Histotripsy for Peritoneal Tumour and Lymph Node: a Pilot Study

Peritoneal cancer is tricky to be managed. It is not easy to be detected or diagnosed at early stage without symptom, or with common symptoms of many diseases or discomfort and often leads to advance stage at time of diagnosis with few treatment options and limited life span. It is also challenging to handle peritoneal tumour as it usually involves large area in peritoneum, or spread widely throughout the surface of peritoneum if metastatic from other origins. Systemic therapy is the common way to treat peritoneal cacner if the disease is inoperable. However, the unsatisfied penetration rate significantly limits the anti-tumour effect of intraperitoneal chemotherapy even after various attempts and most approaches demonstrated limited efficiency. Effective treatment for peritoneal cancer is still scarce and necessary. While the tumour nature of peritoneal tumour consists of solid tumour and soft tissue tumour, depends on primary or secondary disease, Histotripsy, which can be used on most kinds of solid tumour as well as soft tissue tumour, may yield a new direction and insight on peritoneal cancer management.

Histotripsy is currently indicated for liver tumours, approved by FDA and has been investigated for many disease types in preclinical researches and carried out several clinical trials for liver tumour, benign prostatic hyperplasia, liver tumour combined with systemic therapy, renal tumour, pancreatic tumour, soft tissue tumours, abdominal tumour, calcific aortic valves, and pain in plantar fasciitis, with encouraging results in some clinical trials. As most clinical trials above are for solid tumour and soft tissue tumour that suit the tumour nature of peritoneal tumour, we believe that Histotripsy is also safe and feasible on human with peritoneal tumour. Considering nodal involvement also frequently comes with peritoneal cancer, we would like to conduct an investigation for Histotripsy in peritoneal tumour and lymph node.

Although the result of clinical trial in peritoneal tumour and lymph node are not available yet, HIFU (High Intensity Focused Ultrasound) as another non-invasive ablation also delivered by ultrasound wave which has been in clinical use for many years worldwide can be referenced for Histotripsy. The core difference of HIFU and Histotripsy is, HIFU employs thermal energy to induce coagulative necrosis, while Histotripsy utilises mechanical cavitation to disrupt tumour tissues and preserves adjacent critical structure without the issue of heat, which makes it safer than HIFU. According to some reviews of HIFU, it is obvious that HIFU is feasible and safe without significant adverse event for abdominal tumours including peritoneal tumour and lymph node. Consequently, Histotripsy as a non-thermal ablation and is considered to be safer than HIFU, should also be feasible and safe for peritoneal tumour and lymph node. Hence, it is time for Hong Kong to launch the investigation on the feasibility, safety, and efficacy of Histotripsy in peritoneal tumour and lymph node.