MONTREAL – For individuals with stage III pancreatic cancer, neoadjuvant therapy may improve survival, compared with surgery-first treatment. “This study supports, however does not prove, the hypothesis that early and continued control of occult metastatic disease prolongs survival in surgical patients,” said Dr. Christopher Shubert.
Dr. Shubert and his colleagues used an intention-to-treat (ITT) analysis to compare overall survival (OS) for 377 patients who were to receive neoadjuvant chemotherapy with 216 patients who received surgery first. Median OS for the neoadjuvant group was 20.7 months, compared with 13.7 months for the surgery-first group (log-rank P less than .0001).
This study was the first to utilize national data to look at how patients who received neoadjuvant chemotherapy for stage III pancreatic cancer fared, when compared with those treated with a surgery-first approach, Dr. Shubert, a general surgery resident at the Mayo Clinic in Rochester, Minn., said at the annual meeting of the Central Surgical Association.
Stage III pancreatic cancer (T4, any N, M0) means that the cancer has invaded the celiac trunk, or there is superior mesenteric artery involvement, he noted.
Using data from the National Cancer Database from 2002 to 2011, the investigators identified patients with clinical stage III pancreatic adenocarcinoma of the head or body of the pancreas. The ITT neoadjuvant therapy cohort included all patients whose treatment recommendations included curative-intent surgery and neoadjuvant chemotherapy, regardless of what therapies the patients received. The surgery-first cohort included those who were recommended to receive adjuvant therapy.
A total of 593 patients were identified, of whom 377 (63.5%) were in the neoadjuvant group. Of these, 104 (27.6%) were lost to presurgical attrition. The surgery-first group included 216 patients (36.3%), 30 (13.9%) of whom did not receive the intended adjuvant chemotherapy. Comparing the two ITT groups yielded an adjusted hazard ratio of 0.68 (P = .001).
A secondary aim of the study was to see which aspects of therapy, and which pathologic features, were associated with longer OS. The addition of postsurgical therapy was associated with additional survival benefit (31.6 vs. 22.6 months for no postsurgical therapy; HR, 0.60; P = .002). Node-negative and R0 status were both also significantly increased among those receiving neoadjuvant chemotherapy, and both disease characteristics were associated with increased OS, he reported.
Dr. Shubert said that study limitations included its review of a prospective database. Also, investigators could not determine the type or duration of chemotherapy; they also were unable to tell when systemic chemotherapy plus chemoradiation or just chemoradiation alone had been used. No recurrence data were available, and all cases were grouped under one procedure code, limiting information about vascular resections.
“Neoadjuvant therapy may offer survival advantages compared to a surgery-first approach,” said Dr. Shubert, and control of small occult metastases may be the mechanism behind this advantage. Still to be determined, however, are the optimal type, duration, and sequencing of neoadjuvant chemotherapy and chemoradiation, he said.
Dr. Shubert reported no relevant disclosures.
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