Lobular breast cancer and prognosis: what should we tell patients?

BACKGROUND: Invasive lobular carcinoma (ILC) is the second most common subtype of breast cancer. It accounts for up to 15% of all breast cancer diagnoses, and there is an increasing population of people living with a diagnosis of 'lobular'. ILC has historically been understudied and is underrepresented in clinical trials. Presenting with pathology features typical of a good prognosis (oestrogen receptor-positive, HER2-negative, grade 2), a diagnosis of ILC can be framed as one with a 'good outcome'. But whether the data support this over time remains to be seen. METHODS: We present a comprehensive narrative review to ascertain whether ILC has a better outcome than invasive carcinoma of no special type (IC-NST). RESULTS: A number of the research studies analysed showed that ILC can have a better outcome at 5 years and still have a poorer outcome over time, whilst others showed that IC-NST has a poor outcome early, which is maintained over time. CONCLUSIONS: We discuss limitations and confounders and, critically, give voice to the people living with a lobular breast cancer diagnosis.