In patients with HPV-positive oropharyngeal cancer (OPC), lymph node ratio (LNR) may be a better predictor of survival and metastasis than lymph node (LN) number, reports a recent study.
Records of 90 patients were included in the present analysis. All were treated with surgery, with or without postoperative radiotherapy, from January 2000 to March 2019, with a median follow-up of 38.2 months.
Thirteen patients had no lymph node metastasis. Of the remaining patients, the median LNR, calculated as the ratio of metastatic to harvested lymph nodes, was 0.049. Receiver operating characteristic curve analysis found that LNR was a good predictor of patient survival (area under the curve [AUC], 0.669) and an even better indicator of recurrence (AUC, 0.842).
For recurrence and survival analysis, patients were divided into three groups of LNR (0, ≤0.5, and >0.5) and three groups of LN (0, 1–4, and >4).
Fifteen deaths and 11 recurrences were documented over the follow-up period, with a median time to the respective outcomes of 33.6 and 15.4 months. The 5-year overall survival (OS) estimates were 100 percent, 81.4 percent, and 72.1 percent in the three LN groups, respectively, with no significant differences reported (p=0.131)
The same was true for 5-year disease-free survival (DFS: 100 percent, 81.1 percent, and 75.2 percent, respectively; p=0.129).
In contrast, 5-year OS estimates for the respective LNR groups were 100 percent, 92.8 percent, and 65.0 percent, which reflected a statistically significant among-group difference (p=0.01). DFS also differed significantly among LNR groups (100 percent vs 89.3 percent vs 70.1 percent; p=0.012).
“In general, LNR could be considered more of a qualified metric for assessing LN burden. However, it is highly dependent on surgeon and pathologist factors. Currently, it is difficult to consider as a practical staging system,” the researchers said.
“Further research and consensus on surgical pathology will be needed to apply the LNR to clinical treatment and pathologic staging,” they added.