 4th World Congress of Electroporation

The 4th World Congress of Electroporation (Copenhagen, 9-13 October 2022) provided a unique opportunity to convene leading experts in pulsed electric fields (PEF). PEF-based therapies harness electric fields to produce therapeutically useful effects on cancers and represent a valuable option for a variety of patients. As such, irreversible electroporation (IRE), gene electrotransfer (GET), electrochemotherapy (ECT), calcium electroporation (Ca-EP), and tumour-treating fields (TTF) are on the rise. Still, their full therapeutic potential remains underappreciated, and the field faces fragmentation, as shown by parallel maturation and differences in the stages of development and regulatory approval worldwide. This narrative review provides a glimpse of PEF-based techniques, including key mechanisms, clinical indications, and advances in therapy; finally, it offers insights into current research directions. By highlighting a common ground, the authors aim to break silos, strengthen cross-functional collaboration, and pave the way to novel possibilities for intervention. Intriguingly, beyond their peculiar mechanism of action, PEF-based therapies share technical interconnections and multifaceted biological effects (e.g., vascular, immunological) worth exploiting in combinatorial strategies.

Electrochemotherapy with intravenous bleomycin for heavily pre-treated vulvar cancer patients

OBJECTIVE

The management of vulvar cancer recurrences is complicated by patients' advanced age and comorbidities. Bleomycin-based electrochemotherapy is a potential treatment option in this setting. However, no data on long-term outcomes are available. Therefore, a multicenter observational study was designed to evaluate the 5-year results in these patients.

METHODS

Data about patients and tumor characteristics, electrochemotherapy cycles, clinical response, and follow-up were recorded. Treatment procedures were performed according to the European Standard Operating Procedures of Electrochemotherapy (ESOPE) guidelines. Response was evaluated according to the Response Evaluation Criteria in Solid Tumors (RECIST) criteria.

RESULTS

Fifty-one patients (mean age 82.31±7.28 years) with squamous cell vulvar cancer underwent electrochemotherapy (median number of sessions 1; range 1-4). 20 patients had complete response and 32% of these were disease-free after 2 years (median progression-free survival 16.8 months). In 13 patients with partial response the median progression-free survival was 15.36 months, while patients with stable or progressive disease showed tumor relapse after 6.95 and 3.26 months, respectively (p<0.001). Median overall survival was 18.77, 13.07, 6.73, and 11.13 months in patients with complete response, partial response, stable disease, and progressive disease, respectively (p=0.001).

CONCLUSION

Long-term follow-up of vulvar cancer patients showed reasonable tumor control after electrochemotherapy and improved progression-free survival and overall survival in responder subjects compared with non-responders. Further studies aimed at improving local response after electrochemotherapy are warranted. Thus, this approach represents a potential alternative for these patients.

Treatment of vulvar cancer recurrences with electrochemotherapy - a detailed analysis of possible causes for unsuccessful treatment

BACKGROUND

Electrochemotherapy has good local effectiveness in the treatment of vulvar cancer. Most studies have reported the safety and effectiveness of electrochemotherapy for palliative treatment of gynecological cancers and mostly vulvar squamous cell carcinoma. Some tumors, however, fail to respond to electrochemotherapy. The biological features/determinants for the nonresponsiveness are not determined yet.

PATIENT AND METHODS

A recurrence of vulvar squamous cell carcinoma was treated by electrochemotherapy using intravenous administration of bleomycin. The treatment was performed by hexagonal electrodes according to standard operating procedures. We analyzed the factors that could determine nonresponsiveness to electrochemotherapy.

RESULTS

Based on the presented case of nonresponsive vulvar recurrence to electrochemotherapy, we hypothesize that the vasculature of the tumors prior to treatment may predict the response to electrochemotherapy. The histological analysis showed minimal presence of blood vessels in the tumor. Thus, low perfusion may reduce drug delivery and lead to a lower response rate because of the minor antitumor effectiveness of vascular disruption. In this case, no immune response in the tumor was elicited by electrochemotherapy.

CONCLUSIONS

In this case, of nonresponsive vulvar recurrence treated by electrochemotherapy, we analyzed possible factors that could predict treatment failure. Based on histological analysis, low vascularization of the tumor was observed, which hampered drug delivery and distribution and resulted in no vascular disrupting action of electro-chemotherapy. All these factors could contribute to ineffective treatment with electrochemotherapy.

Electroporation and Electrochemotherapy in Gynecological and Breast Cancer Treatment

Gynecological carcinomas affect an increasing number of women and are associated with poor prognosis. The gold standard treatment plan is mainly based on surgical resection and subsequent chemotherapy with cisplatin, 5-fluorouracil, anthracyclines, or taxanes. Unfortunately, this treatment is becoming less effective and is associated with many side effects that negatively affect patients’ physical and mental well-being. Electroporation based on tumor exposure to electric pulses enables reduction in cytotoxic drugs dose while increasing their effectiveness. EP-based treatment methods have received more and more interest in recent years and are the subject of a large number of scientific studies. Some of them show promising therapeutic potential without using any cytotoxic drugs or molecules already present in the human body (e.g., calcium electroporation). This literature review aims to present the fundamental mechanisms responsible for the course of EP-based therapies and the current state of knowledge in the field of their application in the treatment of gynecological neoplasms.

Electrochemotherapy as an Alternative Treatment Option to Pelvic Exenteration for Recurrent Vulvar Cancer of the Perineum Region

Objective: Pelvic exenteration in women with recurrent vulvar carcinoma is associated with high morbidity and mortality and substantial treatment costs. Because pelvic exenteration severely affects the quality of life and can lead to significant complications, other treatment modalities, such as electrochemotherapy, have been proposed. The aim of this study was to evaluate the feasibility and suitability of electrochemotherapy in the treatment of recurrent vulvar cancer. We aimed to analyze the treatment options, treatment outcomes, and complications in patients with recurrent vulvar cancer of the perineum. Methods: A retrospective analysis of patients who had undergone pelvic exenteration for vulvar cancer at the Institute of Oncology Ljubljana over a 16-year period was performed. As an experimental, less mutilating treatment, electrochemotherapy was performed on one patient with recurrent vulvar cancer involving the perineum. Comparative data analysis was performed between the group with pelvic exenteration and the patient with electrochemotherapy, comparing hospital stay, disease recurrence after treatment, survival after treatment in months, and quality of life after treatment. Results: We observed recurrence of disease in 2 patients with initial FIGO stage IIIC disease 3 months and 32 months after pelvic exenteration, and they died of the disease 15 and 38 months after pelvic exenteration. Two patients with FIGO stage IB were alive at 74 and 88 months after pelvic exenteration. One patient with initial FIGO stage IIIC was alive 12 months after treatment with electrochemotherapy with no visible signs of disease progression in the vulvar region, and the lesions had a complete response. The patient treated with electrochemotherapy was hospitalized for 4 days compared with the patients with pelvic exenteration, in whom the average hospital stay was 19.75 (± 1.68) days. Conclusion: Our experience has shown that electrochemotherapy might be a less radical alternative to pelvic exenteration, especially for patients with initially higher FIGO stages.

New developments in rare vulvar and vaginal cancers

PURPOSE OF REVIEW

To provide the latest insight on the rare vulvar and vaginal malignancies, able to impact on clinical practice, and to outline new potential research developments.

RECENT FINDINGS

Many efforts are being made to produce technical and scientific advances in the fields of vulvar and vaginal carcinoma, including imaging work-up, interventional procedures and minimally invasive surgical approach, as well as molecular profiling and identification of new target treatments.

SUMMARY

In the evaluation of lymph node status, ultrasound has demonstrated promising results because of high predictive value, low risk and low cost. Positron Emission Tomography-Computed Tomography is confirmed to be reliable and should be prospectively investigated for its potential applications in radiomics, whilst Fusion-US could allow a precision guidance in diagnostics and interventional procedures. Regarding interventional procedure, surgery is becoming less invasive with the aim to increase quality of life; in carefully selected patients it would be possible to overcome the current strict criteria in the use of sentinel node biopsy. Future research should focus on potential target therapy, on the basis of tumor-specific biological features.Rare cancers should be referred to experienced centers with a high case flow, able to offer a full range of diagnostic and therapeutical options and a multidisciplinary approach. Networking should be encouraged to promote research opportunities and enable data sharing and multicenter trials.

Electrochemotherapy in Vulvar Cancer and Cisplatin Combined with Electroporation. Systematic Review and In Vitro Studies

Simple Summary

Electrochemotherapy (ECT) is an emerging treatment for solid tumors and an attracting research field due to its clinical results. ECT in association with bleomycin is an effective and safe treatment option in the vulvar cancer palliative setting. With regard to cisplatin (CSP)-based ECT, considering the clear evidence on its efficacy in gynecological tumors, the possibility to improve local control with CSP-based ECT is intriguing and a well-designed randomized clinical trial should be addressed to this issue.

Abstract

Electrochemotherapy (ECT) is an emerging treatment for solid tumors and an attractive research field due to its clinical results. This therapy represents an alternative local treatment to the standard ones and is based on the tumor-directed delivery of non-ablative electrical pulses to maximize the action of specific cytotoxic drugs such as cisplatin (CSP) and bleomycin (BLM) and to promote cancer cell death. Nowadays, ECT is mainly recommended as palliative treatment. However, it can be applied to a wide range of superficial cancers, having an impact in preventing or delaying tumor progression and therefore in improving quality of life. In addition, during the natural history of the tumor, early ECT may improve patient outcomes. Our group has extensive clinical and research experience on ECT in vulvar tumors in the palliative setting, with 70% overall response rate. So far, in most studies, ECT was based on BLM. However, the potential of CSP in this setting seems interesting due to some theoretical advantages. The purpose of this report is to: (i) compare the efficacy of CSP and BLM-based ECT through a systematic literature review; (ii) report the results of our studies on CSP-resistant squamous cell tumors cell lines and the possibility to overcome chemoresistance using ECT; (iii) discuss the future ECT role in gynecological tumors and in particular in vulvar carcinoma.

Literature Review and Our Experience With Bleomycin-Based Electrochemotherapy for Cutaneous Vulvar Metastases From Endometrial Cancer

Endometrial carcinoma is the most common gynecological malignancy and the fifth most common malignancy in women. The worldwide incidence is 15.9 new cases per 100,000 women per year, and the incidence in Europe is 22.7 new cases. Minority of cases are diagnosed at an advanced stage of the disease. Cutaneous metastases are very rare with a prevalence of 0.8%. If cutaneous metastases are present, the prognosis is poor with an overall survival of up to 12 months. In this review, we presented clinical data on treatment of gynecological cancers with electrochemotherapy, with focus on treatment of cutaneous vulvar metastases from endometrial cancer. Further, we present our data on the case of a 64-year-old woman with recurrent endometrial adenocarcinoma with vulvar skin metastases. Treatment of endometrial carcinoma metastases is multimodal with surgery, chemotherapy, radiotherapy and hormone treatment. There is still no consensus about the specific treatment of cutaneous metastases from endometrial cancer, in particular in order to release symptoms. Electrochemotherapy may be a treatment option to reduce pain and bleeding and a safe option to treat multiple skin metastases.

Quality of Life with Vulvar Carcinoma Treated with Palliative Electrochemotherapy: The ELECHTRA (ELEctroCHemoTherapy vulvaR cAncer) Study

Simple Summary

A multicenter prospective observational study was conducted on patients with vulvar cancer (VC) refractory or not amenable to standard therapies undergoing palliative electrochemotherapy (ECT) as per clinical practice. Electrochemotherapy with bleomycin improves quality of life in patients with recurrent vulvar cancer. The assessment was performed with a visual analog pain scale (VAS), EuroQol 5-Dimension 5-Level (EQ-5D-L5) and Functional Assessment of Cancer Therapy—Vulva cancer (FACT—V). To our knowledge, this is the first study reporting the impact of palliative ECT on QoL of VC patients, with a detailed evaluation of potential correlations between tumor characteristics and severity of and response to symptoms. This improvement is higher in patients with clinical response and for smaller and anterior lesions. Based on these results, ECT in VC should be considered as an effective option based on the favorable outcomes both in terms of response and QoL.

Abstract

The ELECHTRA (ELEctroChemoTherapy vulvaR cAncer) project was conceived to collect data on palliative electrochemotherapy (ECT) in vulvar cancer (VC) assessing patients’ outcomes (response and survival) and impact on quality of life (QoL). After reporting outcome data in 2019, here, we present the results on QoL. A multicenter prospective observational study was conducted on patients with VC refractory or not amenable to standard therapies undergoing palliative ECT as per clinical practice. The following questionnaires were administered before and after ECT (two and four months later, early and late follow-up): visual analog pain scale (VAS), EuroQol 5-Dimension 5-Level (EQ-5D-L5) and Functional Assessment of Cancer Therapy—Vulva cancer (FACT—V). Analyses were conducted on both the whole study population and by subgroups (clinical response after ECT and site, number and size of lesions). Questionnaires from 55 patients were evaluated. Compared to the baseline (6.1 ± 2.1), the VAS was significantly reduced at early (4.3 ± 2.5) and late follow-up (4.6 ± 2.8) (p < 0.0001). The FACT—V score improved significantly at early (9.6 ± 4.0) (p < 0.0001) and late follow-up (8.9 ± 4.1) (p < 0.0054) as compared to the baseline (7.1 ± 3.6). No EQ-5D-5L statistically significant changes were observed. Subgroup analyses showed worse QoL in patients with stable or progressive disease, posterior site and multiple or larger than 3 cm nodules. This is the first study reporting improved QoL in VC patients after palliative ECT. Based on these results, ECT in VC should be considered an effective option based on the favorable outcomes both in terms of response and QoL.

The Prognostic Role of the Surgical Margins in Squamous Vulvar Cancer: A Retrospective Australian Study

For the last 30 years at the Royal Hospital for Women, unifocal vulvar squamous cancers have been treated by radical local excision, aiming to achieve a histopathological margin of ≥8 mm, equating to a surgical margin of 1 cm. The need for a margin of this width has recently been challenged. We aimed to determine the long-term outcome following this conservative approach, and the relationship between vulvar recurrences and surgical margins. Data were obtained retrospectively on 345 patients treated primarily with surgery for squamous vulvar cancer between 1987 and 2017. Median follow-up was 93 months. Five-year disease-specific survival was 86%. Of 78 vulvar recurrences, 33 (42.3%) were at the primary site and 45 (57.7%) at a remote site. In multivariable analysis, a margin < 5 mm showed a higher risk of all vulvar (Hazard ratio (HR), 2.29; CI, 1.12-4.70), and primary site recurrences (subdistribution hazard ratio (SHR), 15.20; CI, 5.21-44.26), while those with a margin of 5 to <8 mm had a higher risk of a primary site recurrence (SHR, 8.92; CI, 3.26-24.43), and a lower risk of remote site recurrence. Excision margins < 8 mm treated by re-excision or radiation therapy had a significantly decreased risk of recurrence. Guidelines should continue to recommend a surgical margin of 1 cm.

Palliative electrochemotherapy in primary or recurrent vulvar cancer

OBJECTIVE

Since vulvar cancer is such a rare disease, the international experience with electrochemotherapy has been derived from only a few centers. The aim of this study was to evaluate clinical outcome and side effects profile with the use of electrochemotherapy in patients with primary or recurrent vulvar cancer.

METHODS

Data were retrospectively collected from November 2017 to November 2019 in two major Italian oncologic institutes: Regina Elena Institute and Fondazione Policlinico Universitario Agostino Gemelli IRCCS. Electrochemotherapy was offered in a palliative setting to patients with a primary or recurrent vulvar cancer who were not candidates for surgery or any other treatment, because of poor performance status or previous delivered treatments. All patients underwent general anesthesia. Electrical pulses were delivered using a pulse generator. Intravenous bleomycin was administered in conjunction with electrochemotherapy. Follow-up examinations were performed at 1, 3, and 6 months. Primary endpoint was to assess the response rate of electrochemotherapy as palliative treatment in patients with vulvar cancer.

RESULTS

A total of 15 patients were included in the study. Fourteen patients (93.3%) had a squamous cell carcinoma and one patient had vulvar carcinosarcoma. Ten patients (66.7 %) had a single lesion and 5 patients (33.3%) had multiple lesions. Median number of electrical pulses was 22 (range 3-42) and median operative time was 13 (range 7-20) min. No intra-procedure complications occurred. One patient had pneumonia during their post-operative stay. Overall response rate after 1 month was 80%. At the 3-month follow-up, 3 patients (20%) had disease progression, 3 patients (20%) had died from ongoing disease, 1 patient (6.7%) died for other reasons, whereas the other patients maintained their 1-month clinical response. A total of 8/13 patients (61.5%) were alive at 6-month follow-up, whereas 6/12 patients (50%) were alive at 1-year follow-up.

CONCLUSIONS

Electrochemotherapy is a feasible, easy to perform, and reproducible procedure in patients with primary or recurrent vulvar cancer who are unable to undergo surgery. Survival after 1 year in this population was 50%. Electrochemotherapy may have a role in the management of vulvar cancer, especially as palliative treatment when other therapies are no longer applicable.

Palliative treatment with electrochemotherapy in recurrent or metastatic vaginal cancer

OBJECTIVE

Vaginal metastases are very rare events with a poor prognosis. To improve the quality of life, local treatments should be considered. The aim of this study was to evaluate the role of electrochemotherapy as palliative treatment in vaginal cancer not amenable to standard treatments due to poor performance status, previous treatments, or advanced disease.

METHODS

This is a prospective observational study on patients diagnosed with vaginal cancer and treated from January 2017 to December 2018 with palliative electrochemotherapy. We collected data on patients with vaginal cancer treated by electrochemotherapy with the aim of local control. Data regarding electrochemotherapy, hospital stay, adverse events, and patient outcomes were analyzed. Intravenous bleomycin was injected as a bolus in 2-3 min at a dose of 15 000 UI/m2 and electrical pulses started 8 min after chemotherapy. Electrochemotherapy response was defined according to the Response Evaluation Criteria in Solid Tumors.

RESULTS

Five patients with vaginal recurrence (two squamous, two melanomas, and one leiomyosarcoma) and one with vaginal metastasis from intestinal adenocarcinoma received one treatment and two patients were re-treated. Imaging reported nodal metastasis (inguinal or pelvic) in two patients, distant metastases in two, and both node and distant metastasis in two patients, respectively. Response Evaluation Criteria in Solid Tumors showed a complete response in one patient, partial response in three patients, stable disease in one patient, and progressive disease in one patient, with an overall response rate of 67% and a clinical benefit rate (complete response, partial response, stable disease) of 83%. Two patients were re-treated and had a new response (partial response and stable disease, respectively). At last follow-up, two patients had died of the disease, two were alive with stable disease, one was alive with progressive disease, and one was alive without disease. Median post-electrochemotherapy overall survival was 12.9 months (range 1.6-26.9) and 1-year overall survival was 66.7%.

CONCLUSIONS

This preliminary experience showed a tumor response or stabilization in 83% of patients requiring palliative management for vaginal cancer. Further studies are needed to evaluate treatment outcome in larger and prospective series.

Use of electrochemotherapy in women with vulvar cancer to improve quality-of-life in the palliative setting: a meta-analysis

INTRODUCTION

Electrochemotherapy involves the use of transient tumor permeabilization via electric pulses in combination with low-dose chemotherapeutic agents. It has recently emerged as an alternative treatment modality in vulvar cancer. The aim of this meta-analysis was to ascertain the effectiveness of electrochemotherapy in the context of palliative care.

METHODS

The following databases were searched: MEDLINE, Scopus, and Cochrane Database, to identify all registered articles pertaining to palliative vulvar cancer treatment with electrochemotherapy from inception until August 2019, in line with PRISMA guidelines. A single-proportion meta-analysis was performed for the outcomes of overall response, complete response, partial response, stable disease, and progressive disease raterespectively, using the random-effect model. Sensitivity analysis was performed to address heterogeneity.

RESULTS

Four studies were included totaling 104 women. The studies were of moderate quality. Pooled results from four studies rendered a summary proportion of 78.8% (95% CI 70.4% to 86.1%) for the outcome of overall response. The median age ranged between 68 and 85 years. The sample size per study ranged between eight and 61 women. The tumors' histological types included: squamous-cell carcinoma (96.2%), Paget's disease (2.9%), and malignant melanoma (0.9%). A total of 65 patients (62.5%) presented with a single nodule, whilst 39 patients (37.5%) presented with multiple nodules. Eighty-nine women (85.6%) were previously submitted to other treatment modalities. The overall response rate ranged from 73.2% to 80.9%. The pooled proportion for the outcomes of complete and partial response rate was 48.7% (95% CI 30.74% to 61.5%) and 30.2% (95% CI 21.7% to 39.4%), respectively. The follow-up ranged from 1 to 51 months. No severe adverse effects were reported. The safety profile of electrochemotherapy was favorable.

CONCLUSIONS

Electrochemotherapy is an effective and minimally invasive treatment modality in the palliative care management of patients with vulvar cancer. The effective control of vulvar tumors by electrochemotherapy may contribute to improvement of quality-of-life. In light of the moderate quality of evidence, a multi-center cooperation is warranted to confirm its palliative benefit.

Electrochemotherapy of superficial tumors - Current status:: Basic principles, operating procedures, shared indications, and emerging applications

Treatment of superficial tumors with electrochemotherapy (ECT) has shown a steep rise over the past decade and indications range from skin cancers to locally advanced or metastatic neoplasms. Based on reversible electroporation, which is a physical method to achieve transient tumor cell membrane permeabilization by means of short electric pulses, ECT increases cellular uptake of bleomycin and cisplatin and their cytotoxicity by 8,000- and 80-fold, respectively. Standard operating procedures were established in 2006 and updated in 2018. Ease of administration, patient tolerability, efficacy across histotypes, and repeatability are peculiar advantages, which make standard ECT (ie, ECT using fixed-geometry electrodes) a reliable option for controlling superficial tumor growth locally and preventing their morbidity. Consolidated indications include superficial metastatic melanoma, breast cancer, head and neck skin tumors, nonmelanoma skin cancers, and Kaposi sarcoma. In well-selected patients with oropharyngeal cancers, ECT ensures appreciable symptom control. Emerging applications include skin metastases from visceral or hematological malignancies, vulvar cancer, and some noncancerous skin lesions (keloids and capillary vascular malformations). Repeatability and integration with other oncologic therapies allow for consolidation of response and sustained tumor control. In this review, we present the basic principles of ECT, recently updated operating procedures, anesthesiological management, and provide a synthesis of the efficacy of standard ECT across histotypes.

Electrochemotherapy - Emerging applications technical advances, new indications, combined approaches, and multi-institutional collaboration

The treatment of tumors with electrochemotherapy (ECT) has surged over the past decade. Thanks to the transient cell membrane permeabilization induced by the short electric pulses used by ECT, cancer cells are exposed to otherwise poorly permeant chemotherapy agents, with consequent increased cytotoxicity. The codification of the procedure in 2006 led to a broad diffusion of the procedure, mainly in Europe, and since then, the progressive clinical experience, together with the emerging technologies, have extended the range of its application. Herein, we review the key advances in the ECT field since the European Standard Operating Procedures on ECT (ESOPE) 2006 guidelines and discuss the emerging clinical data on the new ECT indications. First, technical developments have improved ECT equipment, with custom electrode probes and dedicated tools supporting individual treatment planning in anatomically challenging tumors. Second, the feasibility and short-term efficacy of ECT has been established in deep-seated tumors, including bone metastases, liver malignancies, and pancreatic and prostate cancers (long-needle variable electrode geometry ECT), and gastrointestinal tumors (endoscopic ECT). Moreover, pioneering studies indicate lung and brain tumors as suitable future targets. A further advance relates to new combination strategies with immunotherapy, gene electro transfer (GET), calcium EP, and radiotherapy. Finally and fourth, cross-institutional collaborative groups have been established to refine procedural guidelines, promote clinical research, and explore new indications.