Ablation for Lung Tumors: An Interview With Constantinos T. Sofocleous, MD, PhD
Editor's note: View video of this interview here.
At the 2015 Symposium on Clinical Interventional Oncology, part of the International Symposium on Endovascular Therapy, Constantinos T. Sofocleous, MD, PhD, of the Memorial Sloan Kettering Cancer Center participated in presentations on lung cancer ablations. Interventional Oncology 360 met with Dr. Sofocleous for an update on ablation therapy for lung tumors.
Q: Has lung ablation changed over the last year?
A: I would not say it has changed much in the last year. I would say that is has changed a lot over the last 5 years. We certainly have many more gadgets and more tools. We have been able to use a larger variety of energies. We are using more microwave and cryoablation than we were 5 or 10 years ago. That gives us the ability to treat tumors that previously were hard to treat with radiofrequency, because it times out and has issues transmitting the heat in lung surrounded by air. Microwave and cryoablation are much 
more efficient at killing tumor in this situation. The difference is that our colleagues from radiation oncology have presented in the last 5 years very compelling results that are very close to surgical results, especially for primary lung cancer, and interventional oncology publication is lacking in that. We need a lot more work to prove that ablation can be on the same footing as these two modalities, or at least with radiation therapy, as alternatives for primary lung cancer.
For metastatic disease I think we still have a competitive edge when it comes to both microwave and cryoablation because in the metastatic setting you anticipate that the patient will have more metastases as the patient lives longer and longer. It’s much more important to preserve the lung, and radiofrequency has that advantage even over radiation, because with radiation you max out on dosage or the patients develop postradiation pneumonitis, so although they don’t stick the lung with pneumothorax (even though sometimes they need a seed from us so they even have the pneumothorax risk), I think that long-term toxicity is favorable for percutaneous ablation especially in the metastatic setting.
A: Surgery has a significant impact on the body. It requires thoracotomy. Even for a small surgery they must cut and retract tissue until they reach the tumor, and the down time is much longer. You will always need a chest tube; it will be at least a couple of days if not a week in the hospital depending on the extent of the surgery. And you must be able to be resected. So from the beginning if there’s a patient who is borderline in respiratory failure, then it’s questionable whether he’ll be able to tolerate the surgery and be able to function normally without requiring oxygen and so forth.
The other thing is that if you expect that this is a disease that will come back, then the rationale of giving them the most aggressive treatment is not quite there if you expect there to be a high rate of recurrence. The ablation advantage is that it’s minimally invasive, the down time is a day if that – many patients go home the same day especially if they don’t have a pneumothorax. If they do have a pneumothorax, it’s something we treat right away on the table, and maybe they will stay in the hospital with a much smaller chest tube, which is not really an incision, it’s a hole smaller than the width of a pencil. So they will have a small tube for 1 or 2 days after the procedure and they will go back to their normal activities within a week, so the down time is much less than it is with major surgery.
Q: What are your methods for patient selection?
A: One thing with ablation is that you have to be able to provide an ablation that will cover the entire tumor and create a sufficient ring of cell death around the tumor and therefore eliminate the chance of local failure and future recurrence. So far the technologies seem to all do that very well in lesions that are under 3cm, they are well aerated, meaning they are not on the pleurum on the mediastinum. It doesn’t mean you can’t treat those, but the results are not going to be as good and your technical difficulties will be more so it’s not something you want to do when you’re starting out. It’s for an advanced provider. Basically any tumor under 3cm with well aerated lung is a good lesion for ablation as long as there is no other disease.
It’s essential to stage those patients. I strongly recommend you do a whole-body PET CT before doing the ablation to be sure that there are not lymph nodes, distal disease, or bone lesions. The last thing you want to do is to expose patients to a risk if there is no real benefit, even if the risk is low. If a patient has 10 tumors, it’s not going to be successful. You might burn the tumor and be successful, but the patient does poorly because he has 10 other tumors that need to be treated with chemotherapy.
Q: How would you describe the learning curve for an IO clinician learning lung ablation?
A: The first step is to be very comfortable with managing pneumothorax. You should be very comfortable placing a chest tube. The same goes for pleural effusion. Those are things that may happen with ablation so you need experience with that before you go to ablation. So if you are someone who is already doing a lot of biopsies in the lung, then you have an advantage over someone who might do lung ablation and has never done a biopsy in the lung.
Another thing is that you gain experience over time like anything else. I think it’s important to do 10 to 20 cases to get the lay of the land. You also need to be familiar with the machine you’re using. Hopefully you will get the support of the company of whatever machine you decide to use, and most companies are doing this very well. At this point, there are a lot of interventional oncologists, so if someone new wants to develop a practice, we’re all available by email. Also websites like Interventional Oncology 360 and Interventional Oncology Central and the Society for Interventional Radiology site enable physicians to interact. There are a lot of tools that people can use at this point.
Q: What published pieces do you recommend for reading about lung ablation?
A: If you’re talking about technique, there is a recent review by Dr. Damian DuPuy that describes different devices and how to use them in the lung. There was another by us that came out in 2014. Those give tips on techniques, devices, selection of patients, follow-up, and imaging.
If you’re interested in data, that’s different. There are data on both primary and metastatic lung cancer. Unfortunately there is not one single paper that you can read and be done. There are a few. Dr. Riccardo Lencioni had the RAPTURE trial for radiofrequency ablation. That is a good paper for starters. The group with Dr. DuPuy talks a lot about ablation with RF and the importance of size to outcomes both for primary and metastatic disease. There are a number of publications on primary lung cancer. They were all small papers, but they all point to the same important factors like location and tumor size and this is replicated with radiofrequency by us – we have a publication on that, the Japanese have many publications on that. The group with Dr. Thomas Vogl in Germany has similar publications for metastatic disease with microwave; we have similar publications on metastatic disease and radiofrequency. Dr. Alice Gillams has written extensively on lung ablation also, especially for metastiasis, and published a paper recently in CVIR.
Q: Are there any studies ongoing?
A: There is the SOLSTICE clinical trial organized by Matthew Callstrom, MD, and Thierry DeBaere on cryoablation for lung malignancies, which is something new. There are no data yet; they presented an abstract at RSNA in 2013 on the ECLIPSE trial that showed that it’s at least as safe as radiofrequency historical data. So it’s promising and I think their goal for the SOLSTICE trial is to enroll 150 patients and 200 lesions to evaluate the effect of cryoablation specifically.
Q: What are the recurrence and complication rates for ablation of metastatic tumors?
A: We think of recurrence locally, where at some point there is residual disease that failed control that was not detected for 6 months, a year, or more, and especially if you use PET you might see tumor coming back in that ablation zone. If the tumor is small and you can treat with good margins, you can have local control that is over 85%. Once the tumor size goes up, that drops dramatically. If you do a good selection, more than 3 of 4 patients will be controlled locally for the tumor you treated. In terms of developing cancer in other places of course that has nothing to do with ablation; that has to do with the biology of disease or the chemotherapy that is available, so I can’t give a bland number for the rest of the progression that a patient might have.
As for complications, the ablation of the lung in general, the overall complication really is high if you include the pneumothorax as a complication. In my mind, the pneumothorax and chest tube placement is not a complication. I consider it almost a step of the procedure. It happens in about 20% of cases and it’s very manageable and in many cases we do it on purpose to move things around. If you exclude this, then the complications are less than 10% and they include everything: bleeding, infection, pleural effusion, injury to a nerve, burning something you don’t want to burn, collateral damage, pain. Most of those are self-limiting, they don’t require any intervention or admission and they are manageable on an outpatient basis. Occasionally you may need to tap a pleural effusion or admit someone with a chest tube for 1 or 2 days. One of the rare complications that is harder to manage and rarely may require surgery is bronchopleural fistula, which is a communication of the airway with the pleura, and that’s harder to manage and may require drainage, but again it’s very rare.
Q: Any other points you’d like to add?
A: What I would like interventional oncology clinicians to strive to do is become part of a clinical team and not just place a needle but think about the disease, know the disease, read about the disease, and be part of the team that manages that disease. I favor being an expert on the disease and managing certain diseases in a group rather than being able to do everything just because you can do it.
And I hope to see you at upcoming conferences, such as the European Conference of Interventional Oncology (ECIO), led by Dr. DeBaere, which will take place in April in Nice, France, and the World Conference on Interventional Oncology (WCIO) in New York, for which I serve as scientific chair.
Constantinos T. Sofocleous, MD, PhD, is an interventional radiologist at Memorial Sloan Kettering Cancer Center. His areas of expertise include treating primary and metastatic cancers of the liver and lung using radiofrequency ablation, cryoablation, and microwave or other sources of energy as well as embolization of liver tumors.
Suggested citation: Ford J. Ablation for lung tumors: an interview with Constatinos T. Sofocleous, MD, PhD. Intervent Onc 360. 2015;3(3):E24-E27.
