In this issue of JAMA Surgery, Cho et al1 discuss the deleterious effect of remnant liver ischemia (RLI) on the prognosis of patients with hepatocellular carcinoma (HCC). The authors classified the severity of RLI caused by unintentional damage to a segment’s inflow or outflow vessel according to the pragmatic definition by Gertsch et al2 and showed a dose-dependent negative effect on overall survival. This work is important not only because it defines the detrimental oncologic effect of RLI after hepatic resection for HCC but also because it establishes the existence of a prognostic factor under the control of the liver surgeon. An analogy to music can help illustrate the point: while the beauty of music created by a pianist is determined in part by a multitude of unchangeable factors (the piano, acoustics of the performance space, etc), it is ultimately the interpretive and technical virtuosity of the pianist that touches the audience. Similarly, while outcome in HCC is determined in part by predetermined factors, such as vascular invasion, the work by Cho et al1 reminds us that a surgeon’s skill crucially influences both short-term and long-term outcomes. Analysis of the data for multicollinearity could have assisted in determining the relative effect of tumor-specific factors compared with RLI on patient prognosis.
Yamashita S, Conrad C. A Prognostic Factor Under the Surgeon’s Control. JAMA Surg. Published online January 04, 2017. doi:10.1001/jamasurg.2016.5041