Breast Cancer Awareness Month: Awareness, Early Detection, and New Opportunities Through Immunotherapy

Every October, people and foundations wear a pink ribbon to show their support for Breast Cancer Awareness Month. The symbol is intended to raise awareness about breast cancer, provide information on early detection, and support those affected. In 2022, approximately 2.3 million new cases of breast cancer and about 670,000 deaths were recorded worldwide. This makes breast cancer the most common form of cancer among women.

At the same time, diagnostic methods and treatments have advanced significantly. Breast cancer is not a uniform disease: Tumors differ, among other things, in whether they express hormone receptors or the HER2 protein. These biological characteristics play a key role in determining which treatment is appropriate.

Early Detection and Personalized Treatment

The earlier breast cancer is detected, the better the treatment options are in most cases. Any noticeable changes—such as a new lump, an inverted nipple, changes in the skin, or unusual discharge—should therefore be evaluated by a doctor.

After a diagnosis is made, the tumor tissue is examined in greater detail. In addition to surgery, radiation therapy, and chemotherapy, treatment options include, depending on the tumor type, anti-hormone therapies, HER2-targeted drugs, antibody-drug conjugates, and, for selected patients, immunotherapies.

Established Immunotherapy: Checkpoint Inhibitors

The immunotherapy for breast cancer with the strongest scientific evidence is currently provided by so-called immune checkpoint inhibitors. They release certain “brakes” on the immune system, allowing immune cells to attack tumor cells more effectively.

This is particularly relevant in the case of triple-negative breast cancer (TNBC). This type of tumor has neither hormone receptors nor HER2 overexpression.

The active ingredient pembrolizumab is approved in the EU for patients with early-stage or locally advanced TNBC and a high risk of recurrence. It is administered before surgery in combination with chemotherapy and then continued as monotherapy for a limited period. A positive PD-L1 test is not required for this use. For inoperable locally recurrent or metastatic TNBC, pembrolizumab is also approved in combination with chemotherapy if the tumor expresses sufficient PD-L1—specifically, with a Combined Positive Score of at least 10.

However, checkpoint inhibitors can cause immune-related side effects, such as inflammation of the thyroid, lungs, intestines, liver, or other organs. Therefore, the benefits and risks must be weighed on a case-by-case basis.

Dendritic Cell Therapy

In addition to established checkpoint inhibitors, other immunological therapies are being developed. These include dendritic cell therapy.

Dendritic cells are among the most important antigen-presenting cells of the immune system. Simply put, they present characteristic components of a tumor to T cells and can thereby trigger a targeted immune response. In novel cancer vaccines, for example, dendritic cells are exposed to tumor antigens and then used to activate the immune system.

Clinical trials involving such vaccines are also underway for breast cancer, including TNBC. Review articles describe a number of ongoing or completed early-phase clinical trials.

The key limitation: Dendritic cell therapy is not currently an established standard treatment for breast cancer. This would require randomized Phase III trials, which are considered the most reliable form of evidence. In this sense, its use is permitted only within the framework of a clinical trial or an individual experimental treatment.

Oncolytic Virotherapy

Viral therapy is also an interesting area of research. This approach uses what are known as oncolytic viruses, which are designed to selectively infect and destroy tumor cells. At the same time, this process can release tumor components that activate the immune system.

An important research goal is to transform a tumor that is immunologically “cold” into a “hot” tumor that is more easily recognized by immune cells. For this reason, oncolytic viruses are often studied in combination with checkpoint inhibitors. The biological rationale is well-established and has also been tested in clinical trials for various types of cancer.

For breast cancer, oncolytic virotherapy is not currently part of the standard of care.

What does “ICD therapy” mean?

The term ICD stands for immunogenic cell death. Strictly speaking, it is not a single, well-defined therapy, but rather a biological mechanism.

Certain types of tumor cell death release signals and tumor antigens that can activate immune cells. As a result, the destruction of the cancer cell simultaneously serves as a kind of warning signal to the immune system. Various treatments can trigger such processes—including certain types of chemotherapy, radiation therapy, experimental drugs, and local procedures.

Targeted enhancement of immunogenic cell death is the subject of intensive research, including in the context of breast cancer. The hope is that this will make tumors more responsive to subsequent immunotherapies. Scientific reviews see great potential in this approach but also emphasize that many targeted ICD strategies are still in the early stages of clinical development.

Research with great potential—but varying levels of evidence

Not all immunotherapies are the same. Pembrolizumab for selected patients with TNBC is a scientifically well-established and approved treatment. Dendritic cell vaccines and oncolytic viruses are currently being studied in clinical trials but have not yet been established as treatments for breast cancer. Immunogenic cell death, on the other hand, is a key mechanism that new therapies are designed to target.

It is precisely this distinction that is important: Progress in cancer medicine comes not only from new ideas, but also from the ability to put them into practice.

Sources – Selection:

International Agency for Research on Cancer (IARC) / WHO, Global Cancer Observatory – GLOBOCAN 2022: Breast Cancer Fact Sheet; European Medicines Agency (EMA),
Keytruda – Pembrolizumab, European Public Assessment Report. Schmid P, Cortes J, Dent R, et al.; KEYNOTE-522 Investigators, “Event-free Survival with Pembrolizumab in Early Triple-Negative Breast Cancer,” New England Journal of Medicine. 2022;386(6):556–567; Galluzzi L, Guilbaud E, Schmidt D, Kroemer G, Marincola FM, Targeting immunogenic cell stress and death for cancer therapy, *Nature Reviews Drug Discovery*. 2024;23(6):445–460; Bahreyni A, Mohamud Y, Luo H. Oncolytic virus-based combination therapy in breast cancer. Cancer Letters, March 31, 2024; National Cancer Institute (NCI), HER2 and HER3-Directed Dendritic Cell Vaccine for the Treatment of Early-Stage Triple-Negative or Hormone Receptor-Low Breast Cancer – DecipHER Trial. ClinicalTrials.gov: NCT05504707.

As of October 2026. This article is intended for general informational purposes only and is not a substitute for individual medical advice.