Patterns of Use of the Oncotype DX Breast Recurrence Score® Test in a Kurdish Population of Patients with Breast Cancer: A Multi-Institutional, Retrospective Study

Oncotype DX (ODX) is widely used to predict recurrence risk and guide treatment in early-stage, estrogen receptor-positive, HER2-negative breast cancer by analysing 21 genes to provide a recurrence score (RS). Validated in clinical trials, it is endorsed by major organizations like NCCN, ASCO, and ESMO. In the Kurdistan Region of Iraq, ODX is funded by the Cancer Patients' Support Fund (CPSF), but access remains inconsistent. This study aimed to investigate the patterns of Oncotype DX Breast Recurrence Score® test utilization in a Kurdish population of patients with breast cancer, highlighting challenges and opportunities for optimizing patient selection and clinical benefit while addressing financial considerations. This retrospective study in the Kurdistan region of Iraq (2018-2023) involved 300 patients with luminal-type early-stage breast cancer. Data on demographics, tumor characteristics, and Oncotype DX Recurrence Scores® were analyzed to assess test usage patterns. Descriptive statistics were applied, and ethical approval was obtained from all participating centers. The median age of patients was 52 years (range 26-87), with 98.3% being female. Mastectomies were performed in 36% of cases, while 59% had breast-conserving surgeries. Axillary node-positive disease was present in 2.4%, with a median of 6 lymph nodes resected. Most patients had unifocal (76.3%) disease, and invasive ductal carcinoma was the dominant histology (83%). Tumors were primarily grade II (62.9%), with lymphovascular invasion in 17.1% and perineural invasion in 16.1%. Recurrence scores (ORS) were low, intermediate, and high in 16.7%, 54.5%, and 23.4% of cases, respectively. This study provides key insights into breast cancer patients in the Kurdistan region, particularly regarding the use of the Oncotype DX Breast Recurrence Score® test. Most patients were female, with left-sided and invasive ductal carcinoma being more prevalent. The study highlights gaps in sentinel lymph node biopsy implementation and delays in test turnaround times due to healthcare infrastructure challenges.