Real-World Analysis of the Clinical and Economic Impact of the 21-Gene Recurrence Score (RS) in Invasive Lobular Early-Stage Breast Carcinoma in Ireland.

Background: This study, using real-world data, assesses the impact of RS testing on treatment pathways and the associated economic consequences of such testing. This paper pertains to lobular breast cancer. Methods: A retrospective, observational study was undertaken between 2011 and 2019 on a cross-section of hormone receptor-positive (HR+), HER2-negative, lymph node-negative, early-stage breast cancer patients. All patients had ILC and had RS testing in Ireland. The patient population is representative of the national population. Patients were classified as low (RS ≤ 25) or high (RS > 25) risk. Patients aged ≤50 were stratified as low (RS 0-15), intermediate (RS 16-25), or high risk (RS > 25). Results: A total of 168 patients were included, most of whom had grade 2 (G2) tumors (n = 154, 92%). Overall, 155 patients (92.3%) had low RS (≤25), 12 (7.1%) had high RS (>25), and 1 (0.6%) had unknown RS status. In 29 (17.5%) patients aged ≤50 at diagnosis, RS was ≤15 in 16 (55%), 16-20 in 6 (21%), 21-25 in 5 (17%), >25 in 1 (3.5%), and unknown in 1 (3.5%). Post RS testing, 126 patients (78%) had a change in chemotherapy recommendation; all to hormone therapy. In total, only 35 patients (22%) received chemotherapy. RS testing achieved a 75% reduction in chemotherapy use, resulting in savings of €921,543.84 in treatment costs, and net savings of €387,283.84. Conclusions: The use of this test resulted in a 75% reduction in chemotherapy and a significant cost savings in our publicly funded health system.

Breast screening in symptomatic women over 35 years of age: improvements in service efficiency.

INTRODUCTION: The rationalization of cancer services in Ireland saw all women with symptomatic breast problems referred to one of the eight regional cancer centers. A pilot triaging system was introduced in St Vincent's University Hospital to streamline these services. Women over 35 years who do not meet urgent referral criteria are referred for a mammogram prior to a clinic appointment ("image first"). The aim of this study was to retrospectively determine the recall rates, biopsy rates, and rate of breast cancer identification within this cohort of patients. This was compared to a screening population of patients. METHODS: Patients triaged into the "image first" group within a one-year period were identified. Results of the initial mammogram, further imaging and subsequent biopsies were recorded. Data relating to number of recalls, number of patients biopsied and number of cancers identified within the Merrion Unit of the National Breastcheck Screening Program was obtained for comparison. RESULTS: One thousand six hundred eighty-eight referrals were triaged as "image first" over this period. 185 (11%) of patients required a biopsy of an identified lesion. Breast cancer was diagnosed in 65 patients (3.9%). During the same study period, of the 42,099 women who were screened for breast cancer, 496 (1.8%) underwent biopsy and 267 (0.63%) were diagnosed with breast cancer. CONCLUSION: Image first patients, who represent a cohort of "symptomatic" non-urgent women, have a greater rate of breast cancer detection than an asymptomatic screening population. This may have an impact on the appropriate triaging of symptomatic women in a national cancer center.

Oncologic Outcomes After Treatment for MRI Occult Breast Cancer (pT0N+).

BACKGROUND: Studies assessing outcomes in occult breast cancer have often included women treated before the routine use of magnetic resonance imaging (MRI). This study examined outcomes for patients presenting with axillary adenopathy and no primary breast tumor detectable by MRI or other imaging methods. METHODS: All patients with axillary nodal metastases consistent with breast carcinoma and no breast primary tumor detectable by physical exam, mammography, or MRI treated between 1 January 1996 and 30 June 2011 were identified from an institutional database. Data were collected on local, regional, and distant recurrences. RESULTS: For the study, 38 patients were identified. Modified radical mastectomy (MRM) was performed for 13 of the patients, whereas 25 of the patients underwent axillary dissection (ALND) and whole-breast radiotherapy (WBRT). Most of the women had pathologic N1 disease [median number of positive nodes, 2 (MRM cohort) and 3 (ALND + WBRT cohort); p = 0.38]. All the patients received chemotherapy, and 30 (79%) of the 38 patients received an anthracycline and taxane. Regional nodal radiation was used for 60% of those with ALND + WBRT and for all 46% of the MRM patients who received chest wall radiotherapy. During a median follow-up period of 7 years, there were no nodal recurrences. Two patients treated with ALND + WBRT had in-breast recurrences, whereas none in the MRM group experienced a local recurrence. The proportion that experienced distant disease was similar between the MRM cohort (1 of 13) and the ALND + WBRT cohort (2 of 25). CONCLUSION: Breast cancer presenting as axillary adenopathy with no detectable primary tumor is rare. Breast conservation with WBRT is a viable option for patients with a diagnosis of occult breast cancer and a negative preoperative MRI.