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Classical Hematology: A Specialty in Decline?

November 23, 2021

November 2021

As workforce shortages persist, this ancient art is undergoing a modern renaissance.


Two factors influenced Alfred Ian Lee, MD, PhD, to specialize in classical hematology. The first was joining his father, a pathologist, in viewing blood smears under a microscope. The second was the ability to learn under Thomas Duffy, MD, professor emeritus of medicine at Yale School of Medicine.

“Dr. Duffy, one of the most legendary physicians in the history of modern medicine, taught hematology at Yale when I was a medical student,” said Dr. Lee, now associate professor of medicine and program director for the hematology/oncology fellowship program at Yale. “The way he presented hematology was indescribably elegant and lovely. He represented the perfect synthesis of pathophysiology of disease and appreciation of what it is to be a master clinician and deeply celebrate humanity in medicine.”

Seeing those things merged into one person cemented Dr. Lee’s interest in the field.

Dr. Lee’s experience of coming to classical hematology falls in line with what a recent American Society of Hematology (ASH)–sponsored survey of thousands of adult hematology/oncology fellows found: Mentorship was identified as the single most important determinant affecting fellows’ career decisions.1

“Part of the challenge is that, because there are so few providers who really declare themselves as classical hematologists, a lot of trainees and students don’t know what it is that specialists in classical hematology actually do,” Dr. Lee said. “In fact, a lot of people in medicine do not quite understand the kinds of patients we see, the diseases we specialize in, or what a life as a classical hematologist is like.”

Ariela L. Marshall, MD, a hemostasis/thrombosis specialist at the University of Pennsylvania, echoed the importance of mentorship and exposure to the field.

“I did not have significant clinical exposure to nonmalignant hematology until I had already started my hematology/oncology fellowship,” Dr. Marshall said. “I started with an intent to specialize in breast cancer and changed to nonmalignant hematology only after gaining valuable clinical exposure.”

That put Dr. Marshall into the approximately 5% of hematology/oncology fellows who go on to practice classical hematology as their primary specialty.2 The fact that such a small minority of fellows go into the specialty has lead to a supply of trained hematologists that falls far short of the demands of a growing patient population.1

Identity Crisis

Anyone newly interested in the field of hematology may notice that there are some inconsistencies in how practitioners or departments refer to the specialty. “General hematology” may refer to a practice or practitioner that specializes in all types of disorders related to the blood – malignant or otherwise.

Roger M. Lyons, MD, is a board-certified hematologist in private practice with Texas Oncology, a member of The US Oncology Network. Dr. Lyons refers to himself simply as “a hematologist.” Earlier in his private practice career, he treated mostly patients with acute leukemias, but he has “partners to do that now,” he told ASH Clinical News. Instead, he devotes more of his time to treating nonmalignant disorders and estimated that there are about 20 to 25 other practitioners with this focus nationwide within The US Oncology Network.

The terms “benign hematology” or “nonmalignant hematology” have been widely used as well. Dr. Marshall believes these are the most widely understandable to describe the specialty. However, the field is seeing another recent shift toward referring to the field as “classical hematology.”

“‘Benign hematology’ is the term that we historically used at Yale, but the problem is that these disorders are often not benign for patients, and many can be debilitating or life-threatening,” Dr. Lee said.

According to Dr. Lee, classical hematologists see patients with a wide variety of disorders such as sickle cell disease, thrombosis, anemias, bleeding disorders, hemoglobin disorders, thalassemia, autoimmune hematologic diseases, and other rare diseases.

“These terms are all synonyms and none of them are really perfect,” said Robert A. Brodsky, MD, professor of medicine and the director of the Division of Hematology at Johns Hopkins School of Medicine in Baltimore.

“Some people would even lump certain malignant hematologic conditions – like leukemia – under the classical hematology umbrella. What they all definitely mean, though, is no solid tumors,” said Dr. Brodsky, who is also the 2021 ASH Vice President.

There has even been a shift from the mentality of the “old guard” of hematologists – about a quarter of whom stated in 2015 that they were considering retiring in the next five years3 – and the new.

In hematology, there is a deep-rooted appreciation of clinical mastery, pathophysiology, and clinical reasoning, Dr. Lee said. “A lot of the older figures in classical hematology – master clinicians who published great works – focused on the physical exam, blood smears, and diagnostic techniques that formed the basis of the field,” he said. “Those aspects should never go away, but just like in the field of oncology, there have been a lot of major molecular advances in classical hematology in recent years.”

This is a huge new element taking the field by storm, Dr. Lee said, and these cutting-edge advances need to be captured when shaping the future of the field and attracting new talent.

Why the Shortage?

Several years ago, ASH began funding a study to look into the status of the hematology workforce, with the hope of understanding factors that contribute to fellows’ plans to enter hematology-only careers. In addition to a lack of mentorship, the research identified several other factors influencing these plans, including a lack of exposure to hematology patients in medical school or fellowship and lack of exposure to hematology research experiences.2

Respondents who were seeing hematology outpatients during their current fellowship year were five times more likely to say they had plans to enter hematology-only careers. Those who reported participating in a hematology research project were almost seven times more likely.2

However, exposure to a mentor or senior faculty directly influences the likelihood of exposure to hematology patients and research.

“Without seeing us as role models, it is difficult for trainees to know what life would be like as a classical hematologist,” Dr. Lee said.

“Even if a large number of trainees wish to pursue training and research in nonmalignant hematology, there are limited numbers of potential mentors,” Dr. Marshall said. “I think that, with the current era of virtual connections, opportunities for mentorship can be expanded so that those with an interest in nonmalignant hematology can seek mentors outside their own institutions.”

Other factors may dissuade trainees from the specialty, such as the prevalence of burnout in the field, lack of research funding, and perceptions about job availability and earning potential.

“There is definitely a problem with National Institutes of Health [NIH] funding as it relates to classical hematology,” Dr. Brodsky emphasized. Funds for hematology-focused research have been split across three NIH agencies and, across all three, hematology is not always the top priority, he explained.

First, there is a hematology branch of the National Heart, Lung, and Blood Institute, but Dr. Brodsky said the bulk of research funds in this branch go to cardiology and pulmonology. Next, someone studying malignant hematology or associated issues can pursue funding through the National Cancer Institute. Finally, studies related to nonmalignant hematologic topics such as iron physiology can be funded through the National Institute of Diabetes and Digestive and Kidney Diseases.

To address the limited funding for hematology-focused research out of the NIH, ASH has committed $3 million annually to support research in blood diseases.

On top of the limited research funding, hematology training programs are also highly competitive. Every institution has a limited number of slots available to fellows and hematology/oncology slots are among the most competitive. However, hematology-only slots are even tougher, Dr. Brodsky said.

Dr. Brodsky is speaking as head of one of the few freestanding hematology divisions left in the United States. “We have two slots a year that train in benign and malignant hematology and we have more than 100 applicants,” he said. “If you compare the number of available slots and applicants in hematology to those in solid tumor oncology, the ratio is much more competitive.”

Yale’s fellowship program started a hematology-focused track last year and, already, Dr. Lee said, interest in hematology-focused training has grown.

Finally, with most medical students graduating with more than $250,000 in debt, future earning potential could be a major influence on the specialty they choose.4

“Thankfully, in most academic settings, salary is generally similar for both benign and malignant hematologists as long as they are within the same division or department,” Dr. Marshall said. “In private practice, however, those who specialize in nonmalignant hematology may have a lower salary because the most highly renumerated portions of practice are things like chemotherapy.”

Even within academic settings, though, Dr. Marshall admitted that work relative value units (RVU) and bonus structures could still create some salary inequities.

When Dr. Lyons left academia for private practice, he did so because he could not afford to feed his family, he said.

“I can’t speak to the differences in salary now, but it wasn’t for me,” Dr. Lyons said. “The academic setting may be perfect for people who want to have downtime for research or do not want to be on night calls. It is a different lifestyle that didn’t work for me, or for a fair number of my partners.”

Dr. Lyons explained that he wanted to spend his time seeing patients. He has stepped back in recent years, but he previously spent an estimated 4.5 days per week seeing patients and 2.5 days per week doing administrative work and clinical research.

“I was by the hospital every day on the weekdays and on the weekend call schedules,” Dr. Lyons said. “I would have anywhere from five to 15 patients in the hospital and see an average of 20 patients in the clinic. They were very busy days.”

If Not You, Then Who?

Classical hematologists may specialize in one or a few conditions or see patients with all “nonmalignant” disorders but, given the shortage of these specialists, there are only a few practitioners left seeing a disproportionately large number of patients.

“Our field intersects with every other field of medicine because we operate in the realm of everything that has to do with blood,” Dr. Lee said.

This can include different conditions or diseases, medications, surgical interventions, and technologies that affect the blood. It can also include patients referred to hematologists for rare or unknown diseases in which the only indication of a problem may be abnormal blood counts.

Dr. Brodsky estimates that more than half of the patients who he sees at his hematology clinic are from outside of the Baltimore area of Maryland, Virginia, Pennsylvania, and Washington, D.C. In addition to patients who visit Johns Hopkins, Dr. Brodsky is often called upon to help in the remote management of patients at centers lacking the expertise to treat certain hematologic disorders.

To address the clinical demand, centers that specialize in classical hematology must often decline to see a large number of the patients who are referred to them.

“Even in a place like Johns Hopkins, we have to send many patients that are referred to us out because we cannot possibly take care of them all,” Dr. Brodsky said. “We try to focus on the cases of interest or those that are the most complex, but if someone is referred for something like a deep vein thrombosis or pulmonary embolism, they might get referred back to a general internist or a hematologist/oncologist.”

Dr. Marshall agreed that classical hematologists cannot possibly care for all the patients with hematologic disorders.

“Patients with specific conditions like sickle cell disease and thalassemias are often cared for only by nonmalignant hematologists, but patients with conditions such as thrombosis are often cared for by general hematologists, cardiologists specializing in vascular medicine, or general internists,” Dr. Marshall explained. “Patients with bleeding disorders manifesting as menorrhagia may be cared for primarily by OB-GYN providers who have experience in such conditions.”

Advanced practice providers (APPs), such as nurse practitioners and physician assistants, are also helping to address demand. Earlier this year, Dr. Marshall discussed the role of APPs at a meeting of ASH’s recruitment and retention working group. In her presentation, she discussed results from a workforce study published by ASH in 2019, in which 675 practicing hematologists and oncologists reported that APPs were assisting with managing palliative care, conducting hospital rounds, managing patients with low complexity benign hematologic disorders, and performing invasive procedures such as lumbar punctures. Notably, in this study, community physicians who worked with APPs reported fewer burnout symptoms.

Finally, incorporation of a systems-based hematologist may also help ease the burden on hematology-only specialists. A systems-based hematologist is employed by a hospital or health system to try to optimize individual patient care and the overall system of health care delivery as it relates to hematologic disorders. Early research shows that the new subspecialty can be successful, but it cannot be the sole solution to the shortage.5

“In some settings, having a systems-based hematologist may be the best a system is able to do, especially in places with a small hematology/oncology division,” Dr. Brodsky said. “It is not the best long-term solution for the field, though.”

Righting the Ship

Dr. Brodsky believes one of the easiest ways to start addressing the workforce shortage is with training programs.

“Many people want to focus on hematology rather than solid tumor, but that option is just not available at most academic programs in the country,” Dr. Brodsky said.

Instead, most fellowship programs are combined hematology/oncology programs run by cancer centers. These centers have a huge volume of patients with cancer, and fellows are often naturally steered toward the care of patients with solid tumors rather than those with hematologic diseases.

“A lot of reimbursement to these centers relates to administering chemotherapy,” Dr. Brodsky added. “It is much more lucrative for hospitals and hospital systems to see large volumes of solid tumor patients then it is to treat members of the sickle cell population or the hemophilia population.”

The hematology/oncology fellowship program at Johns Hopkins introduced a single-board hematology track in 2005. At 10 years, the program demonstrated “high retention in academic benign and malignant hematology, both in terms of clinical and research focus,” according to a review of its progress.6 Initially, candidates for the program were selected based on their expressed interest during the interview. Later, an option was added to the Electronic Residency Application Service allowing candidates to independently apply to the hematology track. In 2018, of 414 applicants to the hematology/oncology fellowship program, 51 applied to hematology-only track and 26 candidates expressed an interest in benign hematology, contradicting “the perceived lack of enthusiasm for hematology.”

To help increase the number of hematology/oncology fellowship programs that prioritize training and careers in hematology, ASH committed $19 million to create its Hematology-Focused Fellowship Training Program. This program will fund the creation of 10 new innovative hematology-focused fellowship tracks within existing hematology/oncology training programs and will fund one or two new fellows in each program for five years at each institution. The ASH program is expected to produce 50 new academic hematologists by 2030.7 The deadline for program proposals is November 15, 2021, and the institutions selected for the program will be announced in March 2022.

Some specialists are also pushing for a separation of hematology and oncology fellowship training because of the complexities of both fields.

“We are in a historical moment,” Dr. Brodsky said. “When I was in training, there were eight to 10 chemotherapy drugs. For anticoagulation, there was aspirin, heparin, and warfarin.” Now, there are more than 15 anticoagulants, and numerous antiplatelet agents, with more coming. And, “as far as cancer therapeutics go, forget it!” Dr. Brodsky said.

“It is very hard to stay current in both fields,” he acknowledged. “With hematology and oncology, you can’t be good at both.”

Dr. Lyons believes that refocusing efforts on growing the number of hematology-specific training programs could benefit the field, but he was hesitant to endorse the idea of eliminating combined fellowship programs.

“Eliminating the combined programs might remove hematology training from the hematology/oncology fellowships,” Dr. Lyons said, “but I worry that these trainees would think they know a lot more than they really do when they end up with a patient with an unusual coagulation issue or autoimmune disorder.”

ASH’s hematology-focused training program is a good start, but it is unrealistic for every hematology/oncology program to have single-track hematology training, he added.

In fact, Dr. Marshall thinks keeping the training combined may help expose others – as it did her – to a field they might not otherwise consider.

“As long as we have a shortage of benign hematologists, it is good for hematology/oncology fellowship programs to ensure that they have appropriate education,” Dr. Marshall said. In that way, they can “ensure that their fellows are able to manage these conditions if they choose to enter a practice where they are responsible for both benign and malignant hematology conditions.”

However, she noted, “a hematology-focused fellowship training program could offer those who already know they wish to pursue a career in benign hematology the chance to focus their clinical training and research only in their specific field of interest.” This would allow for the development of close relationships with mentors in the field.”

Staying Focused

Increased attention and focus on the pending classical hematologist workforce shortage should be a priority for the field.

“We have a shortage of hematologists who are comfortable treating the more complex benign hematologic diseases and it is a problem across the country,” Dr. Brodsky said.

Hematology is a big field. For a quantitative demonstration of exactly how big, Dr. Lee estimated that 30 to 60% of patients seen at many cancer centers have benign hematologic disorders.

“This leaves us in a really interesting state, in which the existing supply of hematologists and oncologists in the United States cannot meet the growing clinical demand for specialty care of patients with benign hematologic diseases,” Dr. Lee said.

“We need more people trained in this specialty and we need more training programs to do that,” Dr. Brodsky added. “These diseases can be very acute and these patients need to be seen quickly. We have seen amazing advances in these diseases. It is incredible how treatable many of them are if they are diagnosed and managed appropriately.”—By Leah Lawrence


  1. Sharma D, Wallace N, Levinsohn EA, et al. Trends and factors affecting the US adult hematology workforce: a mixed methods study. Blood Adv. 2019;3(22):3550-3561.
  2. Masselink LE, Erikson CE, Connell, et al. Associations between hematology/oncology fellows’ training and mentorship experiences and hematology-only career plans. Blood Adv. 2019;3(21):3278-3286.
  3. ASH Clinical News. Adapting to Changes in Practice-Based Hematology. May 15, 2015. Accessed October 4, 2021.
  4. Association of American Medical Colleges. Physician Education Debt and the Cost to Attend Medical School: 2020 Update. Accessed October 4, 2021.
  5. May JE, Irelan PC, Boedeker K, et al. Systems-based hematology: highlighting successes and next steps. Blood Adv.2020;4(18):4574-4583.
  6. Naik RP, Marrone K, Merrill S, et al. Single-board hematology fellowship track: a 10-year institutional experience. Blood. 2018;131(4):462-464.
  7. American Society of Hematology. Hematology-Focused Fellowship Training Program. Accessed October 5, 2021.


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