Clearance of the retropancreatic margin in pancreatic carcinomas: total mesopancreas excision or extended lymphadenectomy?

Monitoring Pre- and Post-Operative Immune Alterations in Patients With Locoregional Colorectal Cancer Who Underwent Laparoscopy by Single-Cell Mass Cytometry

Surgical excision is currently the principal therapy for locoregional colorectal cancer (CRC). However, surgical trauma leads to controlled tissue damage, causing profound alterations in host immunity and, in turn, affecting post-operative outcomes. Surgery-induced immune alterations in CRC remain poorly defined. Here, single-cell mass cytometry was applied to serial blood samples collected pre-operatively, and on days 1, 3, and 7 post-operatively from 24 patients who underwent laparoscopic surgical resection of CRC to comprehensively monitor the perioperative phenotypic alterations in immune cells and dynamics of immune response. Characterization of immune cell subsets revealed that the post-operative immune response is broad but predominantly suppressive, supported by the decreases in total frequencies of circulating T cells and natural killer (NK) cells, as well as decreased HLA-DR expression on circulating monocytes. The proportion of T cells significantly decreased on day 1 and recovered to the pre-surgical level on day 3 after surgery. The frequency of monocytes was significantly elevated on day 1 after surgery and declined to baseline level on day 3. NK cells temporarily contracted on post-operative day 3. T cells, monocytes, DCs, NK cells, and B cells were partitioned into phenotypically different single-cell clusters. The dynamics of single-cell clusters were different from those of the bulk lineages. T cell clusters in the same response phase fluctuate inconsistently during the perioperative period. Comparing to the baseline levels, the frequencies of CD11b(+)CD33(+)CD14(+)CD16(−) classical monocytes expanded followed by contraction, whereas CD11b(+)CD33(+)CD14(high)CD16(low) intermediate monocytes remained unchanged; HLA-DR expression in monocytes were significantly reduced; the frequencies of intermediate CD56(bright)CD16(+) NK cell subsets increased; and the percentage of memory B lymphocytes were elevated after surgery. Post-operative pro- and anti-inflammatory cytokines were both altered. Furthermore, perioperative immune perturbations in some of the cell subsets were unrecovered within seven days after surgery. Chronological monitoring major immune lineages provided an overview of surgery-caused alterations, including cell augments and contractions and precisely timed changes in immune cell distribution in both innate and adaptive compartments, providing evidence for the interaction between tumor resection and immune modulation.

"Mesopancreas-first" radical resection of pancreatic head cancer following the Cattell-Braasch-Valdoni maneuver: Appreciating the legacy of pioneers in visceral surgery

The “artery-first” approach pancreaticoduodenectomy, with maximal mesopancreas excision and central vascular ligation, represents the current principal determinants of radicality in pancreatic head cancer resection. However, these modifications at the resection stage of pancreaticoduodenectomy constitute extremely demanding and technically complicated procedures. Among the most critical contributing factors in the difficulty of artery-first approaches is the spiral configuration of the mesoduodenum and proximal mesojejunum around the superior mesenteric artery axis. This creates complicated tridimensional anatomy, making surgical dissection in the inferior peripancreatic anatomic area extremely challenging and demanding. The Cattell–Braasch–Valdoni maneuver (right-sided medial visceral mobilization and intestinal derotation maneuver) restores the embryological twist of the duodenojejunal junction, which demystifies the distorted peripancreatic vascular anatomy and facilitates a safe and radical “mesopancreas-first” pancreatic head cancer resection. The aim of this paper was to present the advantages, efficacy, and safety of the Cattell–Braasch–Valdoni maneuver in artery-first approach radical pancreaticoduodenectomy and provide a detailed description of its surgical technique.

Paraaortic dissection in "total mesopancreas excision" and "mesopancreas-first resection" pancreaticoduodenectomies for pancreatic cancer: Useless, optional, or necessary?A systematic review

The mesopancreas does not have well-defined boundaries but is continuous and connected through its components with the paraaortic area. The mesopancreatic resection margin has been indicated as the primary site for R1 resection after PD in pancreatic head cancer and total mesopancreas excision has been proposed to achieve adequate retropancreatic margin clearance and to minimize the likelihood of R1 resection. However, the anatomy of the mesopancreas requires extended dissection of the paraaortic area to maximize posterior clearance. The artery-first surgical approach has been developed to increase local radicality at the mesopancreatic resection margin. During PD, the artery-first approach begins with dissection of the connective tissues around the SMA. However, the concept of the mesopancreas as a boundless structure that includes circumferential tissues around the SMA, SMV, and paraaortic tissue highlights the need to shift from artery-first PD to mesopancreas-first PD to reduce the risk of R1 resection. From this perspective the "artery-first" approach, which allows for the avoidance of R2 resection risk, should be integrated into the "mesopancreas-first" approach to improve the R0 resection rate. In total mesopancreas excision and mesopancreas-first pancreaticoduodenectomies, the inclusion of the paraaortic area and circumferential area around the SMA in the resection field is necessary to control the tumour spread along the mesopancreatic resection margin rather than to control or stage the spread in the nodal basin.

Laparoscopic uncinate process first pancreatoduodenectomy-feasibility study of a modified 'artery first' approach to pancreatic head cancer

PURPOSE

The aim of this study was to discuss the feasibility of laparoscopic 'uncinate first' pancreatoduodenectomy.

METHODS

The analysis included prospectively collected data from 12 consecutive patients undergoing elective pure laparoscopic 'uncinate process first' pancreatoduodenectomy (Group 1). They were compared with patients previously operated on with a classical laparoscopic approach (Group 2). The primary outcome was the quality of the resected specimen (lymph node (LN) yield, R0 rate, involved resection margins). Secondary outcomes were perioperative parameters.

RESULTS

The LN yield in Group 1 was 19.3 and in Group 2 it was 13.9 (p = 0.03). R0 resection rates did not vary (66.7 vs. 63.2%, p = 0.84). Although the involvement of the superior mesenteric artery margin and uncinate process margin seemed lower in Group 1, the difference was not significant. Total operative time (467 vs. 425 min, p = 0.13) and resection time (221 vs. 232 min, p = 0.34) were similar in both groups. The estimated blood loss in Group 1 was 408 ml, whereas in Group 2 it was 392 ml (p = 0.33). Complication rates were 66.7% in Group 1 and 63.2% in Group 2 (p = 0.84). Median length of stay was 9 days in both groups (p = 0.36). Postoperative complication rates did not differ between groups.

CONCLUSIONS

Laparoscopic uncinate first approach is a feasible method for pancreatic head neoplasms. Achieved quality of the specimen is comparable with the traditional laparoscopic approach, whereas intra- and postoperative course is not inferior. However, further studies on larger cohorts are required to fully establish whether the novel approach has potential advantages over classical access in pancreatic head cancer.

R0 resection of pancreatic head carcinoma: Definition of surgical margins and influencing factors

Early diagnosis of pancreatic head carcinoma is difficult. Once diagnosed, it often has been in the advanced stage, the prognosis is poor, and five-year survival does not exceed 6%. R0 resection is the only way to obtain long-term survival in patients with pancreatic head cancer. Numerous clinical studies have shown that lack of retroperitoneal tissue dissection is the important reason for being unable to achieve R0 resection in pancreatic cancer patients. The proposed mesopancreas and total mesopancreas excision (TMpE) concept provides a better definition of retroperitoneal dissection, thereby increasing the rate of R0 resection effectively.

Mesopancreas: A boundless structure, namely the rationale for dissection of the paraaortic area in pancreaticoduodenectomy for pancreatic head carcinoma

This review highlights the rationale for dissection of the 16a2 and 16b1 paraaortic area during pancreaticoduodenectomy (PD) for carcinoma of the head of the pancreas. Recent advances in surgical anatomy of the mesopancreas indicate that the retropancreatic area is not a single entity with well defined boundaries but an anatomical site of embryological fusion of peritoneal layers, and that continuity exists between the neuro lymphovascular adipose tissues of the retropancreatic and paraaortic areas. Recent advances in surgical pathology and oncology indicate that, in pancreatic head carcinoma, the mesopancreatic resection margin is the primary site for R1 resection, and that epithelial-mesenchymal transition-related processes involved in tumor progression may impact on the prevalence of R1 resection or local recurrence rates after R0 surgery. These concepts imply that mesopancreas resection during PD for pancreatic head carcinoma should be extended to the paraaortic area in order to maximize retropancreatic clearance and minimize the likelihood of an R1 resection or the persistence of residual tumor cells after R0 resection. In PD for pancreatic head carcinoma, the rationale for dissection of the paraaortic area is to control the spread of the tumor cells along the mesopancreatic resection margin, rather than to control or stage the nodal spread. Although mesopancreatic resection cannot be considered “complete” or “en bloc”, it should be “extended as far as possible” or be “maximal”, including dissection of 16a2 and 16b1 paraaortic areas.

Mesopancreas: a boundless structure, namely R1 risk in pancreaticoduodenectomy for pancreatic head carcinoma

BACKGROUND

The mesopancreatic resection margin after pancreaticoduodenectomy for carcinoma of the head of the pancreas is of great interest with respect to curative resection, since the neoplastic involvement of this margin was shown to be the primary site for R1 resection. In this review the current knowledges of the surgical anatomy of the so-called mesopancreas and the mesopancreas excision techniques are summarized.

METHODS

References were identified by searching Pubmed database using the search terms "mesopancreas" and "meso-pancreatoduodenum" until June 2013 and through searches of the authors' own files. Five studies were included in this review.

RESULTS

Original contributions with regard to the anatomy of the retropancreatic area and specific technical descriptions of so-called "total mesopancreas excision" provided by published studies are pointed out.

CONCLUSIONS

Because there is no "meso" of the pancreas, and due to the continuity of the mesopancreatic and para-aortic areas, surgical dissection should be extended to the left of the superior mesenteric artery and include the para-aortic area to achieve the most complete possible resection of the so-called mesopancreas and minimize the rate of R1 resections due to mesopancreatic margin involvement. This extended mesopancreatic resection cannot be accomplished en bloc even if the removal of the dissected mesopancreatic tissues is performed en bloc with the head, uncus, and neck of the pancreas, i.e., with the pancreaticoduodenectomy specimen.