Breast cancer can sometimes spread beyond its original site. When cancer cells from the primary breast tumor establish new growths in the skin, these are known as breast cancer skin metastases. Patients often experience various symptoms with these skin changes, and a frequent concern is whether these lesions can cause itching. This article explores breast cancer skin metastases and the reasons behind any associated itching.
What Are Breast Cancer Skin Metastases?
Breast cancer skin metastases occur when cancer cells from the breast tumor spread to the skin. This typically happens through the bloodstream or the lymphatic system, which are networks of vessels that transport fluids and immune cells throughout the body. Circulating cancer cells can then grow in the skin, forming new tumors.
The appearance of skin metastases can vary considerably. They commonly present as firm, painless nodules under the skin, often near the original tumor site, such as the chest wall. Nodules can range in size from tiny, like a pea, to larger formations. The overlying skin might initially appear normal, but over time, it can show subtle changes in color or texture, sometimes becoming reddish, purplish, or darker.
Skin metastases can also manifest as papules, plaques, or inflammatory patches. Some may resemble skin infections like cellulitis, characterized by persistent redness and inflammation that does not respond to typical treatments. Less common forms include lesions mimicking vascular malformations or diffuse hardening of the skin. In some cases, skin metastases can be the first visible sign of cancer spread, even years after initial breast cancer diagnosis and treatment.
Why Skin Metastases Can Cause Itching
Breast cancer skin metastases can cause itching, a symptom medically termed pruritus. This itching arises from several mechanisms related to the presence and activity of tumor cells in the skin. The direct infiltration of tumor cells into the skin can trigger an inflammatory response.
This inflammation involves the release of chemical mediators, such as histamines and cytokines, by tumor cells and the body’s immune cells. These substances can irritate nerve endings in the skin, leading to the sensation of itching. The itch from pruritus may feel similar to pain because both sensations share common nerve pathways.
Furthermore, metastatic lesions can directly irritate or compress nearby nerves in the skin. This nerve involvement can lead to neuropathic itching, a type of itch that originates from damage or dysfunction of the nervous system. Sometimes, the skin overlying the metastases may also become dry, which can independently contribute to or worsen itching. Certain cancer treatments, including some targeted therapies, can also cause dry, itchy skin as a side effect.
Relieving Itching and Other Skin Symptoms
Managing itching and other skin symptoms associated with breast cancer skin metastases involves medical interventions and supportive care strategies. Systemic cancer therapies, such as chemotherapy, hormone therapy, targeted therapy, or immunotherapy, are often the primary approach, as reducing the overall tumor burden can alleviate symptoms. For localized relief, radiation therapy is commonly used, particularly for painful or ulcerated skin lesions.
Topical treatments can also provide symptomatic relief. Corticosteroid creams help reduce inflammation and itching. Antihistamines may help block the effects of histamine, a chemical that contributes to itching. For severe neuropathic itching, medications like gabapentin may be prescribed. In some cases, topical chemotherapy agents like 5-fluorouracil or other experimental creams are being investigated.
Supportive care measures also play a role in managing skin symptoms. Regular moisturizing with unscented and uncolored emollients can combat dry skin and soothe irritation. Applying cool compresses to itchy areas can provide temporary relief. Gentle skin hygiene, avoiding harsh soaps, very hot water, and vigorous rubbing when drying, can prevent further irritation. Wearing loose-fitting clothing made from natural fibers like cotton can also minimize skin friction.