Borderline resectable pancreatic cancer: Certainties and controversies

Table 1 Criteria of Borderline Resectability according to MD Anderson Cancer Center, AHPBA/SSAT/SSO, National Comprehensive Cancer Network, Japan Pancreas Society classification (7^th edition)

MD Anderson Cancer Center	AHPBA/SSAT/SSO	National Comprehensive Cancer Network 2021	Japan Pancreas Society classification (7th edition)
Anatomical	Anatomical	Anatomical	Anatomical
Arterial: SMA/CA: Tumour abutment ≤ 180° of the circumference of the artery; periarterial stranding and tumour points of contact forming a convexity against the vessel improve chances of resection; CHA: Short-segment incasement/abutment (typically at the GDA origin); the surgeon should be prepared for vascular resection/interposition grafting.	Arterial: GDA: Encasement up to the hepatic artery with either short segment encasement or direct abutment of the hepatic artery, without extension to the celiac axis; SMA: tumour abutment < 180° of the circumference of the vessel wall.	Arterial: Pancreatic head/uncinate process: SMA: Solid tumour contact ≤ 180°; CHA: Solid tumour contact without extension to CA or hepatic artery bifurcation allowing for safe and complete resection and reconstruction; Solid tumour contact with variant arterial anatomy (e.g., accessory right hepatic artery, replaced right hepatic artery, replaced CHA, and the origin of replaced or accessory artery). Pancreatic body/tail: CA: Solid tumour contact < 180°; CA: Solid tumour contact ≥ 180° without involvement of the aorta and with intact and uninvolved gastroduodenal artery thereby permitting a modified Appleby procedure1.	Arterial: SMA/CA: Tumour contact or invasion ≤ 180° without showing stenosis or deformity; CHA: Tumour contact or invasion without showing tumour contact or invasion of the PHA and/or CA.
Venous: SMV/PV: Short-segment occlusion with suitable vessel for reconstruction above and below.	Venous: SMV/PV: Venous involvement demonstrating tumour abutment with or without impingement and narrowing of the lumen; SMV/PV: Encasement but without encasement of the nearby arteries; SMV/PV: Short segment venous occlusion resulting from either tumour thrombus or encasement but with suitable vessel proximal and distal to the area of vessel involvement, allowing for safe resection and reconstruction.	Venous: SMV/PV: Solid tumour contact ≥ 180°, contact of < 180° with contour irregularity of the vein or thrombosis of the vein but with suitable vessel proximal and distal to the site of involvement allowing for safe and complete resection and vein reconstruction. IVC: solid tumour contact.	Arterial: SMA/CA: Tumour contact or invasion ≤ 180° without showing stenosis or deformity; CHA: Tumour contact or invasion without showing tumour contact or invasion of the PHA and/or CA.
Biological: CT findings suspicious, but not diagnostic of metastatic disease; Histologically confirmed N1 disease.	-	-	-
Conditional: ECOG performance status ≥ 3.	-	-	-

¹Some panel members prefer these criteria to be in the locally advanced category.

SMA: Superior mesenteric artery; CHA: Common hepatic artery; SMV: Superior mesenteric vein; PV: Portal vein; GDA: Gastroduodenal artery; CA: Celiac artery; CT: Computed tomography; ECOG: Electrocorticography; IVC: Inferior vena cava; PHA: Polyhydroxyalkanoates.

Table 2 Systematic reviews and meta-analysis on neoadjuvant treatment for borderline resectable pancreatic ductal adenocarcinoma

Ref.	N° of studies	N° of included patients	Tumour	NAT regimen	RT	Included studies
Gillen et al[20], 2010	111	4394	R-PDAC, BR-PDAC, LA-PDAC	Gem, 5-FU, 5-FU + Mytomin C, 5-FU + Ox, Gem + Ox, taxanes	+/-	Prospective, retrospective
Tang et al[15], 2015	18	9591	BR-PDAC	FOLFIRINOX, Cap, Gem, Gem + Docetaxel, Gem + S1, 5-FU + Pac + Gem + Cap, Gem + Ox	+/-	Prospective
Dhir et al[17], 2017	96	5520	R-PDAC, BR-PDAC, LA-PDAC	FOLFIRINOX, Cap, Gem, 5-FU, Gem + Docetaxel, Gem + S1, Pac + Gem + Cap, Gem + Ox, Gem + Pac	+/-	Prospective, retrospective, RCT
Versteijne et al[19], 2018	38	3484, 17381	R-PDAC, BR-PDAC	NR	+/-	Prospective, retrospective, RCT
Pan et al[21], 2019	17	2286	R-PDAC, BR-PDAC	5-FU + Cis, Cap, 5-FU, Gem, Gem + Cap, Gem + Cis, Gem + S1, Gem + Pac	+/-	Prospective, retrospective, RCT
Cloyd et al[22], 2020	6	850, 4111	R-PDAC, BR-PDAC	Gem, Gem+S1	+/-	RCT

¹Patients who underwent NAT.

BR: Borderline resectable; LA: Locally advanced; PDAC: Pancreatic ductal adenocarcinoma; NR: Not reported; Cap: Capecitabine; Gem: Gemcitabine; 5-FU: 5-fluorouracil; Pac: Paclitaxel; Ox: Oxaliplatin; Cis: Cisplatin; RCT: Randomized controlled trial.