Copenhagen, Denmark
Onsite/Online

ESTRO 2022

Session Item

Saturday
May 07
10:30 - 11:30
Room D1
Upper GI
Jean-Emmanuel Bibault, France;
Thomas Brunner, Austria
Proffered Papers
Clinical
11:10 - 11:20
Prognostic factors for isolated local recurrence after resection of pancreatic ductal adenocarcinoma
Iris van Goor, The Netherlands
OC-0111

Abstract

Prognostic factors for isolated local recurrence after resection of pancreatic ductal adenocarcinoma
Authors:

Iris van Goor1,2, Anne Nagelhout2, Marc Besselink3, Bert Bonsing4, Koop Bosscha5, Lodewijk Brosens6, Olivier Busch3, Geert Cirkel7, Ronald van Dam8, Sebastiaan Festen9, Bas Groot Koerkamp10, Erwin van der Harst11, Ignace de Hingh12, Geert Kazemier13, Gert Meijer1, Vincent de Meijer14, Vincent Nieuwenhuijs15, Daphne Roos16, Jennifer Schreinemakers17, Martijn Stommel18, Robert Verdonk19, Hjalmar van Santvoort2, Quintus Molenaar2, Lois Daamen20, Martijn Intven1

1UMC Utrecht Cancer Center, Radiation Oncology, Utrecht, The Netherlands; 2Regional Academic Cancer Center Utrecht, UMC Utrecht Cancer Center & St. Antonius Hospital Nieuwegein, Surgery, Utrecht, The Netherlands; 3Cancer Center Amsterdam, Amsterdam UMC, University of Amsterdam, Surgery, Amsterdam, The Netherlands; 4Leiden UMC, Surgery, Leiden, The Netherlands; 5Jeroen Bosch Hospital, Surgery, Den Bosch, The Netherlands; 6Regional Academic Cancer Center Utrecht, UMC Utrecht Cancer Center & St. Antonius Hospital Nieuwegein, Pathology, Utrecht, The Netherlands; 7Regional Academic Cancer Center Utrecht, UMC Utrecht Cancer Center & Meander Medical Center Amersfoort, Medical Oncology, Utrecht, The Netherlands; 8Maastricht UMC+, Surgery, Maastricht, The Netherlands; 9OLVG, Surgery, Amsterdam, The Netherlands; 10Erasmus MC, Surgery, Rotterdam, The Netherlands; 11Maasstad Hospital, Surgery, Rotterdam, The Netherlands; 12Catharina Hospital, Surgery, Eindhoven, The Netherlands; 13Cancer Center Amsterdam, Amsterdam UMC, Vrije Universiteit, Surgery, Amsterdam, The Netherlands; 14UMC Groningen, University of Groningen, Surgery, Groningen, The Netherlands; 15Isala, Surgery, Zwolle, The Netherlands; 16Reinier de Graaf Gasthuis, Surgery, Delft, The Netherlands; 17Amphia Hospital, Surgery, Breda, The Netherlands; 18Radboud UMC, Surgery, Nijmegen, The Netherlands; 19Regional Academic Cancer Center Utrecht, UMC Utrecht Cancer Center & St. Antonius Hospital Nieuwegein, Gastroenterology, Utrecht, The Netherlands; 20UMC Utrecht, Imaging, Utrecht, The Netherlands

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Purpose or Objective
About 20% of patients develop isolated local recurrence (ILR) within a median interval of 12 months after pancreatic ductal adenocarcinoma (PDAC) resection. Stereotactic body radiation therapy might improve survival and quality of life in these patients. To start treatment as early as possible, patients with a high risk of developing ILR should be identified. However, little is known about the risk factors for ILR. In this study, we aimed to identify predictive factors for ILR.
Material and Methods

This national cohort study was conducted among all patients who underwent PDAC resection in the Netherlands between 2014-2019. Patients were excluded in case of complication-related mortality within 90 days after resection, and macroscopic irradical resection. Furthermore, patients were also excluded in case of recurrence with unknown location. Baseline and perioperative data were collected from the mandatory, prospective Dutch Pancreatic Cancer Audit. Additional data on follow-up and survival was collected from the patients’ records.

Patients were divided into two groups based on their initial recurrence location: ILR or distant metastases (whether or not combined with synchronous local recurrence). Patients with distant metastases were censored at date of recurrence diagnosis. Patients without disease recurrence were censored at date of last follow-up. Missing data was considered missing at random and handled using multiple imputation with the iterative Markov chain Monte Carlo method. Univariable and multivariable Cox proportional hazard analysis was performed to identify prognostic factors for ILR and Akaike’s information criterion was used to select the best model. Survival was estimated and compared using Kaplan-Meier curves and log-rank test.
Results

A total of 1355 patients with a median follow-up of 33 (IQR 21–54) months were analysed. 957 patients (70%) developed disease recurrence. Among these patients, 201 patients (21%) presented themselves with ILR within a median recurrence-free interval of 14 (IQR 10–23) months. Their median overall survival (mOS) was 25 (IQR 15–35) months, compared to a mOS of 16 (IQR 10–26) months in patients who had distant metastases at initial presentation (Figure 1).

The best predictive model included all significant variables and had an area under the curve of 0.65. Factors associated with ILR were vascular resection (HR 1.70 [95%CI 1.26–2.29]; p <0.001), lymph vascular invasion (HR 0.73 [95%CI 0.54–0.98]; p 0.04), perineural invasion (HR 1.68 [95%CI 1.12–2.53]; p 0.01), lymph node status N2 (HR 1.69 [95%CI 1.13–2.52]; p 0.01) compared to N0, resection margin status R1 <1 mm (HR 1.65 [95%CI 1.23–2.22]; p <0.001), and adjuvant chemotherapy (HR  0.69 [95%CI 0.51–0.93]; p 0.02). Results are shown in Table 1.
Conclusion

In this nationwide cohort, predictive factors for ILR are vascular resection, absence of lymph vascular invasion, perineural invasion, N2 lymph node status, R1 resection margin status, and omission of adjuvant chemotherapy.