International assessment and validation of the prognostic role of lymph node ratio in patients with resected pancreatic head ductal adenocarcinoma

Prognostic value of nodal staging classification and number of examined lymph nodes among patients with ampullary cancer

BACKGROUND

Metastatic disease in the regional lymph nodes (LNs) is a strong indicator of worse outcomes among patients after curative-intent resection of ampullary cancer (AC). This study aimed to ascertain the threshold number of examined LNs (ELNs) for AC to compare the prognosis accuracy of various nodal classification schemes relative to long-term prognosis.

METHODS

Patients who underwent pancreatoduodenectomy (PD) for AC (2004-2019) were identified using the National Cancer Database. Locally weighted regression scatter plot smoothing (LOWESS) curves were used to ascertain the optimal cut point for ELNs. The accuracy of the American Joint Committee on Cancer N classification, LN ratio, and log odds transformation (LODDS) ratio to stratify patients relative to survival was examined.

RESULTS

Among 8127 patients with AC, 67% were male with a median age of 67 years (IQR, 59-74). Tumors were most frequently classified as T3 (34.9%), followed by T2 (30.6%); T1 (12.9%) and T4 (17.6%) were less common. LN metastasis was identified in 4606 patients (56.7%). Among patients with nodal disease, 37.0% and 19.7% had N1 and N2 disease, respectively. The LOWESS curves identified an inflection cutoff point in the hazard of survival at 20 ELNs. The survival benefit of 20 ELNs was more pronounced among patients without LN metastasis vs patients with N1 disease (median overall survival [OS]: 54.1 months [IQR, 45.9-62.1] in ≥20 ELNs vs 39.0 months [IQR, 35.8-42.2] in <20 ELNs; P < .001) or N2 disease (median OS: 22.5 months [IQR, 18.9-26.2] in ≥20 ELNs vs 25.4 months [IQR, 23.3-27.6] in <20 ELNs; P < .001). When comparing the 4 different N classification schemes, the LODDS classification scheme yielded the highest predictive ability.

CONCLUSIONS

Evaluation of a minimum of 20 LNs was needed to stratify patients with AC relative to the prognosis and to minimize stage migration. The LODDS nodal classification scheme had the highest prognostic accuracy to differentiate survival among patients after PD for AC.

Oncological role of surgical resection in patients with pancreatic ductal adenocarcinoma with liver-only synchronous metastases in a single-center retrospective study

Background

Surgical resection for liver-only synchronous metastases of pancreatic ductal adenocarcinoma remains controversial. We investigated the role of conversion surgery in patients with a favorable response to systemic chemotherapy.

Methods

Patients (n=49) were diagnosed liver-only synchronous metastases using staging laparoscopy or open laparotomy between 2007 and 2022. Clinical outcomes were retrospectively compared among patients who underwent conversion surgery (n=10), upfront surgery with or without short-term neoadjuvant chemotherapy (UpS/short NAC) for oligometastases and occult metastases limited to the liver (n=8), and chemotherapy only for resectable or borderline resectable disease with occult liver-only metastases (n=31). The surgical indication of conversion surgery was fixed as the ABC criteria, namely, Anatomical objective response of disappearance of liver metastases on imaging studies, Biological response of CA19-9 level decrease to ≤150 U/mL, and Conditional response of surgical fitness. In addition to the above ABC criteria, tumor disappearance at the liver was repeatedly confirmed using staging laparoscopy (laparoscopic response; L), and metabolic complete responses were confirmed using positron emission tomography-computed tomography (CT) (metabolic response; M).

Results

Median survival time from initial treatment was 9.9 months [95% confidence interval (CI): 8.3-10.9] in the chemotherapy group, 10.4 months (95% CI: 6.6-17.8) in the UpS/short NAC group, and 36.7 months (95% CI: 19.0-84.8) in the conversion surgery group (conversion surgery vs. UpS/short NAC, P=0.002; conversion surgery vs. chemotherapy, P<0.001; UpS/short NAC vs. chemotherapy, P=0.554). One patient in the UpS/short NAC group and three in the conversion surgery group achieved 5-year survival. Among them, two patients with initially multiple liver metastases (≥10) in the conversion surgery group survived beyond 5 years. Only conversion surgery was a significant independent prognostic factor in a total cohort (hazard ratio; 0.173, P=0.002).

Conclusions

Conversion surgery, but not UpS/short NAC, may enhance survival in patients with synchronous liver metastases and favorably anatomical, biological and conditional responses to systemic chemotherapy.