Targeted Therapy? Yes, Please!

You cannot say that there is a “good” cancer to have. Because the only thing that would make the cancer that you have “good” is not having it in the first place.

But if that’s not the case, the next best thing is having a cancer with characteristics that serve as targets for drugs, enabling the use of “targeted therapy”. As described by the American Cancer Society, “Targeted therapy is a type of cancer treatment that uses drugs designed to ‘target’ cancer cells without affecting normal cells. …Targeted drugs can block or turn off signals that make cancer cells grow, or can signal the cancer cells to destroy themselves.”

Cancer treatment often means chemotherapy, but there are some targeted therapies available that are highly effective.

When talking about breast cancer, currently there are several targets possible: estrogen receptor, progesterone receptor and human epidermal growth factor receptor 2 (or HER2 [also HER-2/neu or ErbB2]). These three are the ones that your oncologist will use to characterize your tumor.

The estrogen and progesterone receptor positive (ER+ and PR+, respectively) tumors are the most common ones. According to WebMD, about 80% of breast cancer tumors are ER+ and 65% are PR+, and these tumors are treated with hormone therapy, generally tamoxifen and aromatase inhibitors (depending on the patient’s menopausal status).

HER2+ is an interesting case. HER2+ tumors contain extra copies of the gene that makes the HER2, which is thought to make cancer cells grow faster. Historically, the prognosis for HER2+ tumors has been worse than for HER2- tumors, with a greater chance of recurrence and metastasis.

At least, that was the case before the development of targeted drugs specifically for HER2, such as trastuzumab (Herceptin), pertuzumab (Perjeta) and others. These drugs don’t come without risks and are known for being potentially cardiotoxic, but they are very effective.

This is the irony. Triple-positive breast cancer went from being one of the more aggressive breast cancers to being almost “curable”. All due to targets.

This is also what makes triple-negative breast cancer (TNBC) more complex. Without specific targets to aim for, treatment of TNBC relies on aggressive chemotherapy, which can be quite effective. But without targeted therapies, TNBC still has the highest rate of recurrence and worst prognosis of all breast cancers. Researchers are furiously searching for new ways to characterize TNBC tumors for this very reason.

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We are all looking forward to the day when we can say there is a definitive cure for cancer.

But what brought on this post? I was searching on the internet for breast cancer info on HER2+ tumors and came across a provocative headline from MedicineNet.com that read, “Can HER2-Positive Breast Cancer Be Cured?” The answer to this, I assumed, would be “no” because we’re not at the point where we can say that we’re definitively “curing” breast cancer.

In addition, I’d been conditioned by my oncologist to think of cancer in terms of years of survival rather than cure.

But according to this MedicineNet article, “With recent advances in medicine, it is considered that HER2-positive breast cancer is curable.” A bold statement indeed. And one that I hope we will be making more and more.

For an article from the American Cancer Society describing available targeted therapies for breast cancer, go here.