EUS-RFA Improves Survival in Unresectable Small Pancreatic Ductal Adenocarcinoma

Survival outcomes were improved with endoscopic ultrasound (EUS)-guided radiofrequency ablation (RFA) plus chemotherapy for patients with unresectable small primary pancreatic ductal adenocarcinoma (PDAC). These study results were presented at the American College of Gastroenterology (ACG) 2022 Annual Meeting, held from October 21 to 26, 2022, in Charlotte, North Carolina, and virtually.

Some small PDAC can not be cured with surgery due to blood vessel involvement or distant metastasis. The current standard of treatment for unresectable small PDAC is systemic therapy. Investigators from Chulalongkorn University in Thailand hypothesized that survival outcomes may be improved with the addition of EUS-RFA to systemic therapy.

To test their hypothesis, patients with unresectable PDAC with primary tumors less than or equal to 4 cm who underwent EUS-RFA plus chemotherapy (n=11) between 2017 and 2022 were compared with a matched historical cohort of patients who received chemotherapy without EUS-RFA (n=35). To balance for cohort differences, a weighting approach was used to compare 12-month survival outcomes. The EUS-RFA intervention was delivered using a 19-gauge RFA needle using a VIVA combo RF system with 50 W energy and 100 W impedance.

The patients in the intervention and control cohorts had a mean age of 63±13.5 and 69±8.1 years; 81.8% and 62.9% were women; Charleston Comorbidity Index (CCI) was 2.91±2.4 and 2.89±1.3; tumor diameters were 3.25±0.51 and 3.10±0.58 cm; 45.5% and 37.1% were receiving second-line therapy; and 54.6% and 68.5% had stage III disease, respectively.

In patients PDAC with primary lesions ≤4 cm that cannot be cured by surgery, EUS-RFA combined with chemotherapy resulted in improved survival and progression free survival with minimal adverse events.

Median weighted survival rates were 14 months for the EUS-RFA and 6.1 months for the chemotherapy alone cohorts. At both 6 (73% vs 69%) and 12 (64% vs 17%) months, the EUS-RFA recipients had a higher survival probability than the systemic therapy recipients, respectively.

Together, these data indicated that EUS-RFA was associated with decreased risk for mortality compared with the chemotherapy cohort (hazard ratio [HR], 0.38; 95% CI, 0.17-0.84; P =.016).

Similarly, the median time to progression was 6.1 months for the EUS-RFA and 3.9 months for the chemotherapy alone cohorts. At both 6 (55% vs 28%) and 12 (36% vs 4%) months the EUS-RFA recipients had a higher progression-free survival probability than the systemic therapy recipients, respectively.

However, EUS-RFA was not associated with decreased risk for progression compared with the chemotherapy cohort (HR, 0.57; 95% CI, 0.36-1.26; P =.16).

The most common safety signal of EUS-RFA was mild abdominal pain, reported by 8.3% of patients.

The major limitation of this study was the small sample size. These findings should be confirmed among a larger group of patients.

“In patients PDAC with primary lesions ≤4 cm that cannot be cured by surgery, EUS-RFA combined with chemotherapy resulted in improved survival and progression free survival with minimal adverse events,” the study authors wrote.

References:

Kongkam P, Tantitanawat K, Lopimpisuth C, et al. High 1-year survival rate of unresectable pancreatic cancer size smaller than 4 cm in diameter treated with concurrent EUS-RFA: an average treatment effect on the treated weighted survival analysis. Abstract presented at: ACG 2022 Annual Meeting; October 21-26, 2022; Charlotte, NC. Abstract 5.