Katherine Thornton, MD

Katherine Thornton, MD

Expert Perspectives
Katherine Thornton, MD

 

Clinical Insights in Soft Tissue Sarcoma

Headshot

Katherine Thornton, MD

Practice Community
Boston, Massachusetts
Practice Niche
Sarcoma
Hospital and Institutional Affiliations
Clinical Director, Center for Sarcoma and Bone Oncology, Dana-Farber Cancer Institute

 

Question

What are the key factors that indicate a patient with soft tissue sarcoma (STS) is a good candidate for surgery?

Answer

One of the things we look for in regards to whether a patient should go for surgery is, first and foremost, is the tumor localized. Especially if we are considering a primary curative surgery, the fact that something has not metastasized will be one of the main questions that we are considering. If it has metastasized, one of the other considerations is whether the patient is symptomatic from the tumor. Even if it has metastasized, if it is causing the patient pain or negative symptoms, we might still consider a primary surgery. Whether it is low grade or high grade, we would still want to remove the primary tumor because even low-grade tumors would have the possibility of metastasizing. We’re going to always try, if at all possible, to get the tumor out of there. Clearly, the location of the tumor — location, location, location — is important in sarcoma oncology. If this is an extremity sarcoma versus a retroperitoneal sarcoma that’s wrapped around the aorta, that may obviously be more challenging.

Question

What factors indicate that a patient is not a good candidate for radiation or surgery?

Answer

A difficult area that is surrounding or involving a vital organ can become challenging. For example, the heart is a very difficult area to perform surgery on. This also eludes to the issues with radiation therapy as well. Somebody who has a tumor that is very diffuse, where you can’t really pinpoint one specific location for radiation, that can be challenging from a radiation standpoint. We may avoid using radiation is if the tumor is very low grade and can be easily removed with surgery, given the long-term possible toxicities. But, if there is a high-grade tumor with a high possibility for local recurrence, then that is a situation where we would want to use radiation.

Question

What are the treatment options for patients who are not good candidates for radiation or surgery?

Answer

That’s when we turn toward systemic therapy. This comes down to what specific type of STS we are dealing with. More and more these days, treatment is very histology-driven. One type of sarcoma may prompt me to choose one particular chemotherapy regimen versus another type of chemotherapy. Additionally, beyond histology, the tumors genetic profile will help drive treatment options. We have seen this in recent “tumor agnostic” US Food and Drug Administration approvals recently. We’re always looking to clinical trials for patients, both in the upfront setting and in the recurrent or metastatic setting. When I am meeting somebody for the first time, I’m always trying to figure out, is there an appropriate clinical trial that might give the patient a good option for disease control or improvement over existing standards of care? Soft tissue sarcoma is not really one disease, it is over 50 different diseases. The type of soft tissue sarcoma that a particular patient has is what helps drive decision-making.

Question

What are the side effects that most frequently occur when patients are being treated for soft tissue sarcoma? How do you counsel patients and manage these side effects?

Answer

It depends on what kind of regimen is being utilized. What type of chemotherapy or targeted therapy we’re using will dictate what kind of side effect profile that we incur. If we are using more traditional cytotoxic types of chemotherapy like anthracyclines or taxanes, we’ll encounter myelosuppression with the possibility of neutropenic fever, or we’re concerned about neuropathies with the taxanes, fluid accumulation and weight gain from the steroids that we use with some of the chemotherapies. There is also general fatigue and malaise. Also, mucositis can occur with drugs such as doxorubicin. One toxicity that I’ve been encountering a fair amount lately is radiation recall, which can lead to skin toxicity when a patient has had prior radiation therapy. When a patient receives chemotherapy later in their treatment, it can heighten the previous effects of the radiation therapy and can be debilitating. The side effect profile for targeted therapies shifts a little bit. For example, pazopanib is approved for soft tissue sarcoma in the second- and third-line setting. Some of the side effects that we see with that treatment are hand-foot or palmar-plantar erythrodysesthesia, which is a different kind of a toxicity compared with what is typically seen with cytotoxic chemotherapy.

I try to counsel my patients ahead of time before they get these side effects so that they are tuned in and able to me know if they’re having a hard time so that their care team can intervene before it becomes a big problem. In these cases we can either reduce the dose of their chemotherapy or stop the therapy altogether to give them time to rebound. I find that counseling patients so they are educated and know what to expect can be really helpful in preventing some things from occurring. For example, I always tell my patients in regards to mucositis to chomp on ice, which was something that one of my early nurses taught me. I think it really helps, it helps vasoconstrict the vasculature in the mouth and makes it harder for the chemotherapy to be distributed to the oral mucosa and that can be really helpful for patients.

Question

Are there any new or upcoming data that you are excited about for the treatment of patients with soft tissue sarcoma?

Answer

There are a lot of things on the horizon that I feel are very promising. There has been a lot reported recent conferences, such as the 2018 American Society of Clinical Oncology Annual Meeting, on the use of NTRK inhibitors. I’m excited about the direction that those are heading in. Unfortunately, they only help a small percentage of sarcoma patients, but when patients respond the responses can be quite dramatic. Immunotherapy has had a variable response in the sarcoma world. I am excited about the ongoing efforts to explore which of our patients will derive benefit. Determining the answer to that question will have a huge impact in the field of sarcoma treatment.

Question

Are there any other points that you think are important to make for oncologists who are treating patients with soft tissue sarcoma?

Answer

Oncologists who are treating patients in the community should refer their patient to be seen at a higher volume sarcoma center if logistically feasible. There are a lot of clinical trials that patients might be eligible for. Additionally, having expert pathology review is vitally important for our patients because we find that we will change the diagnosis many times based on the expertise of our soft tissue sarcoma pathologist. That can really affect an individual’s treatment in the long run. With a referral, I will speak to the community oncologist and make recommendations. If a patient was going to proceed with something that would be considered a standard of care, a patient can get that closer to home. If we are recommending surgery plus or minus radiation, we will often recommend that they stay at our center given the expertise of our surgical oncology and radiation oncologist. For clinical trials, the patient would have to stay at whatever center has the trial. I understand that it is really helpful for patients to be able to be treated closer to home and not have to do the long travel that can be associated with going to a high-volume sarcoma center, but I believe that having the capability to be seen by a specialist is really important.

Also, involving a multidisciplinary care team is really important for this disease. I work closely with my surgical oncologist, my orthopedic oncologist, and my radiation oncologist to come up with plans that make sense for our patients. All of our disciplines are sarcoma-focused, so it is very helpful for patients to be able to meet with all of us.