Definition
A.Uncontrolled growth of breast cells, usually forming a tumor that can be felt as a lump or seen on a x-ray.
B.Malignant tumors invade the surrounding tissues or metastasize to distant body areas.
C.Breast cancer can be curable, and early detection yields a favorable prognosis.
Incidence
A.Breast cancer is the most commonly diagnosed cancer in American women, and approximately 12.4% of women in the United States will develop invasive breast cancer during their lifetime.
B.After increasing for more than 20 years, breast cancer incidence rates in women have stabilized since 2000, possibly related to fewer women using hormone replacement therapy after menopause.
C.Breast cancer is the second leading cause of cancer deaths in women, second only to lung cancer.
D.The chance that a woman will die from breast cancer is about 1 in 36 (∼3%).
E.The median age of diagnosis of breast cancer for women in the United States is 68.
F.Fewer than 5% of women diagnosed with breast cancer in the United States are younger than 40.
G.Risk of breast cancer increases with age, and is highest for women over the age of 70.
H.Breast cancer is much less common in men than in women, with men in the United States experiencing a 1 in 1,000 lifetime risk of developing breast cancer.
Pathogenesis
A.Ductal carcinoma in situ (DCIS).
1.DCIS is considered noninvasive or preinvasive breast cancer.
2.The cells that line the ducts of the breast have become dysplastic but remain contained within the walls of the ducts and have not spread into the surrounding breast tissue.
3.DCIS accounts for approximately 20% of new diagnoses of breast cancer.
B.Lobular carcinoma in situ (LCIS).
1.LCIS is a collection of abnormal cellular growth inside one or more of the milk-producing glands in the breast (called lobules).
2.As the abnormal cells have not grown outside of the lobules, it is considered in situ.
3.Although it is not considered cancer, it is associated with a higher risk of developing invasive cancer in the future.
4.LCIS is not very common and usually occurs in premenopausal women.
5.LCIS is considered higher risk as it typically does not cause symptoms and can be difficult to see on imaging, making it difficult to detect.
6.It is usually found incidentally when the breast is biopsied for some other reason.
C.Invasive ductal carcinoma (IDC).
1.This is the most common type of breast cancer and accounts for approximately 80% to 85% of all new breast cancer diagnoses.
2.IDC (or infiltrating) starts within the duct and grows into the adipose tissue of the breast.
3.Breaking beyond the ductal wall means it now has the capability to spread to other areas of the body through lymphatic spread.
D.Invasive lobular carcinoma (ILC).
1.ILC starts in the milk-producing glands (lobules) and has invaded into the adipose tissue of the breast and therefore can metastasize to other parts of the body.
2.Accounts for about 10% of breast cancers.
3.It is considered higher risk as it can be difficult to see on imaging, making detection and monitoring for recurrence difficult.
E.Inflammatory breast cancer (IBC).
1.IBC is a rare but aggressive form of invasive breast cancer, and accounts for about 1% to 3% of all breast cancers.
2.There may not be a palpable mass or tumor, so it may not be seen on imaging. Sometimes skin thickening can be seen on mammogram.
3.Often mistaken as cellulitis of the breast, as it presents with redness, warmth, and edema to the skin of the breast, often causing an orange peel appearance.
a.This is caused not by infection but by cancer cells blocking lymph vessels in the skin, causing congestion.
b.If cellulitis is suspected and the patient fails to respond after a course of antibiotics, timely or prompt mammogram and biopsy should be considered.
4.Time is of the essence with IBC given the strong potential for rapid progression.
5.IBC is considered a more aggressive breast cancer and is associated with poorer prognosis when compared to IDC.
F.Other less common breast cancers and tumors: Angiosarcoma, medullary, mucinous, Paget’s disease, papillary, phyllodes, tubular.
Predisposing Factors
A.Nonmodifiable.
1.Family history.
2.Genetic mutation or diagnosis (including BRCA1/2 gene mutations, Cowden syndrome, and Li–Fraumeni syndrome).
3.Race (white women are more likely to develop breast cancer than other ethnicities).
4.Gender (women > men).
5.Personal history of breast cancer.
6.Breast cellular changes (such as hyperplasia).
B.Modifiable.
1.Smoking.
2.Obesity (fat cells produce estrogen).
3.Increased alcohol consumption (alcohol can limit your liver’s ability to control blood levels of the hormone estrogen).
4.Sedentary lifestyle.
5.Exposure to estrogen (nulliparity, early onset of menorrhea, delayed onset of menopause, hormone replacement therapy, never breastfeeding).
6.Use of oral contraceptives (there is an immediate increased risk, but that risk resolves over time after discontinuation).
7.Prior radiation to the breast or chest wall.
Subjective Data
A.Common complaints/symptoms.
1.Localized disease.
a.Pain, swelling, or redness in the breast.
b.Nipple changes, inversion, or discharge.
c.Skin changes, thickening, dimpling, or scaling in the breast or nipple.
d.With lymphatic spread, patients may experience painful or enlarged lymph nodes in the axilla, chest, or neck.
2.Metastatic disease.
a.Weight loss and/or change in appetite.
b.Persistent, nagging, or worsening pain (visceral or bone/joint).
c.Shortness of breath or cough.
d.Headache.
e.Fatigue.
B.Common/typical scenario.
1.Due to increased awareness and screening, breast cancer can frequently be found on screening mammograms, by self-breast examination, or by providers performing breast surveillance examinations.
2.When patients present with symptoms outside of the breast, they likely have already developed metastatic disease.
Physical Examination
A.In addition to evaluating for disease in the primary site (breast), evaluate for possible metastatic disease.
B.The most common sites of breast cancer metastases are brain, bone, liver, and lung.
C.Check vital signs including pulse oximetry.
D.A thorough baseline cardiac examination is important, as some chemotherapies used to treat breast cancer are associated with risk for cardiotoxicity. Many chemotherapies used to treat breast cancer can cause neuropathies, so it is important to assess for any preexisting neuropathies at baseline that may not be related to cancer (such as diabetic neuropathy or prior nerve damage due to injury).
E.Breast examination.
1.Should be performed in the sitting position with arms at side and raised above head, and again while lying supine with the same arm positions. If a patient has a self-palpated mass, ask the patient in which position he or she was best able to feel the mass. Do not forget to also examine the nipple–areolar complex.
2.Once the mass is located, measure with a disposable measuring tape by isolating the mass between the thumb and forefinger and noting the distance between your digits. Note which quadrant of the breast the mass is in.
3.Assess the skin of the breast, including skin overlying the mass and the nipple for changes such as redness, peau d’orange appearance, edema, scaliness, or even an open lesion.
4.If the patient notes nipple discharge, the breast can be gently pressed to try and elicit the discharge so the output can be evaluated. If unable to easily express discharge, do not utilize increasing pressure. Sometimes the patient will have discharge that has collected in a bandage or her bra that can be evaluated. Note the color, amount, and consistency.
5.Lymph nodes should also be evaluated in the sitting and supine positions. Include bilateral evaluation of axilla, supraclavicular, infraclavicular, cervical, and mandibular regions. If lymph nodes are palpated, note size, consistency, if fixed or mobile, and if patient reports tenderness with palpation.
F.Evaluate for metastatic disease.
1.Pulmonary: Observe for signs of dyspnea, increased work of breathing, or retractions; evaluate for pleural effusions (auscultation, percussion, and cacophony).
2.Musculoskeletal: Bone tenderness, impaired range of motion.
3.Abdomen: Assess for hepatomegaly, ascites, mass, or tenderness.
4.Neurological: Incoordination, focal deficits, visual changes, hearing changes, decreased strength.
Diagnostic Tests
A.History and physical examination.
B.Diagnostic bilateral mammogram with tomosynthesis, which provides higher resolution when evaluating someone who has a known mass or breast abnormality; ultrasound of the breast as necessary (or as recommended by the radiologist).
C.Breast biopsy and clip placement. Ultrasound of nodal basin on the ipsilateral side.
D.Pathology review; determination of hormone receptor status (estrogen/progesterone receptor and human epidermal growth factor receptor 2 [HER2]).
E.Breast MRI when indicated. This is usually recommended by the radiologist if dense breast tissue obscures the mass, there is a question of the size of the mass, or concern is observed for involvement of the chest wall.
F.Breast cancer is predictable. It starts in the breast, moves to the regional lymph nodes, and then metastasizes to distant sites in the body. If nodal ultrasound is negative and there are no findings on physical examination to suggest metastasis, systemic staging is not indicated (per National Comprehensive Cancer Network [NCCN] guidelines). If a suspicious node is noted on imaging or examination, proceed with biopsy of lymph node. If positive, proceed with metastatic workup.
1.Complete blood count (CBC), comprehensive metabolic panel (CMP).
2.CT chest, abdomen, pelvis with contrast.
3.Bone scan.
4.PET scan, if indicated.
G.Diagnosis.
1.Tissue sample or biopsy is required for diagnosis. Pathology results will help guide the next step of workup, referral/provider evaluation, and recommended interventions.
2.It is imperative to send biopsy sample(s) for estrogen/progesterone (ER/PR) and HER-2/neu testing, as these results are required for prognostication and therapy recommendations.
H.Staging: Breast cancer is staged utilizing the American Joint Committee on Cancer (AJCC) tumor, node, metastasis (TNM) system.
Differential Diagnosis
A.DCIS.
B.LCIS.