Clinical necessity of the immunohistochemical reassessment of para-aortic lymph nodes in resected pancreatic ductal adenocarcinoma

Resectable, borderline, and locally advanced pancreatic cancer-"the good, the bad, and the ugly" candidates for surgery?

The possibility of surgical resection strongly overrules medical oncologic treatment and is the only modality, causa sine qua non, long-term survival can be achieved in patients with pancreatic cancer. For this reason, the clinical classification of local resectability, subdividing tumors into resectable, borderline resectable, and locally advanced cancer, that is very technical in nature, is the one most widely used and accepted. As multimodality treatment with potent agents, particularly in the neoadjuvant setting, seems to be stepping forward as the new standard of treatment of pancreatic cancer, the established technical surgical landmarks tend to get challenged. This review aims to highlight the grey zones in the current classifications for local tumor involvement with respect to the observed patient outcome in the current multimodality treatment era. It summarizes the latest reported series on the outcome of resected primary resectable, borderline and locally advanced pancreatic cancer, and particularly vascular resections during pancreatectomy, in the background of different types of neoadjuvant therapy. It also hints what the new horizons of cancer biology tend to reveal whenever the technical hinders start being pushed aside. The current calls for the necessity of re-classification of the clinical categories of pancreatic cancer, from technically oriented to biology-focused individualized approach, are being elucidated.

Unexpected Para-aortic Lymph Node Metastasis in Pancreatic Ductal Adenocarcinoma: a Contraindication to Resection?

BACKGROUND

Margin-negative resection is the only cure for pancreatic cancer. However, para-aortic lymph node metastasis is considered a contraindication to curative resection in pancreatic cancer. To determine if there are long-term survival differences according to the presence or absence of para-aortic lymph node metastasis in patients undergoing pancreatectomy, we evaluated oncologic outcomes in resected pancreatic cancer with unexpected para-aortic lymph node metastasis confirmed on intraoperative frozen section biopsy.

METHODS

We retrospectively investigated 362 patients with pathologically confirmed pancreatic ductal adenocarcinoma who underwent pancreatectomy between 1996 and 2016.

RESULTS

Patients with a metastatic para-aortic lymph node had the poorest median disease-specific survival [hazard ratio 14, 95% confidence interval 10-19]. However, after chemotherapy, patients with a metastatic para-aortic lymph node had a much higher disease-specific survival rate (para-aortic lymph node+/postoperative chemotherapy- versus para-aortic lymph node+/postoperative chemotherapy+, P = 0.0003, adjusted P = 0.0015). Patients with a metastatic para-aortic lymph node who underwent postoperative chemotherapy had a similar survival benefit to patients with metastatic regional lymph node without para-aortic lymph node metastasis, regardless of postoperative chemotherapy (para-aortic lymph node+/postoperative chemotherapy+ versus regional lymph node+/postoperative chemotherapy-, P = 0.3047, adjusted P > 0.9999; para-aortic lymph node+/postoperative chemotherapy+ versus regional lymph node+/postoperative chemotherapy+, P = 0.0905, adjusted P = 0.4525).

CONCLUSIONS

Unexpected para-aortic lymph node metastasis on frozen section biopsy may no longer be a contraindication to curative resection in "resectable" pancreatic ductal adenocarcinoma, as long as postoperative adjuvant chemotherapy can be administered.

Positive para-aortic lymph nodes following pancreatectomy for pancreatic cancer. Systematic review and meta-analysis of impact on short term survival and association with clinicopathologic features

BACKGROUND

The relation between para-aortic lymph nodes (PALN) involvement and pancreatic ductal adenocarcinoma (PDAC) survival, along with the optimal handling of this particular lymph node station remain unclear. A systematic review and meta-analysis was performed to assess this.

METHODS

A search of Medline, Embase, Ovid and Cochrane databases was performed until July 2015 to identify studies reporting on the relation of PALN involvement and PDAC outcomes and a meta-analysis was performed following data extraction.

RESULTS

Ten retrospective studies and two prospective non randomized studies (2467 patients) were included. Patients with positive PALN had worse one (p < 0.00001) and two year (p < 0.00001) survival when compared with patients with negative PALN. Even when comparing only patients with positive lymph nodes (N1), patients with PALN involvement presented with a significant lower one (p = 0.03) and two (p = 0.002) year survival. PALN involvement was associated with an increased possibility of positive margin (R1) resection (p < 0.00001), stations' 12, 14 and 17 malignant infiltration (p < 0.00001), but not with tumour stage (p = 0.78).

DISCUSSION

Involvement of PALN is associated with decreased survival in pancreatic cancer patients. However, existence of long term survivors among this subgroup of patients should be further evaluated, in order to identify factors associated with their favourable prognosis.