Is There any Survival Benefit of Maintenance Chemotherapy Following Adjuvant Chemotherapy in Patients with Resected Pancreatic Cancer Patients with Post-Surgery Elevated CA 19-9?

Background: Pancreatectomy offers only potential for cure but is only possible in a minority of patients. Even in those patients who receive adjuvant chemotherapy, majority of them succumb to death due to metastases. Radiation Therapy Oncology Group 9704 showed that post-surgery CA 19-9 levels are an important predictor of survival. European study group for pancreatic cancer-3 showed that completion of all 6 cycles of adjuvant chemotherapy was an independent prognostic factor. Any survival benefit of an intensified chemotherapy strategy has not been demonstrated in patients with persistently elevated CA 19-9 following surgery. The object of this study was to investigate any benefit of maintenance chemotherapy following adjuvant in these patients.

Methods: Twenty patients with R0 surgery of pancreatic cancer who received adjuvant chemotherapy with post-surgery elevated CA 19-9 but no radiographic evidence of cancer was identified from 2005-2017. Either biopsy or positron emission tomography scan determined recurrence of cancer. Efficacy endpoints including overall survival and disease-free survival were assessed.

Results: Maintenance and additional chemotherapeutic agents included 5-FU, capecitabine, platinum agents, irinotecan and nab-paclitaxel. CA 19-9 normalized in 3 patients while 22 persisted to be elevated or had further increase in the marker. Two patients underwent metastatectomy. Median disease-free survival was 14.5m (9-18), OS 29m (19-96) and OS rates were 80%, 50% at 1 and 2 years respectively.

Conclusions: We believe that the longer overall survival of our patients with elevated CA 19-9 post-surgery was due to maintenance and additional chemotherapy following planned 6-months of adjuvant therapy, close monitoring with monthly CA 19-9 and 3-monthly computed tomography scans. Our study also underlines importance of collecting pre-surgery CA 19-9 and complete staging including chest. Prospective study aiming to evaluate role of maintenance or intensified chemotherapy or targeted agents are indicated.