COULD A CANCER-KILLING VIRUS help chemotherapy to eliminate an aggressive form of breast cancer? A new study offers some hope, showing that a cancer-killing virus that can preferentially infect cancer cells when injected into a tumor might have an anti-tumor effect.
I wanted to share news about this novel approach to cancer management. However, let me begin by sharing that I think the outcomes are not extraordinary (back to that later).
First, a quote that I enjoy (but that has virtually nothing to do with our topic):
“And those who were seen dancing were thought to be insane by those who could not hear the music.”
― Friedrich Nietzsche
What is triple-negative breast cancer?
As the new research findings apply to a breast cancer subtype, I want to explore triple-negative breast cancer quickly.
Triple-negative breast cancer (TNBC) is a breast cancer type that lacks the expression of three receptors commonly found in breast cancer cells: the estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2). These receptors are targeted by hormonal therapies or medications that block the HER2 protein, respectively.
Because triple-negative breast cancer cells lack these receptors, they are not responsive to hormone therapy or HER2-targeted medications. This fact makes TNBC more difficult to treat than other types of breast cancer, as chemotherapy is the primary treatment option.
Triple-negative breast cancer accounts for approximately 10 to 20 percent of all breast cancer cases. It is more likely to affect younger women, African American women, and women with BRCA1 mutations. Treatment options may include chemotherapy, surgery, and radiation therapy. Clinical trials are also exploring new treatments and therapies for TNBC.
What is neoadjuvant therapy?
Neoadjuvant chemotherapy is often recommended for TNBC because it can shrink the tumor and potentially increase the chance of breast-conserving surgery rather than breast removal.
While all systemic therapies (including chemotherapy) for localized invasive breast cancer are designed to reduce cancer spread to distant sites, giving treatment before surgery provides information about the treatment response.
The presence and extent (or absence) of residual invasive cancer after preoperative (neoadjuvant) therapy is a strong prognostic factor for recurrence risk, especially for more aggressive breast cancer subtypes. Individuals with a complete response (no residual cancer) to neoadjuvant drugs tend to have a better prognosis than those with residual disease.
After surgery, additional treatment may be recommended depending on the patient’s risk factors.
A cancer-killing virus for breast cancer
While triple-negative breast cancer remains challenging, a new cancer-killing virus (with the unwieldy name talimogene laherparepvec (TVEC) offers new hope. Researchers recently published the results of a phase 2 trial in Nature Medicine.
In an early clinical trial, 46 percent of patients receiving TVEC injections directly into the tumor (during chemotherapy before surgery) had no signs of cancer at the time of surgery.
The preferred treatment approach for localized triple-negative breast cancer is neoadjuvant (before surgery) chemotherapy. Selected patients may also receive immunotherapy. Neoadjuvant chemotherapy is often recommended for TNBC because it can shrink the tumor and potentially increase the chance of breast-conserving surgery rather than a full mastectomy.
Does this study recommend a great scientific leap? Here’s why I am not overly excited.
A landmark 2020 study used chemotherapy, with or without immunotherapy, to treat early triple-negative breast cancer. Here are the pathologic complete response (no residual cancer left in the breast or regional lymph nodes) rates:
- Chemotherapy 51 percent
- Chemotherapy + immunotherapy 65 percent
I look forward to seeing continuing research with the viral approach, but for now, the new gold standard is chemotherapy plus immunotherapy.
The information I provided in this blog is for educational purposes only and does not substitute for professional medical advice. Please consult a medical professional or healthcare provider for medical advice, diagnoses, or treatment. I am not liable for risks or issues associated with using or acting upon the information in this blog.
Thank you for reading “A Cancer-Killing Virus.” One more thing:
