Minimally invasive isolated limb perfusion – technical details and initial outcome of a new treatment method for limb malignancies

Isolated hyperthermic perfusions for cutaneous melanoma in-transit metastasis of the limb and uveal melanoma metastasis to the liver

Patients with cutaneous melanoma can develop in-transit metastases (ITM), most often localized to limbs. For patients with uveal melanoma that develop metastatic disease, the overall majority develop isolated liver metastases. For these types of metastases, regional cancer therapies have evolved as effective treatments. Isolated limb perfusion (ILP), isolated limb infusion (ILI), isolated hepatic perfusion (IHP) and percutaneous hepatic perfusion (PHP) achieve a high local concentration of chemotherapy with minimal systemic exposure. This review discusses the mechanism and available literature on locoregional treatment modalities in the era of modern immunotherapy.

Technical considerations for isolated limb perfusion: A consensus paper

BACKGROUND

Isolated limb perfusion (ILP) is a well-established surgical procedure for the administration of high dose chemotherapy to a limb for the treatment of advanced extremity malignancy. Although the technique of ILP was first described over 60 years ago, ILP is utilised in relatively few specialist centres, co-located with tertiary or quaternary cancer centres. The combination of high dose cytotoxic chemotherapy and the cytokine tumour necrosis factor alpha (TNFα), mandates leakage monitoring to prevent potentially serious systemic toxicity. Since the procedure is performed at relatively few specialist centres, an ILP working group was formed with the aim of producing technical consensus guidelines for the procedure to streamline practice and to provide guidance for new centres commencing the technique.

METHODS

Between October 2021 and October 2023 a series of face to face online and hybrid meetings were held in which a modified Delphi process was used to develop a unified consensus document. After each meeting the document was modified and recirculated and then rediscussed at subsequent meeting until a greater than 90% consensus was achieved in all recommendations.

RESULTS

The completed consensus document comprised 23 topics in which greater than 90% consensus was achieved, with 83% of recommendations having 100% consensus across all members of the working group. The consensus recommendations covered all areas of the surgical procedure including pre-operative assessment, drug dosing and administration, perfusion parameters, hyperthermia, leakage monitoring and theatre logistics, practical surgical strategies and also post-operative care, response evaluation and staff training.

CONCLUSION

We present the first joint expert-based consensus statement with respect to the technical aspects of ILP that can serve as a reference point for both existing and new centres in providing ILP.

European e-Delphi process to define expert consensus on electrochemotherapy treatment indications, procedural aspects, and quality indicators in melanoma

BACKGROUND

Skin metastases are an important co-morbidity in melanoma. Despite broad adoption, electrochemotherapy implementation is hindered by a lack of treatment indications, uncertainty regarding procedural aspects, and the absence of quality indicators. An expert consensus may harmonize the approach among centres and facilitate comparison with other therapies.

METHODS

An interdisciplinary panel was recruited for a three-round e-Delphi survey. A literature-based 113-item questionnaire was proposed to 160 professionals from 53 European centres. Participants rated each item for relevance and degree of agreement on a five-point Likert scale, and received anonymous controlled feedback to allow revision. The items that reached concordant agreement in two successive iterations were included in the final consensus list. In the third round, quality indicator benchmarks were defined using a real-time Delphi method.

RESULTS

The initial working group included 122 respondents, of whom 100 (82 per cent) completed the first round, thus qualifying for inclusion in the expert panel (49 surgeons, 29 dermatologists, 15 medical oncologists, three radiotherapists, two nurse specialists, two clinician scientists). The completion rate was 97 per cent (97 of 100) and 93 per cent (90 of 97) in the second and third rounds respectively. The final consensus list included 54 statements with benchmarks (treatment indications, (37); procedural aspects, (1); quality indicators, (16)).

CONCLUSION

An expert panel achieved consensus on the use of electrochemotherapy in melanoma, with a core set of statements providing general direction to electrochemotherapy users to refine indications, align clinical practices, and promote quality assurance programmes and local audits. The residual controversial topics set future research priorities to improve patient care.

Anti-PD-1 checkpoint blockade improves the efficacy of a melphalan-based therapy in experimental melanoma

INTRODUCTION

The induction of adaptive cellular immunity in patients with in-transit melanoma metastasis treated with hyperthermic isolated limb perfusion (ILP) with melphalan has been shown to contribute to the effectiveness of the therapy. Activated CD8⁺ T cells appear to be of particular importance for the efficacy of melphalan-based ILP therapy, as observed in both patients and animal models. In this study, we explored the possible synergistic effects of combining melphalan-based therapy with the checkpoint inhibitor anti-PD-1 on tumours in a mouse melanoma model.

METHODS

A murine vaccination model that utilized melphalan-exposed melanoma cells was used to mimic certain immunological features of melphalan-based ILP. The effects of the vaccine on tumour growth and PD-1 expression on CD8⁺ tumour-infiltrating T cells were analyzed. The melphalan-based vaccine was then combined with an anti-PD-1 antibody and tumour growth was assessed.

RESULTS

Treatment with melphalan-based therapy significantly induced the expression of PD-1 on CD8⁺ tumour-infiltrating lymphocytes. Combination therapy using melphalan-based therapy followed by treatment with PD-1 antibodies significantly reduced early-stage tumour growth relative to monotherapies and no treatment.

CONCLUSIONS

This study thus suggests that the addition of PD-1 blockade to melphalan-based therapies, such as ILP, may be therapeutically beneficial.

Leakage through the bone-marrow during isolated limb perfusion in the lower extremity

Isolated limb perfusion (ILP) is used for melanoma in-transit metastases of the extremities. The use of Melphalan and TNF-alpha, necessitates monitoring of possible systemic leakage throughout the perfusion. It has been suspected that leakage through bone marrow is possible. We present the case of a patient with in-transit melanoma metastases in the lower extremity, who underwent minimally invasive ILP, according to our new protocol through percutaneous insertion of the catheters under fluoroscopy. Following cannulation of the vessels a high leakage rate was recorded. The procedure was converted to open with clamping of the artery and vein, however the leakage was not possible to control, and venography showed that this was due to bone marrow veins. To the best of our knowledge this is the first case of a verified leakage during ILP through bone marrow veins. We believe that some minor leakages registered under ILP could be attributed to this leakage route.