Analysis of cancer outcomes after desensitization protocols in patients with metastatic disease

Cancer chemotherapy and targeted therapy agents carry a potential risk for sensitization and induction of hypersensitivity reactions (HSR). It is widely unknown if patients who had drug reactions and underwent desensitization have different cancer outcomes, since the drug infusion time is largely extended. With this study we aim to describe patterns of HSR and overall survival (OS) rates for patients with metastatic cancer undergoing desensitization. This is a single center retrospective observational cohort study. Primary endpoint was OS. All patients with stage IV colorectal (CRC), breast (BC) and ovarian cancer (OC) undergoing desensitization from 2008 to 2013 at our institution were included. All patients with mild to severe HSR (Brown's classification) were desensitized at the Immunoallergology Unit using a 12-step protocol (6-hour infusion). Clinicopathological characteristics were tabulated according to type of primary. Proportion of patients alive at time points were obtained. Time to event outcomes were analyzed using Kaplan-Meier methods. 50 patients were included (14 BC, 17 CRC, 19 OC), 38 female and 12 male, the majority 50 years or older (n = 36, 72%) and with good performance status (Eastern Cooperative Oncology Group grade ≤ 1 in 94.6%, n = 35). Median follow-up time from diagnosis of metastatic disease was 40 months for BC (interquartile range [IQR] 31.3-67.8), 41.8 months for CRC (IQR 29.3-68.1) and 33.3 months for OC (IQR 25.7-56.9). Implicated agents were platinum salts (n = 32), taxanes (n = 15) and targeted therapy agents (n = 3), used mostly after second line of therapy (n = 29, 58%). Nine patients had mild HSRs (18%), 23 moderate (46%) and 18 had severe HSRs (36%). A total of 284 desensitizations were performed (median of 5 cycles/patient). Median OS was 47.3 months for BC (11 events, IQR 31.9-92.1), 37.2 months for CC (13 events, IQR 28.3—78.6) and 33.3 months for OC (16 events, IQR 25.7-56.9). In the absence of prospective randomized studies, for ethical reasons, the experience of our institution suggests that administration of cancer therapy through desensitization protocols is feasible and patients' outcomes seem adequate for the overall anticipated outcomes in this group of patients.