SAN FRANCISCO – Bursectomy was not found to be superior to omentectomy for improving survival in patients with subserosal/serosal gastric cancer in a Japanese randomized phase III study.
The procedure – the dissection of the peritoneal lining covering the pancreas and anterior plane of the transverse mesocolon to prevent peritoneal metastasis – was common worldwide and considered standard in Japan from the 1950s until the mid-1990s, but was replaced by omentectomy following publication of reports questioning its value, according to Masanori Terashima, MD, of Shizuoka Cancer Center, Nagaizumi, Japan.
However, interest in bursectomy was rekindled when a 2012 noninferiority phase II study suggested that bursectomy may improve survival; the authors concluded that it should not be abandoned as a futile procedure until more definitive data could be obtained (Gastric Cancer. 2012;15[1]:42-8).
“So based on this result, [Japanese Clinical Oncology Group] conducted a large-scale randomized phase III trial [JCOG1001] to evaluate the efficacy of bursectomy. The objective of this study was to confirm the superiority of bursectomy for clinical T3 or clinical T4a gastric cancer patients in terms of overall survival,” Dr. Terashima said at the symposium, sponsored by ASCO, ASTRO, the American Gastroenterological Association, and Society of Surgical Oncology.
At a planned interim analysis when 522 patients had been enrolled, the Data and Safety Monitoring Committee approved continued enrollment. However, at a second interim analysis when 54% of expected events had been observed, the committee recommended early release of the survival results because “there was little possibility of demonstration of the superiority of bursectomy,” he said.
Overall 3-year survival was 83.3% among 601 patients in the bursectomy arm, compared with 86% in 600 patients in the nonbursectomy arm (hazard ratio, 1.07). The predictive probability of superiority of bursectomy was 12.7%.
Study subjects were adults aged 20-80 years (median of 65-66 years) with histologically proven adenocarcinoma of the stomach and clinical T3 or T4 disease. They enrolled from 57 institutions and were intraoperatively randomized to the bursectomy or nonbursectomy arm after confirmation of tumor stage. All received adjuvant chemotherapy with S-1 for 1 year for pathologic stage II/III disease.
Patients with bulky nodal metastases, Borrmann type 4 and 8 cm or larger Borrmann type 3 tumors were excluded, as their poor prognosis made them candidates for other clinical trials, Dr. Terashima said.
Patients’ background and operative procedures were well balanced between the arms, he noted.
For those in the bursectomy group, operation time was longer (median, 254 vs. 222 minutes), and blood loss was larger (330 vs. 230 mL), although the incidence of blood transfusion was not significantly different between the groups (4.5% vs. 4.8%).
The incidence of grade 3 or higher complications was slightly higher in the bursectomy arm (13.3% vs. 11.6%). This was due largely to the incidence of pancreatic fistulas, which was nearly double in the bursectomy arm (4.8% vs. 2.5% ).
Mortality was “quite low” in both groups (0.2 vs. 0.8%).
“There was no significant difference in overall survival between the arms. Bursectomy seemed to be a bit inferior to the nonbursectomy arm. Relapse-free survival also demonstrated no significant difference between the arms. Again, bursectomy seemed to be a bit worse than nonbursectomy,” he said.
The most common site of recurrence for all patient was the peritoneum, with 63 and 56 patients in the bursectomy and nonbursectomy arms, respectively, experiencing peritoneal recurrence.
“We could not detect any subgroup who may have a benefit from bursectomy,” Dr. Terashima said.
“Bursectomy is not recommended as a standard treatment for clinical T3 or clinical T4 gastric cancer, while complete omentectomy remains a part of standard procedure,” he concluded.
Dr. Terashima reported receiving honoraria, and/or research funding from Chugai Pharma, Eisai; Lilly, Otsuka, Taiho Pharmaceutical, Takeda, and Yakult Honsha.