ESTRO 2024 - Abstract Book

S2243

Clinical - Upper GI

ESTRO 2024

Results:

The mean follow-up was 21 months (range, 10-34). The LAPC stage (TNM) was: IB (40%), IIB (20%), III (40%). All patients received chemotherapy (CHT) before PRT. Median GTV was 34.80 cc (9.81-70.72). Robustness was verified quantitatively by checking multiple data points on the DVH. In none of the patients there was the need to adapt the plan. Five patients were explored surgically, 3 patients had R0 resection, 1 patient had R1 resection, and 1 patient had exploration without resection. In all resected patients a major pathologic response (Le Scodan III, less than 10% vital tumor cells) was demonstrated. No G3 acute or late toxicity was reported, only G2 acute toxicity was observed in 3 patients (fatigue 1 patient, nausea/vomiting 1 patient and pain 1 patient) and during the follow up 2 patients experienced a G2 fatigue. Lymphocyte values before and after PRT were 1.63 x103/uL (0.86-3.12) and 1.17 x103/uL (0.41-1.92), respectively. At 1 month, the mean CA19.9 level decreased to 195 U/ml (21-529), compared to 217 U/ml (9.07-1373.7) before the start of PRT. One-year LR rates was 100%. One-year OS and FFDM were 36% and 14%, respectively.

Conclusion:

Hypo-fractionated, highly conformal PRT for LAPC with elective irradiation of lymph-nodes and neuro plexus was feasible and well-tolerated. Based on these preliminary findings, a prospective phase II trial (NCT05191940) has been initiated and it is currently enrolling patients.