Abstract 3425
Background
Genetic variants of dihydropyrimidine dehydrogenase (DPYD) gene can result in varied enzymatic activity and potential toxicity when receiving 5-FU chemotherapy including treatment related death in up to 1% patients. Current international guidelines suggest an international rate of 3-5% albeit routine prospective pharmacogenomic testing is not currently recommended. However, in a genetically homogenous population such as Ireland, DPYD variant enrichment may support routine testing.
Methods
All patients receiving 5-FU based chemotherapy in South & South-West region of Ireland were prospectively tested from 01/09/2018 to present. The Viapath DPYD genotyping panel which interrogates for 5 variants was used. Toxicity type and grade for all patients were recorded (CTCAE v5.0).
Results
To date, 139 patients have been tested,50.4% male and 49.6% female, median age 63 years. The majority(59%) were being treated for colorectal cancer. Sixteen patients were found to be heterozygous carriers of a DYPD variant with one compound heterozygous variant identified i.e. an overall prevalence of 12 %. No homozygous carriers were identified. Grade ≥3 was observed in 33% DPYD variant carriers compared to 19% in DPYD wild type patients i.e. relative risk of grade ≥3 toxicity is 1.7, p = 0.17.Table:
648P
DPYD Variants | Prevalence % n = 139 | % Rate of ≥ G3 toxicity |
---|---|---|
7(5.0%) | 42% | |
c. 2846A>T | 1(0.7%) | n/a* |
c. 1905 + 1G>A | 3(2.2%) | 100% |
c. 1679T>G | 0 (0%) | n/a* |
c. 1601GA | 5 (3.6%) | 0% |
c. 1905 + 1G>A+c;1236G>A/Hapb3 compound heterozygous | 1(0.7%) | n/a* |
TOTAL:17 (12.2%) |
Conclusions
The study shows a higher than expected prevalence of DPYD variants of 12.2% compared to internationally reported 3-5%. Patients with DPYD variants c.1236G>A and c.1905+1G>A were particularly likely to develop Grade ≥ 3 toxicity. Prospective testing continues to assess the clinical relevance of individual variants in our population.
Legal entity responsible for the study: The authors.
Clinical trial identification
Editorial acknowledgement
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.
Resources from the same session
5747 - The routine use of sentinel lymph node biopsy in high risk DCIS lesions is not justified
Presenter: Fanny Preat
Session: Poster Display session 2
Resources:
Abstract
1837 - Oncological impact of re-excision for positive margin status after breast conserving surgery in invasive breast cancer
Presenter: Kenjiro Jimbo
Session: Poster Display session 2
Resources:
Abstract
4347 - Pneumonitis and fibrosis after breast cancer radiation.
Presenter: Jarle Karlsen
Session: Poster Display session 2
Resources:
Abstract
2280 - Prognosis of mastectomy with reconstruction after neoadjuvant chemotherapy: a nationwide study in Korean Breast Cancer Society
Presenter: Sungmin Park
Session: Poster Display session 2
Resources:
Abstract
804 - A negative prognosis of radiotherapy-induced lower lymphocyte to monocyte ratio in patients with breast cancer
Presenter: Chang-ik Yoon
Session: Poster Display session 2
Resources:
Abstract
2701 - Patient data to monitor clinical patterns in early and advanced breast cancer in Europe
Presenter: Francesco Giusti
Session: Poster Display session 2
Resources:
Abstract
1437 - A critical appraisal of quality indicators of breast cancer treatment in Belgium
Presenter: Didier Verhoeven
Session: Poster Display session 2
Resources:
Abstract
1534 - Predictors of adherence among post-menopausal women receiving adjuvant endocrine therapy for breast cancer in Ontario, Canada
Presenter: Phillip Blanchette
Session: Poster Display session 2
Resources:
Abstract
4363 - Evaluation of endocrine therapy and patients preferences in early breast cancer: results of Elena study
Presenter: Emilia Montagna
Session: Poster Display session 2
Resources:
Abstract
2679 - Baseline Quality of life (QoL) and chemotherapy related toxicities (CRT) in localized breast cancer (BC) patients (pts): the French multicentric prospective CANTO cohort study
Presenter: Idlir Licaj
Session: Poster Display session 2
Resources:
Abstract