RET fusions in a small subset of advanced colorectal cancers at risk of being neglected. (10th March 2018)

• Record Type: Journal Article
• Authors: Pietrantonio, F; Di Nicolantonio, F; Schrock, A B; Lee, J; Morano, F; Fucà, G; Nikolinakos, P; Drilon, A; Hechtman, J F; Christiansen, J; Gowen, K; Frampton, G M; Gasparini, P; Rossini, D; Gigliotti, C; Kim, S T; Prisciandaro, M; Hodgson, J; Zaniboni, A; Chiu, V K; Milione, M; Patel, R; Miller, V; Bardelli, A; Novara, L; Wang, L; Pupa, S M; Sozzi, G; Ross, J; Di Bartolomeo, M; Bertotti, A; Ali, S; Trusolino, L; Falcone, A; de Braud, F; Cremolini, C;
• Is Part Of: Annals of oncology. Volume 29:Number 6(2018)
• Page Start: 1394
• Page End: 1401
• Publication Date: 2018-03-10
• Subjects: RET -- colorectal cancer -- gene fusions -- targeted therapy -- MSI-high -- prognosis; Oncology -- Periodicals; 616.992
• DOI: 10.1093/annonc/mdy090
• Languages: English
• ISSNs: 0923-7534

Abstract

Abstract: Background: Recognition of rare molecular subgroups is a challenge for precision oncology and may lead to tissue-agnostic approval of targeted agents. Here we aimed to comprehensively characterize the clinical, pathological and molecular landscape of RET rearranged metastatic colorectal cancer (mCRC). Patients and methods: In this case series, we compared clinical, pathological and molecular characteristics of 24 RET rearranged mCRC patients with those of a control group of 291 patients with RET negative tumors. RET rearranged and RET negative mCRCs were retrieved by systematic literature review and by taking advantage of three screening sources: (i) Ignyta's phase 1/1b study on RXDX-105 ( NCT01877811 ), (ii) cohorts screened at two Italian and one South Korean Institutions and (iii) Foundation Medicine Inc. database. Next-generation sequencing data were analyzed for RET rearranged cases. Results: RET fusions were more frequent in older patients (median age of 66 versus 60 years, P = 0.052), with ECOG PS 1–2 (90% versus 50%, P = 0.02), right-sided (55% versus 32%, P = 0.013), previously unresected primary tumors (58% versus 21%, P < 0.001), RAS and BRAF wild-type (100% versus 40%, P < 0.001) and MSI-high (48% versus 7%, P < 0.001). Notably, 11 (26%) out of 43 patients with right-sided, RAS and BRAF wild-type tumors harbored a RET rearrangement. At a median follow-up of 45.8 months, patients with RET fusion-positive tumors showed a significantly worse OS when compared with RET -negative ones (median OS 14.0 versus 38.0 months, HR: 4.59; 95% CI, 3.64–32.66; P < 0.001). In the multivariable model, RET rearrangements were still associated with shorter OS (HR: 2.97; 95% CI, 1.25–7.07; P = 0.014), while primary tumor location, RAS and BRAF mutations and MSI status were not. Conclusions: Though very rare, RET rearrangements define a new subtype of mCRC that shows poor prognosis with conventional treatments and is therefore worth of a specific management.