A Review of Black Salve: Cancer Specificity, Cure, and Cosmesis

Abstract

Black salve is a topical escharotic used for the treatment of skin cancer. Although promoted as a safe and effective alternative to conventional management by its proponents, limited clinical research has been undertaken to assess its efficacy and potential toxicities. Patients are increasingly utilizing the Internet as a source of health information. As a minimally regulated space, the quality and accuracy of this information vary considerably. This review explores four health claims made by black salve vendors, investigating its natural therapy credentials, tumour specificity, and equivalence to orthodox medicine in relation to skin cancer cure rates and cosmesis. Based upon an analysis of in vitro constituent cytotoxicity, in vivo post black salve histology, and experience with Mohs paste, black salve is likely to possess normal tissue toxicity with some cancer cell lines being relatively resistant to its effects. This may explain the incongruous case study reports of excessive scarring, deformity, and treatment failure.

Figure 1

Major QBA cytotoxicity against normal and malignant cells 24 hr incubation. Data from [34, 69, 71]. Cell line: GF: gingival fibroblast; EK: epidermal keratinocyte; MDA-MB231: breast; HCT116: bowel; OVCAR-3: ovarian; A431: SCC; Du-145: prostate; MCF-7: breast; LNCaP: prostate.

Figure 2

Minor QBA cytotoxicity against normal and malignant cells 72 hr incubation. Data from [32, 35]. Cell line: LF: lung fibroblast; SF: skin fibroblast; HL60: leukaemia; A-2780: ovarian; HeLa: cervical; A431: SCC.