ESTRO 37 Abstract book

ESTRO 37

S403

preoperative CRT and resection group (5-year OS 40.4% vs 68.1%, p<0.05; 5-year PFS 33.4% vs 66.1% (p<0.05).

Only LRR(%) n=36

Any MD(%) n=59

All recurrence(%) n=95

Site

Remnant pancreas

or

14(23.7) 1(2.8)

15(15.8)

tumor beds Superior mesenteric artery Celiac artery

Conclusion In potentially resectable gastric cancer, patients receive CRT can improve the possibility of R0 surgery. Patients who receive preoperative CRT and surgery have better OS than who receive CRT only. The patients with T4NxM0 gastric cancer who receive preoperative CRT and gastrectomy have better OS and PFS than the patients who receive gastrectomy and adjuvant CRT. Preoperative CRT may have influence on better prognosis. A large- sample randomized clinical trial is needed. PO-0779 local-regional failures after adjuvant chemotherapy for resectable pancreatic cancer S. Zhao 1 , C. Jiayi 1 1 Ruijin Hospital- Shanghai Jiaotong University School of Medicine, radiation oncology, Shanghai, China Purpose or Objective Contemporary trials evaluating adjuvant chemoradio- therapy for pancreatic ductal adenocarcinoma(PDAC) go after adjuvant chemotherapy instead of after surgery. However, the failure patterns after chemotherapy are still unclear. This study investigated the recurrence patterns after adjuvant chemotherapy, risk factors of only local-regional recurrence (LRR) and the high-risk involvement of sites to help radiation field design. Material and Methods Between January 2008 and February 2013, after curative resection and adjuvant chemotherapy, 114 patients with PDAC were given follow-up by CT scanning every 2-3 months. The development of a new low-density mass was considered as tumor recurrence. Recurrence patterns were classified as local, regional recurrence or distant metastasis (LR, RR, DM). Only LRR included LR and/or RR without DM, any DM included all patients with DM whether or not there is LR or RR. Results The mean follow-up interval was 63.5 months, 95 patients (83.3%) had developed recurrence. The median overall survival was 30.8 months (95% CI 26.8-34.9), while the median disease-free survival was 11.0 months (95% CI 9.0-13.0). The ratio of only LRR to any DM was 59/36. Surgery combined with vascular resection (OR 7.09, 95% CI: 1.45–34.64, P=0.02) and positive surgical margin status (OR 8.60, 95% CI: 1.73-42.69, P=0.01) were the risk factors associated with only LRR. Further investigation showed that in patients with only LRR, recurrence often presented in No.14p lymph nodes (30.5%), remnant pancreas or tumor beds (23.7%), No.16b1 lymph nodes (23.7%), celiac artery (CA) (22.0%), superior mesenteric artery (SMA) (22.0%), and No.9 (20.3%), 12p (15.3%), 14d (13.6%) lymph nodes.

13(22.0) 6(16.7)

19(20.0)

13(22.0) 4(11.1)

17(17.9)

Abdominal aorta

3(5.1)

1(2.8)

4(4.2)

Common hepatic artery

3(5.1)

0(0.0)

3(3.2)

Portal vein

3(5.1)

0(0.0)

3(3.2)

Inferior

vena

1(1.7)

0(0.0)

1(1.1)

cava Left

gastric

1(1.7)

0(0.0)

1(1.1)

artery

Splenic artery 1(1.7)

0(0.0)

1(1.1)

No.14p No.16b1

18(30.5) 6(16.7)

24(25.3)

14(23.7) 12(33.3) 26(27.4)

No.9

12(20.3) 6(16.7)

18(18.9) 16(16.8) 14(14.7) 10(10.5)

No.12p No.14d No.16a2

9(15.3) 8(13.6) 3(5.1) 2(3.4) 1(1.7) 1(1.7) 1(1.7) 1(1.7)

7(19.4) 6(16.7) 7(19.4) 2(5.6) 2(5.6) 2(5.6) 0(0.0) 0(0.0)

No.8a

4(4.2) 3(3.2) 3(3.2) 1(1.1)

No.7

No.12a No.15 No.16b2

1(1.1) Sites of recurrence (Lymph node station were defined by Japan Pancreas Society Classification of Nodes in Pancreatic Cancer) Conclusion The majority of patients with PDAC who underwent curative resection and adjuvant chemotherapy will eventually succumb to recurrence. The only LRR plays a predominant role among them. For patients with high-risk of only LRR, the optimal radiation field may optimize the implementation of adjuvant chemoradiotherapy. PO-0780 Radiochemotherapy in borderline re sectable and LAPC: report from three prospective phase II studies M. Fiore 1 , P. Trecca 1 , B. Floreno 1 , C. Rinaldi 1 , L.E. Trodella 1 , S. Valeri 1 , R. Coppola 1 , L. Trodella 1 , R.M. D'Angelillo 1 , S. Ramella 1 1 Campus Biomedico University, Department of Radiation Oncology, Roma, Italy