Breast Cancer in Situ

Question 1

Define breast cancer in situ.

Answer 1

Breast cancer in situ is cancer that is confined to the duct or lobule in which it originated and does not extend beyond the basement membrane.

Question 2

Explain the aetiology/risk factors of breast cancer in situ.

Answer 2

Family history of breast cancer
Benign breast disease on prior biopsy
Hereditary breast ovarian cancer syndrome
Li-Fraumeni syndrome: Mutation of P53 gene
Cowden’s syndrome: Mutation of PTEN
Klinefelter’s syndrome: 47, XXY

Question 3

Summarise the epidemiology of breast cancer in situ.

Answer 3

In the US, it has been estimated that in 2018 there will be 63,960 new cases of breast carcinoma in situ. DCIS comprises 85% and LCIS 15% of in situ carcinomas of the breast.

Question 4

Recognise the presenting symptoms of breast cancer in situ. Recognise the signs of breast cancer in situ on physical examination.

Answer 4

Nipple discharge
Breast lump
Eczema-like rash on breast
Ulceration

Question 5

Identify appropriate investigations for breast cancer in situ and interpret the results.

Answer 5

Mammogram
FNA