Genomic testing in early breast cancer (EBC) for low middle income countries (LMIC): Is it worth the cost?

Abstract

e12521 Background: Chemotherapy is crucial for EBC management but has toxicities. Attempts are made to identify patients where chemotherapy can be safely skipped. Genomic testing offers advantage over clinico-pathological tools but given the cost, its utility in clinical practise, especially in LMIC remains questionable. Methods: 50 EBC patients who underwent risk stratification by oncotypeDX were retrospectively studied. Their clinico-pathological characteristics, Nottingham prognostic index (NPI) and PREDICT recommendation (v 2.1) were recorded. Tumor board(TB) made treatment recommendations based on age and histopathology, blinded to recurrence score(RS). The results were compared. Results: 32% patients were < 50 years, 68% were > 50 years. 32% and 68% patients were pre and post menopausal respectively. On pathological examination, T1, T2 & T3 comprised 26%, 70% and 4% respectively. 96% were node negative, 2% node positive, 2% had unknown nodal status. Tumors had Grade 1, 2 and 3 in 8%, 88% and 4% respectively. 4% had unknown estrogen receptor (ER), progesterone receptor (PR) score. ER and PR were low (Allred 3-5) in 2% and 12% respectively. NPI was low ( < 3.4) in 96% and intermediate (3.5- 5.4) in 4%. On PREDICT, all showed low benefit of chemotherapy ( < 3% at 10 years). TB prescribed chemotherapy in 58% and hormonal therapy (HT) in 42% patients. RS was low, intermediate and high in 66%, 26% and 8% patients respectively. Patients with low and high RS were supposed to receive HT and chemotherapy respectively. In the intermediate group, 4% patients were recommended HT as per age. 22% patients could not be assigned a treatment based on RS alone. In remaining 78%, TB’s decision matched RS recommendation in 38% (19) patients. In 2% (1), TB recommended HT while OncotypeDX showed high RS. In 38% (19) patients, TB recommended chemotherapy while OncotypeDX showed low RS. Despite all having low/intermediate NPI with < 3% chemotherapy benefit on PREDICT, 8% showed chemotherapy benefit on OncotypeDX. In 40%, OncotypeDX recommendation deferred from TB. In more than one third patients, when TB recommended chemotherapy, RS came low. In these patients we could avoid chemotherapy, saving ~900 USD treatment costs. As 68% patients were elderly ( > 50), genomic testing avoided chemotherapy in this subgroup, likely to suffer treatment toxicities. Conclusions: In LMIC where all patients don’t have access to hospitals with adequate infrastructure for chemotherapy administration, genomic testing has significant implications. We recommend using it more in clinical practise.