The timing for adjuvant treatment following surgery for pancreatic cancer appears to have a sweet spot associated with the best survival outcomes, according to a study published in JAMA Network Open.

Researchers analyzed data from the National Cancer Database for 7,548 patients with stage I-II resected pancreatic cancer, 5,453 of whom had received adjuvant therapy and 2,095 who did not.

“While the benefit of adjuvant therapy to patients with resected pancreatic cancer is accepted, its optimal timing after surgery remains under investigation,” wrote Sung Jun Ma, MD, from the Roswell Park Comprehensive Cancer Center in Buffalo, N.Y., and coauthors.

After a median overall follow-up of 38.6 months, they found the lowest mortality risk was in the reference cohort of patients who started adjuvant therapy 28-59 days after surgery. In comparison, patients who received early adjuvant therapy – within 28 days of surgery – had a 17% higher mortality (P = .03), and those who received adjuvant therapy late – 59 days or more after surgery – had a 9% higher mortality (P = .008)

The overall survival rate at 2 years was 45.2% for the early adjuvant therapy cohort and 52.5% for the reference cohort.

Despite the higher mortality among the early adjuvant therapy cohort, patients treated with adjuvant therapy more than 12 weeks after surgery still showed improved survival, compared with patient treated with surgery alone, particular those with node-positive disease.

“To our knowledge, it is the first study to suggest that patients who commence adjuvant therapy within 28-59 days after primary surgical resection of pancreatic adenocarcinoma have improved survival outcomes compared with those who waited for more than 59 days,” the authors wrote. “However, patients who recover slowly from surgery may still benefit from delayed adjuvant therapy initiated more than 12 weeks after surgery.”

No treatment interactions were seen for other variables such as age, comorbidity score, tumor size, pathologic T stages, surgical margin, duration of postoperative inpatient admission, unplanned readmission within 30 days after surgery, and time from diagnosis to surgery.

The analysis also revealed that patients with a primary tumor at the pancreatic body and tail and those receiving multiagent chemotherapy or radiation therapy were less likely to receive delayed adjuvant therapy, However, older or black patients, those with lower income, with postoperative inpatient admission longer than 1 week or with unplanned readmission within 30 days after surgery were more likely to have delayed initiation of adjuvant therapy.

No conflicts of interest were reported.

SOURCE: Ma SJ et al. JAMA Netw Open. 2019 Aug 14. doi: 10.1001/jamanetworkopen.2019.9126.