Minimum and Optimal CA19-9 Response After Two Months Induction Chemotherapy in Patients With Locally Advanced Pancreatic Cancer: A Nationwide Multicenter Study

Pathological Complete Response in Patients With Resected Pancreatic Adenocarcinoma After Preoperative Chemotherapy

Importance

Preoperative chemo(radio)therapy is increasingly used in patients with localized pancreatic adenocarcinoma, leading to pathological complete response (pCR) in a small subset of patients. However, multicenter studies with in-depth data about pCR are lacking.

Objective

To investigate the incidence, outcome, and risk factors of pCR after preoperative chemo(radio)therapy.

Design, Setting, and Participants

This observational, international, multicenter cohort study assessed all consecutive patients with pathology-proven localized pancreatic adenocarcinoma who underwent resection after 2 or more cycles of chemotherapy (with or without radiotherapy) in 19 centers from 8 countries (January 1, 2010, to December 31, 2018). Data collection was performed from February 1, 2020, to April 30, 2022, and analyses from January 1, 2022, to December 31, 2023. Median follow-up was 19 months.

Exposures

Preoperative chemotherapy (with or without radiotherapy) followed by resection.

Main Outcomes and Measures

The incidence of pCR (defined as absence of vital tumor cells in the sampled pancreas specimen after resection), its association with OS from surgery, and factors associated with pCR. Factors associated with overall survival (OS) and pCR were investigated with Cox proportional hazards and logistic regression models, respectively.

Results

Overall, 1758 patients (mean [SD] age, 64 [9] years; 879 [50.0%] male) were studied. The rate of pCR was 4.8% (n = 85), and pCR was associated with OS (hazard ratio, 0.46; 95% CI, 0.26-0.83). The 1-, 3-, and 5-year OS rates were 95%, 82%, and 63% in patients with pCR vs 80%, 46%, and 30% in patients without pCR, respectively (P < .001). Factors associated with pCR included preoperative multiagent chemotherapy other than (m)FOLFIRINOX ([modified] leucovorin calcium [folinic acid], fluorouracil, irinotecan hydrochloride, and oxaliplatin) (odds ratio [OR], 0.48; 95% CI, 0.26-0.87), preoperative conventional radiotherapy (OR, 2.03; 95% CI, 1.00-4.10), preoperative stereotactic body radiotherapy (OR, 8.91; 95% CI, 4.17-19.05), radiologic response (OR, 13.00; 95% CI, 7.02-24.08), and normal(ized) serum carbohydrate antigen 19-9 after preoperative therapy (OR, 3.76; 95% CI, 1.79-7.89).

Conclusions and Relevance

This international, retrospective cohort study found that pCR occurred in 4.8% of patients with resected localized pancreatic adenocarcinoma after preoperative chemo(radio)therapy. Although pCR does not reflect cure, it is associated with improved OS, with a doubled 5-year OS of 63% compared with 30% in patients without pCR. Factors associated with pCR related to preoperative chemo(radio)therapy regimens and anatomical and biological disease response features may have implications for treatment strategies that require validation in prospective studies because they may not universally apply to all patients with pancreatic adenocarcinoma.

Nationwide Use and Outcome of Surgery for Locally Advanced Pancreatic Cancer Following Induction Chemotherapy

BACKGROUND

Several international high-volume centers have reported good outcomes after resection of locally advanced pancreatic cancer (LAPC) following chemo(radio)therapy, but it is unclear how this translates to nationwide clinical practice and outcome. This study aims to assess the nationwide use and outcome of resection of LAPC following induction chemo(radio)therapy.

PATIENTS AND METHODS

A multicenter retrospective study including all patients who underwent resection for LAPC following chemo(radio)therapy in all 16 Dutch pancreatic surgery centers (2014-2020), registered in the mandatory Dutch Pancreatic Cancer Audit. LAPC is defined as arterial involvement > 90° and/or portomesenteric venous > 270° involvement or occlusion.

RESULTS

Overall, 142 patients underwent resection for LAPC, of whom 34.5% met the 2022 National Comprehensive Cancer Network criteria. FOLFIRINOX was the most commonly (93.7%) used chemotherapy [median 5 cycles (IQR 4-8)]. Venous and arterial resections were performed in 51.4% and 14.8% of patients. Most resections (73.9%) were performed in high-volume centers (i.e., ≥ 60 pancreatoduodenectomies/year). Overall median volume of LAPC resections/center was 4 (IQR 1-7). In-hospital/30-day major morbidity was 37.3% and 90-day mortality was 4.2%. Median OS from diagnosis was 26 months (95% CI 23-28) and 5-year OS 18%. Surgery in high-volume centers [HR = 0.542 (95% CI 0.318-0.923)], ypN1-2 [HR = 3.141 (95% CI 1.886-5.234)], and major morbidity [HR = 2.031 (95% CI 1.272-3.244)] were associated with OS.

CONCLUSIONS

Resection of LAPC following chemo(radio)therapy is infrequently performed in the Netherlands, albeit with acceptable morbidity, mortality, and OS. Given these findings, a structured nationwide approach involving international centers of excellence would be needed to improve selection of patients with LAPC for surgical resection following induction therapy.

Currently Debated Topics on Surgical Treatment of Pancreatic Ductal Adenocarcinoma: A Narrative Review on Surgical Treatment of Borderline Resectable, Locally Advanced, and Synchronous or Metachronous Oligometastatic Tumor

BACKGROUND

Previously considered inoperable patients (borderline resectable, locally advanced, synchronous oligometastatic or metachronous pancreatic adenocarcinoma (PDAC)) are starting to become resectable thanks to advances in chemo/radiotherapy and the reduction in operative mortality.

METHODS

This narrative review presents a chosen literature selection, giving a picture of the current state of treatment of these patients.

RESULTS

Neoadjuvant therapy (NAT) is generally recognized as the treatment of choice before surgery. However, despite the increased efficacy, the best pathological response is still limited to 10.9-27.9% of patients. There are still limited data on the selection of possible NAT responders and how to diagnose non-responders early. Multidetector computed tomography has high sensitivity and low specificity in evaluating resectability after NAT, limiting the resection rate of resectable patients. Ca 19-9 and Positron emission tomography are giving promising results. The prediction of early recurrence after a radical resection of synchronous or metachronous metastatic PDAC, thus identifying patients with poor prognosis and saving them from a resection of little benefit, is still ongoing, although some promising data are available.

CONCLUSION

In conclusion, high-level evidence demonstrating the benefit of the surgical treatment of such patients is still lacking and should not be performed outside of high-volume centers with interdisciplinary teams of surgeons and oncologists.