Irreversible electroporation of tumors within the pelvic cavity

Malignancies that are notorious for their recurrence within the lesser pelvis following radiotherapy and/or surgery are female and male urogenital tract tumors and locoregional recurrences from gastrointestinal origin such as anorectal carcinomas [1, 2]. Due to ingrowth in or compression on peripheral nerves, these relapsing malignancies can cause aggravating pain and neural function loss. The presence of extensive adhesions induced by previous surgical procedures and the risk of radiation-induced toxicity in a previously irradiated area precludes radical local treatment options such as repeat surgery [3] and stereotactic ablative body radiation therapy (SABR) [4-6]. The risk of severe treatment-induced morbidity does not seem to outweigh clinical benefit [2, 7, 8]. In general, therapy for this specific patient population primarily aims at prolonging the - preferably quality-preserved - life span, and most patients will be referred to medical oncologists for either palliative chemotherapy or best supportive care. Selected patients can be offered other local treatment modalities such as radiofrequency ablation (RFA) or cryotherapy [9-11]. One important drawback of these thermal treatment modalities is the high risk of inducing thermal damage to important neural structures like the sciatic nerve or presacral plexus, as well as to the intestines, ureters, and large vessels [12, 13].