HER2+ / HR+ early breast cancer

Breast cancer epidemiology

Breast cancer is the most common cancer in women, with more than 2 million new cases each year worldwide.

Amplification or overexpression of HER2 occurs in approximately 15–30% of breast cancers.¹⁵
Around 80% of breast cancers test positive for ER, with 65% of these also testing positive for PR.²⁹
Around 10% of breast cancers are HER2+/HR+.³⁰

Breast cancer in females by subtype (%)³⁰ :

Image

Risk considerations in HER2+/HR+ early breast cancer

Without further treatment, 20-30% of patients with HER2+/HR+ disease will experience disease recurrence within 10 years of completing trastuzumab-based therapy. ^{1-3,6,7,31-36}

HER2, human epidermal growth factor receptor 2; HR+, hormone receptor positive.
a Recurrence refers to DFS, defined as the time from enrolment to documentation of the first of any of these events: local, regional or distant recurrence of breast cancer; a contralateral breast cancer; a second primary cancer; or death as a result of any cause.³²
b Recurrence refers to DFS, defined as the time from randomisation to the first occurrence of any of these events: recurrence of breast cancer at any site; the development of ipsilateral or contralateral breast cancer, including ductal carcinoma in situ but not lobular carcinoma in situ; second non-breast malignant disease other than basal-cell or squamous-cell carcinoma of the skin or carcinoma in situ of the cervix; or death from any cause.³⁶
c Recurrence refers to iDFS, defined as time from randomisation to the first occurrence of any of the following events: recurrence of ipsilateral invasive breast tumour, recurrence of ipsilateral locoregional invasive breast cancer, contralateral invasive breast cancer, a distant disease recurrence or death from any cause.^7,34
d Recurrence defined as the first occurrence of any of the following events: recurrence of ipsilateral invasive breast tumour, recurrence of ipsilateral locoregional invasive breast cancer, contralateral invasive breast cancer, a distant disease recurrence, or death from any cause.