Invasive vs Non Invasive Breast Cancer
Lump in the breast is a common presentation in the current surgical practice. It could be a benign condition such as a simple fibro adenoma or else could be malignant. Anyway, to be on the safe side any lump in the breast must be considered as malignant until otherwise proven. Diagnosis of breast cancer is based upon triple assessment, which includes clinical findings, imaging findings, and cytological confirmation. Carcinomas can further be classified depending on the histological classification according to its site of origin and invasiveness.
Invasive Breast Carcinoma
Invasive breast carcinoma could be either ductal or lobular carcinoma. The most common type of breast cancer that accounts for 75% of all cases is the invasive ductal carcinoma. Usually the patient can present with feeling of a hard lump in the breast. Macroscopically it forms a gritty and rocky-hard infiltrative mass in which yellowish white chalk streaks are characteristic. Extensive fibrosis can be seen. Microscopically it appears as highly pleomorphic ductal epithelial cells infiltrating the fibrous stroma of the breast tissue. Lymphatic invasion is a common feature.
5-10% of all breast carcinomas are invasive lobular type. They are similar to invasive ductal carcinoma except for a different histological pattern of infiltration and a greater risk of estrogen receptor positivity.
Management of invasive carcinoma should be aggressive which include total mastectomy with axillary clearance followed by radiotherapy and chemotherapy.
Non Invasive Breast Carcinoma (in situ carcinoma)
Again non invasive breast carcinoma could be either lobular carcinoma in situ or ductal carcinoma in situ, and both of them have no risk of dissemination as long as the tumour remains in situ.
Lobular carcinoma in situ is a neoplastic proliferation of the lobular epithelial cells that fill and distend all the acini with malignant cells, but the basement membrane is intact. It tends to be multifocal and bilateral. Clinically the patient may not have any palpable mass and may have a completely normal mammogram. This increases the risk of development of breast carcinoma by 10 fold and both breasts are at risk. Management is highly controversial which ranges from careful follow up to bilateral total mastectomy.
Ductal carcinoma in situ is a neoplastic proliferation of the ductal epithelial cells confined within the basement membrane. It may be associated with infiltrating ductal carcinoma. Clinically it produces a hard mass. Calcification is a common feature, which makes it detectable by mammography. Microscopically involved ducts are distended with malignant cells that are arranged in cribriform, papillary or solid patterns. The cells are large and uniform with well defined cell membranes.
Management varies with the size of the lesion. If <2cm, lumpectomy with wide local excision is done. For lesions > 2cm, mastectomy is usually recommended.
What is the difference between Invasive and Non Invasive Breast Carcinoma?
• Invasive breast carcinoma is more common than non invasive type.
• Usually, patients with invasive carcinoma present with a clinically palpable mass, but non-invasive type patient may or may not have any clinical symptoms.
• In invasive variety, the tumor has breached the basement epithelium and has spread to involve the rest of breast tissue, but in non-invasive type, the basement membrane is intact.
• Non invasive type tends to be more bilateral.
• Management is different in these two conditions.