Invasive lobular carcinoma (ILC) is a distinct form of breast cancer, differing from invasive ductal carcinoma. Approximately 10% to 15% of all breast cancer diagnoses are ILC, making it the second most frequent type. Many individuals diagnosed with ILC experience long-term survival, attributed to advancements in understanding and treating this cancer. This article explores what long-term survivors of ILC can anticipate regarding their health and well-being.
Understanding Invasive Lobular Carcinoma
Invasive lobular carcinoma originates in the breast’s milk-producing glands (lobules). Its unique characteristic is how its cells grow: instead of forming a distinct lump, ILC cells infiltrate breast tissue in single-file lines. This diffuse growth pattern makes ILC challenging to detect through standard imaging, such as mammography, which is more effective at identifying solid masses.
The subtle growth of ILC cells can lead to larger tumors by diagnosis, even though ILC is often slow-growing. Due to its diffuse nature, ILC can also be multifocal (multiple tumors in one area), multicentric (multiple tumors in different areas of the same breast), and bilateral (affecting both breasts). This unique cellular behavior is attributed to the loss of E-cadherin, a protein responsible for cell-to-cell adhesion.
Prognosis and Recurrence Patterns
A “long-term survivor” in breast cancer refers to individuals who have lived many years after initial diagnosis and treatment. While the initial prognosis for ILC can be favorable, it has a tendency for late recurrences, sometimes occurring more than five years after diagnosis. Factors like younger age at diagnosis and a higher body mass index (BMI) may be associated with late recurrence.
ILC exhibits distinct patterns of metastasis compared to other breast cancer types. While it can spread to common sites like bones, ILC shows a higher propensity to metastasize to unusual locations such as the gastrointestinal (GI) tract, peritoneum (lining of the abdomen), retroperitoneum (space behind the abdominal lining), and ovaries. It may also spread to the pleura (lining of the lung) and, in rarer instances, the leptomeninges (lining of the brain and spinal cord). Conversely, ILC is less likely to metastasize to the lungs or liver compared to invasive ductal carcinoma.
Ongoing Surveillance and Management
Given ILC’s unique recurrence patterns, tailored long-term surveillance strategies are important. Regular clinical exams are a cornerstone of follow-up care. However, traditional mammography has lower sensitivity for detecting ILC due to its diffuse growth, with reported sensitivities ranging from 57% to 81%.
Supplemental imaging, such as breast magnetic resonance imaging (MRI), is recommended, especially for younger women, as it has higher sensitivity for ILC detection, often exceeding 95%. MRI can more accurately assess tumor size, extent of disease, and identify multifocal or bilateral involvement. Digital breast tomosynthesis (DBT) also shows improved sensitivity for ILC compared to standard digital mammography.
Endocrine therapy, which targets hormone receptors, is a common and often long-term treatment for ILC, as most ILC tumors are hormone-receptor-positive. This therapy can last for several years and may lead to side effects such as joint pain and fatigue. It is important for ILC survivors to report any new or unusual symptoms to their healthcare team, especially those indicating spread to less common metastatic sites like persistent abdominal pain, changes in bowel habits, or unexplained swelling.
Living Well After ILC Treatment
Life after ILC treatment involves managing physical and emotional well-being. Fatigue is a common long-term side effect of cancer treatment, often persisting for months or even years. Maintaining a healthy lifestyle, including balanced nutrition and regular physical activity, can help manage lingering effects.
Emotional well-being is a significant aspect of survivorship. Many survivors experience anxiety, depression, and a fear of recurrence, which can be particularly intense in the first year after treatment. Connecting with support groups, other survivors, or seeking professional mental health support can provide comfort and coping strategies. Being informed about ILC and openly discussing feelings of fear, anger, or sadness can help individuals feel more in control and better able to navigate their post-treatment journey.