When you hear hoofbeats, think of horses, not zebras. — Dr. Theodore Woodward
“Can you check out this lump?” my husband asked while pulling up his shirt.
It was a Saturday morning two or three years before his cancer was diagnosed. I was sitting at my computer in the middle of editing a research manuscript. Not wanting to lose my train of thought, I hoped the interruption would be short.
“Sure, where is it?” I replied looking up from my computer.
“In my chest. Here. Under my nipple,” he said.
As an obstetrician-gynecologist, I had done thousands and thousands of breast exams on women in my career. If anything, I prided myself on a low threshold to refer women for evaluation of breast masses and biopsy.
I examined the lump, which was small, round, and smooth near the nipple. It moved freely underneath my fingers. It was very, very soft.
No alarm bells went off in my physician brain. This didn’t have the tell-tale signs of a cancer. It was certainly not hard or stuck to any surrounding tissues, like a cancer might be. It felt like many other benign fatty growths and cysts that I had felt before.
“It’s nothing”, I said. “It’s probably a benign fatty growth called a lipoma that is nothing to worry about.”
I don’t recall if I examined the lymph nodes in his armpit. This would haunt me years later. I think I did. Regardless, I was not concerned by the clinical picture.
As a man, his chance of having breast cancer was very low. None of his family members had ever been diagnosed with breast or ovarian cancer, which could have pointed to a genetic risk for developing breast cancer. This made his chance of having a breast cancer even lower. The extensive genetic testing that was eventually performed came up with nothing to explain his diagnosis. In short, he had no particular reason for developing breast cancer. Other than the randomness of a lightning strike.
Even years later, I could recall the ultrasmooth texture of the lump and its small size from this exam. It moved freely between my fingers during the exam. The physical characteristics of the lump didn’t tick any boxes in my head that screamed cancer. Yet, this should not have dissuaded me from recommending that he get it formally evaluated. Any lump in the breast should be accompanied by imaging. Even in a man. I knew this.
After his breast cancer diagnosis, neither of us spoke of the day that I discouraged him from getting the lump evaluated. I was mortified by my mistake and deeply ashamed. Too ashamed to speak about it. He didn’t bring it up either until I finally mentioned it about three weeks after his diagnosis.
“I am sorry for not having you get the lump evaluated a few years ago,” I said with tears streaming down my face. When was I not crying these days? I was always crying.
He got up from his chair, came to me and gave me a hug. The tears opened into a flood. But his warm embrace told me everything I needed to know. He had already forgiven me.
“I should have trusted my instinct to make an appointment with my primary care physician,” he said.
“No,” I said. “I should have known.” I buried my face in his chest. It was easier not to face him during this conversation. The shame was so intense.
“No, no,” he said very sincerely. “It was my responsibility to get it checked out.”
Not true, I thought silently. As a physician trained to perform breast exams, the onus was on me to suggest a mammogram and biopsy. It was my professional responsibility to recommend that he get it evaluated. Why hadn’t I done it? I couldn’t come up with an answer other than that he wasn’t supposed to get breast cancer. It was too rare, and he didn’t fit the risk profile.
“When you hear hoofbeats, think horses not zebras,” a favorite medical school professor once told me. The horses were supposed to be the common medical conditions, and zebras the rare ones. I was an impressionable third year medical student, who was learning the art of medicine from the professor with whom I was seeing patients in an internal medicine clinic. I jotted down this aphorism in a small notebook, treating it as an ancient piece of medical wisdom.
After emerging from a patient room, the professor asked me to come up with all the reasons why his patient might have high blood pressure. Rejoicing at the opportunity to share my new knowledge, I jotted down a list of possibilities. The thyroid might be overactive. The patient’s adrenal gland could be producing too much cortisol. Or, the patient might have a very rare tumor that caused episodes of life-threatening high blood pressure, headaches and sweating.
“No, no, no, Kristina,” he said, throwing back his head and laughing. “The answer is right in front of you. The patient is overweight and eating an American diet with too much salt. It’s great that you are thinking of the zebras, but in practice I want you to focus on the horses.”
And so, I did. For more than two decades, I had practiced medicine by focusing on the most common diagnoses first and only later thinking of the rare ones. Male breast cancer had been something that I learned about in medical school to answer a question on a standardized test. I had never seen or heard of a patient with it. It was a mythical, theoretical disease.
Until it wasn’t. My husband was diagnosed with this zebra. Although most men with breast cancer have a genetic cause, my husband’s testing came back negative. He had no genetic mutations linked to a higher risk of breast cancer and no relatives with breast or ovarian cancer. In fact, I couldn’t think of a single relative of his that had any kind of cancer.
Why didn’t I see his lump as a possible cancer? I should have known better, sent him for an opinion, a mammogram, an ultrasound…something. They could have caught his cancer much earlier when there was a better chance of treatment. But I didn’t.
When it mattered the most, I should have looked for the zebra in my backyard.