Michael C. Soulen, MD, FSIR, FCIRSE
Professor of Radiology
Director of Interventional Oncology
Abramson Cancer Center
University of Pennsylvania
Philadelphia, Pennsylvania

David Tischfield, MD, PhD
Department of Radiology
Hospital of the University of Pennsylvania
Philadelphia, Pennsylvania

Sneha Somani, BBme
Medical College of Wisconsin
Milwaukee, Wisconsin

In collaboration with the Society of Interventional Radiology (SIR) Resident, Fellow, and Student Section, Endovascular Today presents a new series focused on dialogue between fellows and established leaders in interventional radiology (IR). For the inaugural article, David Tischfield, MD, PhD, and Sneha Somani, BBme, talk with Michael C. Soulen, MD, FSIR, FCIRSE, about his early experiences in IR and interventional oncology (IO), how he goes about conducting research, his recommendations for interventional radiologists who are just beginning their careers, and several other interesting topics. Dr. Soulen is world-renowned not only for his contributions to the field of IO, but also for his track record of training leaders in the field.

Can you give us some background about yourself and where you did your training?

Dr. Soulen: I was born and raised in Philadelphia with my parents and two siblings. My mother, Renate L. Soulen, MD, FSIR, is the last surviving female founder of both the Philadelphia Angio Club and SIR. Last year she received the SIR gold medal.

After completing my undergrad studies at Yale, I did basic research for a few years but decided I didn’t like being a lab rat, so I spent a year at a hospital as a gastrointestinal (GI) tech doing clinical research. I then went to University of Pennsylvania (Penn) for medical school. There, I met my wife, who was in the class ahead of me, and I followed her to Johns Hopkins School of Medicine in Baltimore, Maryland. After our residencies, we returned to Philly. She joined Jefferson Health, where she’s been practicing for 30 years. I did my clinical and research fellowships at Jefferson and then came on staff at Penn, where I’ve been for 28 years.

Did you always want to go into IR? What other specialties did you consider?

Dr. Soulen: No, I certainly didn’t from the beginning. At every stage, I was considering my options. In medical school, I thought about gastroenterology and anesthesia for many of the reasons I like IR: they are very procedural, the entire body becomes a laboratory to explore, and there are many exciting research opportunities. Penn had a very strong anesthesia program, but frankly, I could not stand the early hours because I am not a morning person; that’s ultimately what made me shift to IR.

How are the early mornings working out for you now?

Dr. Soulen: The mornings are not as early as anesthesia, so it’s working out alright, but I’m still not a morning person!

Can you tell us about some of the research you’ve been a part of in the past?

Dr. Soulen: I started the IO program at Penn from scratch in 1991, and in cooperation with the pharmacy and the GI oncologists, we developed a unique chemoembolization cocktail that has been the standard of practice in the United States for 20 years. I published studies on patients treated with chemoembolization for various diseases, which hardly anyone was doing at the time. Fast-forward almost 30 years, IO is a hot area that makes up the bulk of our clinical practice in terms of revenue, and we now have one of the strongest preclinical IR research labs in the country. We have developed an autochthonous rat model for hepatocellular carcinoma and have mastered survival chemoembolization in rat models. Additionally, we have several experimental protocols using in vitro cell lines and our in vivo rat model to improve chemoembolization.

Where did you find the inspiration for these research projects?

Dr. Soulen: When I started in this profession, you were expected to be a triple threat: a master clinician, a master teacher, and a master researcher. Today, that’s impossible because each of those areas has become more complex, so you have to pick and choose what you’re going to do. In building an academic career, every area of endeavor requires a mentor because no one person can be a mentor for all of these areas. When I was a fellow, I sought out the attending who, at the time, was where I wanted to be 5 years later. I would talk with him and say, “I’m struggling with this; how do I handle this issue?” I would see what my mentors did and how they handled it, and that helped guide my own career. I’ve had many mentors over the years, and you need a lot of them.

Are there any research projects that you have worked on that you are particularly proud of or that hold a special significance to you?

Dr. Soulen: Probably not any one in particular. In the early days, we were just trying to establish that IO worked and get very basic, primitive literature out there to help demonstrate that there was some available evidence. Now, we’re moving in the direction where we do IO research the way oncologists expect us to do it: preclinical studies to establish mechanism and phase 1 studies of safety and feasibility, followed by multicenter phase 2 and 3 trials to provide high levels of evidence for efficacy. Our radiation oncology colleagues run off multicenter phase 2 trials of sterotactic ablative radiotherapy and trump us in the guidelines with their higher level of evidence. Why have we never done this for percutaneous ablation? This has to change.

I'm most excited about trying to shift the ground in prospective trials, or at least multicenter analyses, and get away from single-center retrospective analyses. I'm running the first-ever investigator-initiated, prospective, randomized trial of embolization. It is a global 20-center trial looking at embolization of neuroendocrine tumors to try to refine the current guidelines. The other huge project that we're working on now that I'm very excited about is called IO-CORE (Interventional Oncology Clinical Outcomes Registry), which is a joint Society of IO–SIR effort to create a global registry for all IO procedures. Not only will we have a clinical trials network, but we'll also have a global registry to help validate the procedures we do.

What were some of your biggest challenges, and how did you overcome them as you were pursuing this work?

Dr. Soulen: In the beginning, it was getting people to accept us at all. For example, when I first got to Penn, I was referred for my very first chemoembolization. I called the head of GI oncology, who was a well-known, established physician, and asked if he would admit this patient. His response was, “Why would I admit a patient that you're treating?” We had no help. I wouldn’t say that the oncologists or the surgeons were adversarial to us, but they weren't helpful because they didn’t believe in us and we had to prove ourselves. Once we showed our value, then doors opened up quickly. Getting that message across was one of the biggest challenges.

What do you think is the biggest mistake that you see student, residents, and fellows making when they are trying to assemble a research project?

Dr. Soulen: I don't know if there's one big mistake, but there are essential elements to emphasize. You need to find the right mentor and get past the illusion that you can do it yourself, because you cannot. Everyone needs a team where each member contributes unique skills to achieve the goals of a project. That's where your mentor helps you. You also just have to work hard. The bottom line is that no matter what field you're in, one essential element for success is hard work. Working hard beats being smart. Finally, you have to have resilience for obstacles and failure, so when you hit roadblocks, it doesn't take the wind out of your sails.

In your opinion, what is the most exciting thing in the future of IR?

Dr. Soulen: Something that is really exciting and intriguing is lymphatic intervention. The breadth of applications for lymphatic intervention range from treating septic shock to AIDS; it’s amazing. At first, we were just plugging leaks from surgery, and now we're treating diseases like protein-losing enteropathy, cirrhotic ascites, and plastic bronchitis. At Penn, we are collaborating with physicians who perform chimeric antigen receptor T-cell therapy. The applications of lymphatic intervention are astonishing.

How did you find the best way to combine your clinical interests and research interests?

Dr. Soulen: My advice is to find the research where you are. As a resident, the opportunities were in body imaging; as an IR fellow, it was biliary interventions; and as an attending, it became cancer. The clinical work drove the research. I’ve done lab work, and I’ve done animal work with rabbits, rats, and pigs. I do clinical trials, which are very important. We also do population studies. For instance, hepatocellular carcinoma is horribly underdiagnosed in the United States because compliance with screening guidelines is so poor. We designed an electronic medical records intervention incorporating both physicians and patients to improve screening compliance, diagnosis for those with positive screens, and treatment for those diagnosed. It’s a screening through treatment intervention across the electronic medical records at a population level of 450,000 lives. You need to cast a wide net across the research spectrum, but for me, they all tie back to cancer in some way.

What do you think has contributed most to your current success, in addition to great mentors?

Dr. Soulen: For me, a lot of it is being part of Penn because it’s an amazing milieu for academics where the medical school and the hospital are integrated within the main campus. The opportunities for building relationships are phenomenal. Many of my research collaborations have happened by chance through unrelated relationships, such as sitting on a hospital committee or advising students who happened to be familiar with another person’s work. Penn is an easy place to build expert teams. When I was hired, they told me that Penn was like a culture medium, all you have to do is put out ATP and you will grow.

If you had a chance to redo any part of your training or the path that you took to IR, what would you change?

Dr. Soulen: Everything I did paid off for the next thing I did. There was some uncertainty along the way—I did basic research after college because I had zero interest in medicine as an undergrad. Although I became bored, I learned research skills that served me well later in life. The fact that I was able to do a research fellowship was key. That is less common now, and the reality is that if you want to go into an academic career, you have to do a research year, wherever that fits in. Some do an MD/PhD program, some do Howard Hughes Medical Institute years after medical school, and some do a master’s program. But sometime before you become an attending, you need a productive year of research if you want to get hired as a faculty member. It’s different than in my generation when we got hired out of fellowship and had to go for it.

How do you balance the demands of research, clinical duties, and teaching—the so-called triple threat?

Dr. Soulen: That’s a task that used to be easy and now is difficult for everyone. The biggest challenge is getting the clinical and research balance to be successful. The model has to change from the individual being the triple threat to the IR division as the triple threat. A big division can delineate the clinical track people, whose job it is to crank out cases and train students, residents, and fellows. Then you have the research team, who get 40% to 50% research time. It’s a tough sell; even in our department, it’s hard to get that culture to change.

What is your advice to budding physician-scientists for achieving work-life balance?

Dr. Soulen: Most people know the parable of the rocks in the jar. A professor fills a jar with rocks and asks, “Is the jar full?” Then he pours in the gravel, the sand, and the water. He says, “What’s the moral of the story? You have to put in the big rocks first.” It is really all about communication and time management. You have to identify the “big rocks,” such as your career, spouse, children, and yourself. You have to take care of yourself and you always end up coming last. Work will suck away your life if you allow it to. You have to take vacation with your family. So many of my junior partners do not take all of their vacation time. With my wife and I both juggling physicians’ schedules, the way we handled it was with two giant calendars in the kitchen. We had a calendar for the entire year, and we would put in all the time we would take off and all of the work-related travel. The most important was the monthly calendar. Everyone’s meetings, parent-teacher conferences, children’s activities, yoga, church, whatever we did was on there, all color coded so even when the kids were little, they could tell if mom or dad was on call or away. Your children will live lives of uncertainty. They have physician parents that have insane and irregular schedules, which is okay as long as they know what to expect. Another important aspect is date night. You have to regularly schedule adult time with your spouse or partner, even if it is just going around the corner for pizza. Otherwise, careers and children consume all of your energy, and after a time, a relationship can suffer. You have to preemptively plan literally every single week so that work doesn’t take over. At the end of the day, if life isn’t on your schedule, you won’t have one.

Do you have any other advice to trainees hoping to pursue careers as clinicians and researchers?

Dr. Soulen: For those applying to residency, you are at an age where most of you are not geographically constrained. As such, you should go to the biggest and most diverse place you can. A big program with multiple practice environments broadens your education so much. Wherever it is, it’s 100% worth it. For those applying for a fellowship, you may be looking at where to settle down and get a long-term job, especially if you’ve gotten a house or you’re married or have children. Those are very practical social reasons that drive what you do at that time. It’s also where the work-life balance comes in. You may be prioritizing your life over career, but that’s appropriate at a fellowship stage.