Despite progress in medicine, cancer represents the leading cause of death worldwide. At the time of diagnosis a large number of patients with solid tumours already feature metastatic lesions. Invisible minimal residual disease is always present after a tumour is removed and manifests itself only at a later stage when metastatic lesions become visible. The standard treatment protocol for the majority of patients with hematological malignancies and metastatic solid tumours is Chemotherapy. Chemotherapy may be an initially effective treatment but often there are malignant cells which are chemotherapy resistant and therefore are not affected. Cancer stem cells with primary resistant chemotherapy represent the major causes of treatment failure of cancer. Consequently, as soon as cancer cells become resistant to chemotherapy no cure is anticipated.
No cure is available for patients with metastatic cancer when tumour cells become resistant to available anticancer modalities. A cure may still be provided for patients with hematological malignancies despite resistance to available chemotherapy. Allogeneic (donor) cell therapy can be induced in conjunction with allogeneic stem cell transplantation with positive results. Allogeneic cell therapy by alloreactive lymphocytes and more innovative anti-cancer modalities focusing on immunotherapy may be effective for treatment of minimal residual disease as suggested by animal studies and pilot clinical trial. However, when cancer metastases recur, when tumour mass is large, even immunotherapy cannot effectively eliminate cancer metastases, which are currently available for elimination of minimal residual disease. Immunotherapy mediated by patients own immune system or by allogeneic lymphocytes may be effective against minimal residual disease but fails to eradicate visible tumours when tumour bulk is large and consists of rapidly progressing malignant cells. Consequently, successful treatment of patients with metastatic cancer depends in part on successful de-bulking to minimize tumour load. Unfortunately, surgical removal of metastatic lesions may not be feasible or may be associated with major procedural related complications and morbidity. Until recently, successful elimination of inoperable metastatic lesions remained the unachievable Holy Grail of oncologists. Development of ICS/HIFU and successful documentation of devitalization of metastatic lesions using non invasive procedures and using a safe outpatient procedure may revolutionize the field of oncology. A broad spectrum of metastatic cancers is subject to treatment by innovative approaches, but unknown by the vast majority of oncologists. The feasibility to devitalize and subsequently eliminate metastatic lesions that are otherwise resistant to any standard anti-cancer modality may provide for the first time an option for improving the outcome for patients with remote metastases. The ideal technique is a two step approach consisting of physical ablation of larger tumour bulks followed by more sophisticated methods for elimination of minimal residual disease.
Professor Shimon Slavin