The international collaboration of active surveillance trials for low-risk DCIS (LORIS, LORD, COMET, LORETTA).

Abstract

TPS603 Background: Retrospective data suggest breast cancer-specific survival rates with versus without surgery in patients with low-grade ductal carcinoma in situ (DCIS) are similar. Some DCIS patients have a low likelihood of progression to invasive cancer, but predicting who is at risk has not been established. Thus, treatment with a well-balanced risk / benefit ratio has not been achieved. Four active surveillance clinical trials for low risk DCIS have commenced in the United Kingdom (LORIS), Europe (LORD), United States (COMET), and Japan (LORETTA). We aim to examine the effectiveness & safety of active surveillance compared with surgical based treatment approaches for low-risk DCIS patients. Methods: Non surgical approaches are of the two types; active surveillance (AS) alone and AS + endocrine therapy (ET). In the randomized trials LORIS and LORD, the study arms are AS only, but while ET is an option in COMET, ET is mandatory in the single arm trial LORETTA. COMET and LORETTA have broader inclusion criteria as compared to LORIS and LORD. In COMET, comedo necrosis is eligible. In LORETTA, findings other than calcification on mammography (MMG) are also eligible (e.g. low echo area on breast ultrasound). Leaders of the four trials hold regular meetings to foster international DCIS trials collaboration to share information. LORIS Clinical trial information: ISRCTN27544579, LORD Clinical trial information: NCT02492607, COMET Clinical trial information: NCT02926911, LORETTA Clinical trial information: UMIN000028298 [JCOG1505]. Clinical trial information: UMIN000028298, NCT02492607, NCT02926911, ISRCTN27544579. [Table: see text]