Mr. C’s brain tumor seemed to be reaching its endgame. His wife had called frantically to report new confusion, word-finding difficulties and visual deficits that suddenly developed despite ongoing treatment. We hastily arranged for an MRI scan to confirm what we now collectively came to suspect: Cancer cells from his tumor had invaded previously unaffected parts of the brain.

Much of what is seen as a medical trainee continues to haunt you because it can never be unseen. In my 10 years as a doctor and medical student, I have been witness to inordinate human suffering and unexpected tragedies. And the emotions associated with these experiences went largely unexplored because I had constructed a mental dam over the years to contain them and to prevent their flow into my daily work as a doctor.

But Mr. C changed me. Though the long-standing medical ethos emphasized impassivity to be a virtue for physicians, I could no longer deny my emotions as I cared for him and learned his story.

His medical history was an unlucky one. Mr. C (I’m using only his initial to protect his privacy) had already dealt with two less aggressive tumors called astrocytomas in the past. Though they were treated, some residual cells were left behind. Gradually, glioblastoma, a particularly virulent and recalcitrant brain tumor, evolved from these cells. And in less than a year, this cancer had already defied the attempts of multiple drugs to shrink or contain it.

By rights, none of this was supposed to happen to Mr. C. He was 31 and statistically far too young for such a cancer. He was also “daddy” to three children ages 4, 2 and 1.

For me as an oncologist, Mr. C’s grim prognosis was difficult to swallow. For a new father, it was unacceptable.

My wife was due to give birth to our first child only weeks before I saw Mr. C in the clinic. Our son’s arrival would forever alter why my life mattered. I would occupy the privileged, ringside seat to his life, and he would need me to be his coach and greatest fan for as long as possible. This was the same seat that Mr. C was about to forever vacate for not just one child, but three.

These thoughts gnawed at my mind as I examined Mr. C and made note of all the faculties that the growing tumor deprived him of. He wanted to capture a few more quality moments of life with his kids before they were beyond his grasp. As we sat there and discussed how probable this was, I could think only of my son and how, at least for now, my time with him was promised.

At that moment, I felt something that I had never experienced before inside a patient’s room: tears in my eyes.

Before meeting Mr. C, my approach was consistent with the prevailing belief in medicine that physicians should be imperturbable. This gospel was put forth most notably by William Osler, a seminal physician who lived from 1849 to 1919 and developed the first residency training program. In a speech known as “Aequanimitas,” he told a graduating medical class at the University of Pennsylvania that “the first essential is to have your nerves well in hand . . . educate your nerve centers so that not the slightest dilator or contractor influence shall pass to the vessels of your face under any professional trial.”

It is believed that depersonalization prevents contamination of the patient-doctor relationship by emotions and ensures a commitment to objectivity. This also preserves the long-standing archetype of the infallible, unflappable and sagacious physician.

Given this context, crying is viewed as an extreme emotional behavior that evinces instability and an unsuitability to grapple with thorny matters such as disease and death. As physician Paul Rousseau noted in a 2003 article in the American Journal of Hospice and Palliative Medicine, “Crying was equated with inadequacy, personal and emotional weakness, incompetence, and unprofessional behavior.” And though there is an understanding that it may inevitably happen, crying is expected to take place alone in the isolated margins of parking lots, call rooms and stairwells.

Despite the condemnations, studies show that there are plenty of tears in medicine.

A 2009 study noted that 69 percent of students and 74 percent of interns self-reported crying for reasons pertaining to medicine. Specialists such as pediatric oncologists reported crying as part of their range of reactions to patient death. Surveys of Australian and Dutch physicians further reflect the universality of crying in medicine.

It is difficult not to expect grief to emerge from a profession whose primary challenge is to stave off death for as long as possible. And unfortunately for many physicians, this is a contest that is lost almost daily.

The sorrow that results from an unfavorable prognosis or untimely demise can be redirected, suppressed or compartmentalized, but its effects linger on. At best, it leaves you inured to further suffering, and at worst it festers, seeps into your personal life and slowly erodes your emotional resilience. As physician and writer Danielle Ofri notes in her book, “What Doctors Feel,” “With no time or space to give grief its due, burnout, callousness, PTSD, and skewed treatment decisions are a risk.”

An emotional exchange is inescapable when human beings will care for other human beings. For medical students, the possibility of such a powerful and transformative experience is what initially stirs them into applying to medical school. For me, it is an opportunity to not only show compassion for my patients but also experience life by seeing myself within them.

In medicine, we often learn the most about life from the patients who have so little of it left. My tears for Mr. C saved me by allowing a long-delayed reckoning with my accumulated years of grief. Instead of diminishing me as a physician, I am left with a more nuanced perspective on life, a greater appreciation for medicine’s fallibilities and boundaries, and a renewed commitment to my patients. Most important, I expect to be an even better father to our son now.

Tears communicate a doctor’s humanity and signal that disease is a shared experience. It is not surprising then that patients desire care from clinicians who feel their emotions deeply and that clinical outcomes are better when doctors are emotionally invested in the care they provide.

The lesson here is simple: Though we always treat our patients with stethoscopes, sometimes it is only the teary hearts underneath our white coats that will truly heal them.