P-188 Safety and efficacy of first-line gemcitabine plus nab-paclitaxel for elderly metastatic pancreatic cancer patients

Abstract

In total 14/506 (2.7%) patients had some form of DPD deficiency. 8/14 patients went on to have 5FU-based chemotherapy. Five opted against treatment and one patient was found to have an alternative diagnosis and treated with non-5FU-based chemotherapy. Both commercial testing kits give recommendations for treatment dosing. Of the 8 we treated: one received the recommended reduced dose, 5 commenced at a lower dose (due to safety concerns) and 2 patients received higher than the recommended dose (due to result not being available before treatment started). One of these 2 patients, was de-escalated to the recommended dose. The other had retrospective testing at representation with metastases; she had previously received 1 cycle of adjuvant treatment at 100% of the dose (before routine testing), developed significant toxicity and stopped after cycle 1. 5/8 (62%) patients who received 5FU-based chemotherapy experienced grade 3 toxicities leading to cessation of 5FU-based chemo in 4/5 of the cases. The most common toxicities were: diarrhoea (5 patients e 1 grade 3 toxicity), nausea (5 patients e no grade 3 toxicities), fatigue (4 patients e all grade 1) and mucositis (3 patients e 1 grade 3 toxicity). Conclusion:Treatment decisions in colorectal oncology are often complex and it is clear that the presence of DPD deficiency adds further complexity to these situations. Patients with DPD deficiency can experience severe side effects when treated with fluoropyrimidines and clinicians fear harming patients. Decisions based on results showing DPD deficiency varied widely in our centre and we clearly need structured guidelines on how these results should influence our treatment decisions so as not to harm patients, but also to not exclude patients from potentially beneficial treatments.Acknowledgement: With thanks to the colo-rectal team at Weston Park Hospital.Legal entity responsible for the study: The authors.Funding: Biomnis provided free testing during the first three months and Weston Park Cancer Charity contributed apporoximately £200 to the processing fees during the first three months of testing. abstracts Annals of Oncology Volume 31 -Issue S3 -2020 S151