9:00 a.m. The infusion room smells of hand sanitiser and warm blankets. Your sister settles into chair 14 with a paperback she never finishes.

She calls her diagnosis "the triple-positive special". Her cancer feeds on hormones, and it also carries too much of a protein called HER2, which makes cells grow fast. It has spread to her bones.

For years, chemotherapy has been the starting point for HER2-positive cancer. This year brought two signs that this is changing. One is a small, hopeful study. The other is a new standard of care.

Two changes, side by side
No chemo at the start (Mount Sinai) For HER2-positive cancer that feeds on hormones and has spread. A small early study of 28 patients.
Enhertu before or after surgery For HER2-positive cancer that hasn't spread. Approved in the U.S. in May 2026 after two large trials.

Chair 14: treatment without chemotherapy

At Mount Sinai in New York, doctors tried four drugs and no chemotherapy on women like your sister. Two were pills: one cut off the cancer's estrogen, and one slowed its growth. The other two, given by IV, blocked HER2.

Nearly every woman's cancer shrank or held steady at six months. On average, it took almost two years to start growing again.

One detail makes this less new than it looks. The headline went viral in August, but the result was first shown at a conference in December 2023. It took almost three years to reach your sister's group chat.

11:30 a.m., chair 15

The woman in the next chair is younger, and her cancer hasn't spread. She is having Enhertu before surgery. It works like a guided missile: an antibody finds HER2 on the cancer cell and releases chemotherapy inside it.

For her, this means skipping doxorubicin, the bright red chemotherapy nurses call "the red devil". She still gets some chemotherapy, just less, and more of it is aimed at the cancer.

2:00 p.m., the catch

Your sister's blood test comes back low. "No chemo" doesn't mean no side effects. One of the pills lowers the white blood cells that fight infection. In the study, nearly half the women had a serious drop at some point.

The study was also small, with nothing to compare it against. The researchers say a larger trial is needed before this becomes normal care. Still, it gives your sister a fair question for her doctor: does she have to start with chemotherapy, or is there a trial that tries something gentler?

By four o'clock she has finished chapter nine. The trial number is written on the back of her appointment card.

Questions readers ask

Is Enhertu the same as Herceptin?

No. Enhertu contains the antibody from Herceptin, with chemotherapy attached, so one can't replace the other. Enhertu can inflame the lungs in some people, so report any new cough or shortness of breath quickly.

What should I do if I get a fever during treatment?

If your treatment lowers your white blood cells, a temperature of 38 degrees Celsius or higher is an emergency. Call your cancer centre's after-hours line or go to emergency right away. Don't wait for morning.

Can I get these treatments in Canada?

All four Mount Sinai drugs are sold in Canada, but the combination isn't standard care, so it would usually mean joining a trial. We couldn't confirm Canadian approval for Enhertu's new uses. Ask your oncologist.

This article is for information and does not replace advice from your cancer care team.

Sources

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