Efficacy and safety of 3D printing coplanar template-assisted iodine-125 seed implantation as palliative treatment for inoperable pancreatic cancer

Purpose
To investigate clinical efficacy and safety of 3D printing coplanar template-assisted iodine-125 (125I) seed implantation as a palliative treatment for inoperable pancreatic cancer.

Material and methods
Consecutive 28 patients (16 males and 12 females, median age of 64 years) with histologically diagnosed pancreatic cancer who underwent 3D printing coplanar template-assisted 125I seed implantation between June 2016 and May 2019 were analyzed. Among these 28 patients, 9 (32.1%) and 19 (67.9%) patients were presenting with tumor node metastasis (TNM) stage IIB and stage III cancer, respectively. Seed implantation was conducted for pain palliation intent in 25 patients and recurrent cancer after radiotherapy in 3 patients.

Results
No significant differences were found between pre-planned and post-operative dosimetric parameters, involving D90, D100, V90, V100, V150, conformity index, external index, and homogeneity index (all p > 0.05). Two months after implantation, pain relief rate was 76% (19/25) for pain patients. Overall tumor response rate (complete response + partial response) was 60.7% (complete response 0 patients, partial response 17 patients, stable disease 8 patients, and progressive disease 3 patients). Median survival was 10.5 months and estimated 1-year survival rate was 26.7%. Only one patient presented with a slightly upper gastro-intestinal hemorrhage, and another patient suffered from incomplete intestinal obstruction soon after implantation, both recovered after conservative medical treatment without a prolonged hospital stay. No major complication was observed.

Conclusions
3D printing coplanar template-assisted 125I seed implantation appears to be safe and effective palliative treatment for inoperable pancreatic cancer with favorable clinical outcomes.