Neoadjuvant therapy vs. upfront surgery for resectable pancreatic cancer: An update on a systematic review and meta-analysis

Neoadjuvant and Adjuvant Chemotherapy for Pancreatic Adenocarcinoma: Literature Review and Our Experience of NAC-GS

In addition to established evidence of the efficacy of adjuvant chemotherapy (AC) for pancreatic ductal adenocarcinoma (PDAC), evidence of the effects of neoadjuvant treatments (NATs), including chemotherapy and chemoradiotherapy, has also been accumulating. Recent results from prospective studies and meta-analyses suggest that NATs may be beneficial not only for borderline resectable PDAC, but also for resectable PDAC, by increasing the likelihood of successful R0 resection, decreasing the likelihood of the development of lymph node metastasis, and improving recurrence-free and overall survival. In addition, response to NAT may be informative for predicting the clinical course after preoperative NAT followed by surgery; in this way, the postoperative treatment strategy can be revised based on the effect of NAT and the post-neoadjuvant therapy/surgery histopathological findings. On the other hand, the response to NAT and AC is also influenced by the tumor biology and the patient's immune/nutritional status; therefore, planning of the treatment strategy and meticulous management of NAT, surgery, and AC is required on a patient-by-patient basis. Our experience of using gemcitabine plus S-1 showed that this NAT regimen achieved tumor shrinkage and decreased the levels of tumor markers but failed to provide a survival benefit. Our results also suggested that response/adverse events to NAT may be predictive of the efficacy of AC, as well as survival outcomes.

Comparison of the upfront surgery and neoadjuvant therapy in resectable and borderline resectable pancreatic cancer: an updated systematic review and meta-analysis

Pancreatic cancer is a malignant disease with a dismal prognosis. While neoadjuvant therapy has shown promise in the treatment of pancreatic cancer, its role remains a subject of controversy among physicians. We aimed to evaluate the benefits of neoadjuvant therapy in patients with resectable and borderline resectable pancreatic cancer. Eligible studies were identified from MEDLINE, Embase, Cochrane Library, and Web of Science. Studies comparing neoadjuvant therapy with upfront surgery (with or without adjuvant therapy) in resectable and borderline resectable pancreatic cancer were included. The primary endpoint assessed was overall survival. A total of 10,022 studies were identified, and the meta-analysis finally enrolled 50 revealed studies. The meta-analysis suggested that neoadjuvant therapy significantly improved the overall survival (HR 0.74, p < 0.001) and recurrence-free survival (HR 0.75, p = 0.006) compared to the upfront surgery approach. Furthermore, neoadjuvant therapy leads to favorable postoperative outcomes, with an enhanced R0 resection rate (OR 1.90, p < 0.001) and reduced lymph node metastasis (OR 0.36, p < 0.001) and perineural invasion (OR 0.42, p < 0.001), although it is associated with a reduced resection rate (OR 0.42, p < 0.001). In addition, patients treated with neoadjuvant therapy experience superior survival benefits compared to those undergoing adjuvant therapy (HR 0.87, p = 0.019). These results are further corroborated by the subgroup analysis of randomized controlled trials. Neoadjuvant therapy has the potential to provide survival benefits and improve postoperative long-term outcomes for patients with resectable and borderline resectable pancreatic cancer. However, to validate and reinforce these findings, further well-designed and large trials are required.

The benefits of neoadjuvant therapy for patients with resectable pancreatic cancer: an updated systematic review and meta-analysis

Neoadjuvant therapy (NAT) was effective in improving overall survival (OS) of borderline resectable pancreatic cancer. However, its application in resectable pancreatic cancer remains controversial. This study aimed to determine whether NAT has a greater advantage over conventional upfront surgery (US) in terms of resection rate, R0 resection rate, positive lymph node rate, and OS. We identified articles before October 7, 2022, by searching four electronic databases. The studies included in the meta-analysis all met the inclusion and exclusion criteria. The Newcastle-Ottawa scale was used to evaluate the quality of the articles. OS, DFS, resection rate, R0 resection rate and positive lymph nodes rate were extracted. Odds ratio (OR), hazard ratio (HR) and 95% confidence intervals (CI) were calculated, and sensitivity analysis and publication bias were used to assess the sources of heterogeneity. In total, 24 studies, involving 1384 (35.66%) patients assigned to NAT and 2497 (64.43%) patients assigned to US, were included in the analysis. NAT could effectively prolong OS (HR 0.73, 95% CI 0.65-0.82, P < 0.001) and DFS (HR 0.72, 95% CI 0.62-0.84, P < 0.001). Subgroup analysis results of 6 randomized controlled trials (RCTs) also showed that RPC patients could benefit from NAT in the long term (HR 0.72, 95% CI 0.58-0.90, P = 0.003). NAT decreased resection rate (OR 0.43, 95% CI 0.33-0.55, P < 0.001), but was associated with increased R0 resection rate (OR 2.05, 95% CI 1.47-2.88, P < 0.001) and decreased positive lymph node rate (OR 0.38, 95% CI 0.27-0.52, P < 0.001). Although the application of NAT increases the risk of patients not being able to undergo surgical resection, it can prolong the OS and delay tumor progression in RPC. Therefore, we still expect larger and higher-quality RCTs to confirm the effectiveness of NAT.

Preoperative treatments in borderline resectable and locally advanced pancreatic cancer: current evidence and new perspectives

Surgery is the only curative treatment for non-metastatic pancreatic adenocarcinoma, but less than 20% of patients present a resectable disease at diagnosis. Treatment strategies and disease definition for borderline resectable pancreatic cancer (BRPC) and locally advanced pancreatic cancer (LAPC) vary in the different cancer centres. Preoperative chemotherapy (CT) is the standard of care for both BRPC and LAPC patients, however literature data are still controversial concerning the type, dose and duration of the different CT regimens, as well as regarding the integration of radiotherapy (RT) or chemoradiation (CRT) in the therapeutic algorithm. In this unsettled debate, we aimed at focusing on the therapeutic regimens currently in use and relative literature data, to report international trials comparing the available therapeutic options or explore the introduction of new pharmacological agents, and to analyse possible new scenarios in microenvironment evaluation before and after neoadjuvant therapies or in patients' selection at a molecular level.

Comparison the efficacy and safety of different neoadjuvant regimens for resectable and borderline resectable pancreatic cancer: a systematic review and network meta-analysis

BACKGROUND

To date, the optimal recommended specific neoadjuvant regimens for resectable or borderline resectable pancreatic cancer (RPC or BRPC) remain an unanswered issue.

METHODS

We systematically searched the electronic databases to identify randomized controlled trials (RCTs) comparing different neoadjuvant therapy strategies for RPC or BRPC. The primary outcome was overall survival (OS). Comprehensive analyses and evaluations were performed using the single-arm, paired, and network meta-analyses.

RESULTS

Twelve RCTs involving 1279 patients with RPC or BRPC were enrolled. The paired meta-analysis showed that neoadjuvant therapy improved OS for both RPC (hazard ratio (HR) 0.69, 95% c.i. 0.54 to 0.87) and BRPC (HR 0.60, 0.42 to 0.86) compared with upfront surgery (UP-S). Neoadjuvant chemotherapy (NAC) also improved OS for both RPC (HR 0.63, 0.47 to 0.85) and BRPC (HR 0.44, 0.27 to 0.71), while neoadjuvant chemoradiotherapy (NACR) improved OS only for BRPC (HR 0.68, 0.52 to 0.89) and not for RPC (HR 0.79, 0.54 to 1.16). Network meta-analysis found that NAC was superior to NACR in OS for RPC/BRPC (HR 0.58, 0.37 to 0.90). Neoadjuvant chemotherapy based on modified fluorouracil/folinic acid/irinotecan/oxaliplatin (NAC-mFFX) and neoadjuvant chemotherapy based on abraxane/gemcitabine (NAC-AG) ranked first and second in OS for RPC/BRPC.

CONCLUSIONS

Both RPC and BRPC could obtain OS benefits from neoadjuvant therapy compared with UP-S, and NAC improved OS both in RPC and BRPC while NACR only improved OS in BRPC. Furthermore, NAC was superior to NACR, and NAC-mFFX and NAC-AG might be recommended sequentially as the best neoadjuvant therapy strategies.

Neoadjuvant Treatment in Resectable Pancreatic Cancer. Is It Time for Pushing on It?

Pancreatic resection still represents the only curative option for patients affected by pancreatic ductal adenocarcinoma (PDAC). However, the association with modern chemotherapy regimens is a key factor in improving the inauspicious oncological outcome. The benefit of neoadjuvant treatment (NAT) for borderline resectable/locally advanced PDAC has been demonstrated; this evidence raises the question of whether even resectable PDAC should undergo NAT rather than upfront surgery. NAT may avoid futile surgery because of undetected distant metastases or aggressive tumor biology, providing more effective systemic control of the disease, which is hampered when adjuvant chemotherapy is delayed or precluded. However, recent data show controversial results regarding the efficacy and safety of NAT in resectable PDAC compared to upfront surgery. Although several prospective studies and meta-analyses indicate better oncologic outcomes after NAT, there are some biases, such as the methodological approaches used to capture the events of interest, which could make these results hardly reproducible. For instance, per-protocol studies, considering only the postoperative outcomes, tend to overestimate the performance of NAT by excluding patients who will never be suitable for surgery due to the development of chemotoxicity or tumor progression. To draw reliable conclusions, the studies should capture the events of interest of both strategies (NAT/upfront surgery) from the time of allocation to a specific treatment in an intention-to-treat fashion. This critical review highlights the current literature data concerning the use of NAT in resectable PDAC, summarizing the results of high-quality studies and focusing on the methodological issues of the most recent pieces of evidence.