How One Test Changed The Course of My Breast Cancer Journey

Not every woman with early-stage breast cancer needs chemotherapy. Genomic tests like MammaPrint are helping doctors determine who does.

When I was diagnosed with Stage IIA breast cancer in late 2017, I thought the hardest decisions had already been made for me. There is a strange kind of arithmetic that happens after a cancer diagnosis. Every decision suddenly carries impossible weight. Lumpectomy or mastectomy. Chemotherapy. Radiation. When survival is all you can think about, instinct tells you to say yes to everything. That was certainly how I felt.

When my team of doctors at Makati Medical Center mentioned a genomic test called MammaPrint while we were planning my treatment, I must admit the idea flew right over my head. I was navigating unfamiliar territory. I had never heard of genomic testing. I knew about chemotherapy and radiation, and I had already accepted that they would be part of my treatment.

There were other decisions to make first. After discussing my options with my doctors, I chose a lumpectomy, which removes only the tumor and a margin of healthy tissue, instead of a mastectomy, which removes the entire breast. I told them if cancer had spread to my lymph nodes, chemotherapy would probably be unavoidable. If the nodes were clear, I would consider MammaPrint.

Thankfully, my lymph nodes came back negative, and I decided almost immediately to proceed with MammaPrint.

At that point, I weighed barely 90 pounds. I had always been petite, but the stress of the diagnosis had caused me to lose even more weight. My doctors were concerned that chemotherapy might be especially difficult for my body to tolerate. If there was a reliable way to determine whether I would truly benefit from it, I wanted to know.

The process itself was surprisingly simple. A tissue sample from my tumor was sent through the local MammaPrint representative. I remember standing in line at the bank to wire USD 3,500 to Singapore, wondering whether I was paying for peace of mind or taking a costly leap of faith. From there, the specimen was forwarded to Agendia’s laboratory in the Netherlands for analysis.

About a week later, my oncologist received the results by email. The report classified my tumor as “low risk, Luminal A,” and concluded there was “no expected benefit from chemotherapy.” Based on the biology of my tumor, my five-year chance of remaining free from distant metastasis was estimated at 93 percent with endocrine or hormone therapy (oral medication) alone. Adding chemotherapy increased that figure to 99 percent, a difference that was not considered significant enough to justify months of treatment.

That single email changed my treatment plan.

Instead of adding chemotherapy to my treatment, I underwent 33 sessions of radiotherapy, followed by years of hormone therapy (tamoxifen). Today, more than eight years later, I remain cancer-free.

Most women are familiar with genetic tests such as BRCA, which look for inherited mutations that increase a person’s lifetime risk of developing breast cancer. MammaPrint is different. Instead of predicting a person’s risk of developing breast cancer, it helps predict whether an existing cancer is likely to return.

MammaPrint is designed for women with early-stage breast cancer, generally Stage I or II, where the biggest question after surgery is whether chemotherapy will provide enough benefit to justify its risks. It is one of several genomic tests, alongside Oncotype DX, EndoPredict, and Prosigna, that reflect the shift toward precision medicine, tailoring treatment to the biology of each patient’s tumor instead of relying on a one-size-fits-all approach.

One of the biggest misconceptions about breast cancer is that more treatment is always better treatment. Modern oncology aims to treat cancer intelligently, not simply aggressively. For patients whose tumors are biologically less likely to recur, avoiding unnecessary chemotherapy can spare them months of debilitating side effects without compromising their outcome. Conversely, genomic testing can also identify patients who would benefit greatly from chemotherapy, allowing doctors to recommend it with greater confidence. 

Of course, genomic testing is not a magic answer. Cost remains the biggest barrier. Genomic tests are expensive and generally not covered by insurance in the Philippines. There is also no guarantee of a low-risk result. For some patients, chemotherapy will still be the clearly recommended course of treatment. For others, doctors must weigh the genomic test alongside other clinical factors. It is another piece of the puzzle, not the entire picture.

Would I recommend it to every woman diagnosed with breast cancer? Not necessarily. Every diagnosis is different. Every tumor is different. Every person’s financial circumstances are different.

But I do believe every eligible patient deserves to know that the conversation exists.

For me, MammaPrint was money well spent. It gave me something every newly diagnosed cancer patient longs for: clarity. It allowed me to make one of the biggest decisions of my life based not on fear, but on the biology of my own cancer.

During Breast Cancer Awareness Month, we rightly encourage women to get screened and know their bodies. Awareness should also include knowing that breast cancer treatment is becoming increasingly personal. Sometimes medicine is not about doing more. Sometimes it is about knowing enough to do exactly what is needed, and having the confidence to trust that decision.