Isolated Pancreatic Head Resection and Duodenectomy for GIST

Patient 63 years man without complicated medical history. He has pain in the epigastric area for 3-4 months. CT has found a tumor in the field of Treiz ligament and was radiologically evaluated more likely as non-epithelial. Biopsy was problematic according to this localization and we decided to perform surgery.
Intraoperatively we repeatedly sent material for cytology and histological examinations. The precise answer was not received, however, pathologists are increasingly inclined to diagnosis of non-epithelial malignant tumor.
As you can see in video the tumor localization was in the primary departments of the small intestine mesentery. Tumor has invasion in the pancreatic tissue and duodenal wall in its horizontal part. Superior Mesenteric vessels were free but first arterial and venous branches of jejunum were in tumor.
So, during operation I had most probable diagnosis was non-epithelial tumor. In this situation, I have decided to perform the isolated pancreatic resection (resection of processus uncinatus) and duodenectomy.
Urgent biopsy resection wounds showed the absence of tumor cells. In postoperative period we had no complications.
It is very interesting to hear your opinion if my surgical tactics was right. I would like to ask you a few questions.

1. Was the resection sufficient, if it is cancer of the pancreas , if resection line has no tumor cells?
2. What would be your strategy in this case ?
3. What might we do further for this patient? I am thinking about pylorus preserving PDE in case of recurrence.

N.B. I received reply from pathologist during posting this video. I typed this message without knowing the result. The final pathological conclusion - GIST

Video by Ilya Gotsadze (M.D., Ph.D.)