When pancreatic cancer directly invades the spleen or spleen hilum, a concomitant splenectomy should be performed for a margin-negative resection. This allows for the potential clearance of regional lymph node metastasis around splenic hilar area when the cancer is located near the body of the pancreas [16, 17]. Then, the following questions become relevant: What do we know about the incidence of splenic hilar lymph node metastasis in left-sided pancreatic cancer? What is the oncologic impact of splenic hilar lymph node metastasis?

It is quite interesting to note that these questions were not seriously studied in the past. Only a few reports evaluated lymph node metastasis in resected left-sided pancreatic cancer. According to previously published literature [39, 40], splenic hilar lymph node metastasis was reported in 0–3.3% of resected left-sided pancreatic cancers, and there is little concern about the oncologic impact of splenic hilar lymph node metastasis in resected left-sided pancreatic cancer. Recently, a joint Korean and Japanese multicenter trial [41] evaluated the incidence of splenic hilar lymph node metastasis in resected left-sided pancreatic cancer, which was found to be 4.4%. It was also found that a small tumor size (<3 cm), proximal (neck/body) location, and no combined organ resection are predictive of no splenic hilar lymph node metastasis.

So far, there are two distal pancreatectomy techniques that allow for the spleen to be preserved. One is a splenic vessels-conserving technique [42], and another one is a splenic vessels-sacrificing approach, or the Warshaw’s procedure [43]. From the oncologic point of view, the splenic vessel-conserving technique is not appropriate for treating left-sided pancreatic cancer because lymph nodes surrounding the splenic vessels (No. 11) are the most frequent sites for lymph node metastasis, and pancreatic cancer frequently shows direct invasion to these vessels. Therefore, considering that the risk of splenic hilar lymph node metastasis is very low in left-side pancreatic cancer, modification of the splenic vessel-sacrificing technique for spleen-preserving LDP can lead to performing a radical pancreatectomy. This procedure involves removing the cancer and splenic hilar lymph node group using RAMPS while leaving the spleen intact.

In addition, the minimally invasive extended Warshaw procedure has been reported to be technically feasible [2, 3]. In fact, recent literature [44] demonstrated the oncologic reliability of spleen-preserving radical distal pancreatectomy for pancreatic cancer. They applied the Warshaw technique for radical pancreatectomy and reported 17 cases of spleen-preserving LDP. The average tumor size was 32±12 mm, and the average number of retrieved lymph nodes was 19.8±9.3. All resectional margin were found to be negative. Survival rates of the patients after 1, 3, and 5 years were 64.7, 52.9, and 41.2%, respectively, with similar outcomes observed in spleen-resecting LDP and open distal pancreatectomy (ODP) surgeries. No splenic hilar lymph node metastasis was reported. The role of spleen preservation as a postoperative adjuvant strategy for resected left-sided pancreatic cancer remains to be investigated [45–50].

In the case of pancreatic cancer invading the celiac axis and superior mesenteric vein-splenic vein-portal vein confluence, radical DPS combined with celiac axis excision and venous vascular resection can result in favorable outcomes in select patient groups [51–53]. It is also reported that the laparoscopic approach is also feasible in this kind of aggressive surgery, but only a few studies are currently available [54, 55]. Although the minimally invasive approach is technically feasible, the surgical technique is quite demanding. Only a few expert surgeons are able to execute this approach. Aggressive tumor biology and technical difficulty beg the question of oncologic efficacy and practical feasibility of minimally invasive surgery in this specific case (Fig. 15.1). Minimally invasive combined arterial or venous vascular resection in treating left-sided pancreatic cancer may not be generalized.

In order to lay the foundation for an evidence-based surgical approach, a randomized controlled trial (RCT) should be performed to test the reliability of laparoscopic radical DPS for treating left-sided pancreatic cancer. However, it is very difficult to organize a successful trial. There are not many surgeons capable of performing laparoscopic radical DPS, and the incidence of resectable pancreatic cancer that is potentially manageable by both laparoscopy and open radical DPS will be very low [38]. Considering that margin-negative resection is critical in treating pancreatic cancer, it may not be possible to randomize all resectable left-sided pancreatic cancers because some cases should be treated with open surgery due to the technical difficulty of obtaining a margin-negative resection. Therefore, in order to have a successful RCT for treating left-sided pancreatic cancer, a multicenter collaboration allow for a greater number of patients to be enrolled. In addition, among the patients with resectable pancreatic cancer, clinical subgroup needs to be defined in whom both laparoscopic and open radical DPS can easily produce margin-negative resection. Randomization should be done in those specific patients group. Surgical technique and postoperative management should also be standardized to minimize bias.

Alternatively, propensity score matching (PSM) is a statistical matching technique that minimizes selection bias and mimics randomization [56, 57]. Radical LDP remains controversial, and its clinical application to left-sided pancreatic cancer should be carefully considered based on the surgeons’ technique and oncologic philosophy, as margin-negative resection is critical for patient outcomes. As shown in Table 15.1, the number of the cases of radical LDP used to treating left-sided pancreatic cancer is increasing. To avoid ethical and scientific problems related to RCT in treating left-sided pancreatic cancer, a multicenter retrospective case collection with PSM analysis will be currently available potential strategies to validate the oncologic role of radical LDP [58–61].