Inflammatory breast cancer: An atypical breast cancer type

Inflammatory breast cancer (IBC) is a less common form of breast cancer first described by Lee and Tannenbaum in 1924. In spite of medical advances it remains a clinical diagnosis based on visible symptoms rather than a specific molecular or pathological test.

Robust statistics are challenging in a less common disease such as IBC. Most studies are from single institutions, complicating the ability to accurately compute incidence, median age, and racial/ethnic demographics. However, the majority of studies suggest younger age at diagnosis (median age, 53 years at presentation) and a higher incidence of IBC among African Americans.¹ A 2014 study using Surveillance, Epidemiology, and End Results (SEER) data speaks to the higher incidence as well as a higher mortality in African Americans, particularly those with estrogen/progesterone negative tumors.²

Another large population-based study looked at survival in a cohort of 7,679 patients with a diagnosis of IBC between 1990 and 2010.³ The patients were divided into four subgroups according to year of diagnosis. The results show an improvement in 2-year breast cancer specific survival (BCSS) from 62% (1990-1995) to 76% (2006-2010), supporting the benefit of new systemic therapies available in the last 4 years of the study period. The 2-year BCSS for the whole cohort was 71%.³

The most obvious risk factor is female sex; although IBC has been diagnosed in males, they tend to be older at diagnosis. Cited risk factors for IBC include younger age at menarche and at time of first live birth, compared with non-inflammatory breast cancer; high body mass index (BMI); premenopausal state; and socioeconomic status.⁴ These same risk factors have been identified in other breast cancers and, for the most part, are not unique to IBC. The higher incidence in young premenopausal women contributes to both diagnostic challenges and discovering the risk factors associated with disease development.

Patients typically present with a series of clinical signs and symptoms. They may include a rapid increase in breast size, redness, warmth, peau d’orange (skin that resembles an orange peel), itching, and pain. The erythema and edema usually affect one-third or more of the breast. Patients may have what appears to be a bruise or bug-bite associated with a rash that has not healed. Other breast changes such as nipple inversion or heaviness of the breast may be present. The hallmark of IBC is the rapid progression of symptoms, often occurring in less than 3 months, in contrast to locally advanced or neglected breast cancer that may exhibit similar symptoms but develop over a longer period of time; occasionally 6 months to 1 year.⁵

Due to the younger age at diagnosis patients may be reluctant to seek evaluation for symptoms or be dismissed by the medical community as too young to develop breast cancer. In addition, symptoms are frequently mistaken for mastitis. Antibiotics are often given repeatedly resulting in inappropriate treatment and a delayed diagnosis. Although the breast may look infected, the symptoms are actually caused by cancer cells blocking the lymphatic vessels of the skin causing lymph fluid to back up within the skin of the breast.

The diagnostic process can be challenging. IBC is a clinical rather than pathological diagnosis relying on the experience of the health care provider to recognize the disease. A palpable mass may or may not be present. Mammography is often of little value in IBC but may show skin thickening. The presence of increased breast density, normally seen among young women, may also confound the diagnosis of IBC. Other imaging modalities such as ultrasound and magnetic resonance imaging (MRI) appear to be of value in the diagnostic process. Skin punch biopsies are taken from areas with the most visible skin changes and used to check for dermal lymphatic invasion by tumor cells. However, in most cases an additional biopsy of the breast will be needed to confirm a diagnosis of invasive carcinoma.

The National Comprehensive Cancer Network (NCCN) has updated their Breast Cancer Screening and Diagnosis Guideline to provide a comprehensive diagnostic pathway to rule out IBC. BSCR-14 guides the health care practitioner through the diagnostic process step by step.⁸