Case report: is necrotizing fasciitis in a rectal cancer patient after targeted systemic therapy related to the tumor site? - evidence from a hepatocellular carcinoma patient

Abstract Necrotizing fasciitis (NF) is a rare and life-threatening serious infectious disease, characterized by acute onset and rapid progress, leading to extensive necrosis of skin, soft tissue as well as fascia by a variety of aerobic and anaerobic bacteria, localized on external genitalia, scrotum, groin and perianal areas in males. There exist numerous common etiologies for NF, yet NF induced by malignant neoplasms is exceedingly rare. Several studies have reported that NF may be associated with tumor site (rectal/sigmoid colon cancer) and blood supply dysfunction caused by targeted therapy drugs (bevacizumab, aflibercept, ramucirumab). The perforation of colorectal cancer poses a unique risk factor for NF. However, in our two cases, the patient with rectal cancer received CapeOX (oxaliplatin + capecitabine) + bevacizumab + tislelizumab for 3 cycles without perforation but did develop NF. One month after debridement, the patient continued immunotherapy with tislelizumab alone for the fourth cycle and maintained for an additional 3 cycles without any recurrence of NF. Therefore, does the occurrence of NF correlate with the tumor site (rectum) and targeted immunotherapy? Another patient with hepatocellular carcinoma also developed NF after receiving 2 cycles of lenvatinib + sintilimab treatment. The third cycle of sintilimab immunotherapy was administered on the 13th day after operation, which was subsequently maintained for an additional 2 cycles without recurrence of NF. The absence of a direct correlation between hepatocellular carcinoma and rectal tumor location as well as immunotherapy, suggests that NF may be closely linked to targeted therapy.