At the Society of Interventional Oncology (SIO) annual scientific meeting (19–23 January, Washington DC, USA), Sean Tutton (University of California San Diego Health, San Diego, USA) presented evidence on treatment for musculoskeletal (MSK) metastases, while urging those involved in these patients’ care, as well as collecting data on their experiences, to “harmonise the nomenclature” they use to optimise data and care quality.
Tutton began by suggesting that a reason for inconsistent terminology where bone cancer treatment is concerned, among interventional radiologists, is that it is a “young” part of the interventional radiology (IR) space. “We need to start talking about skeletal-related events—both the cancer as well as the cancer therapies are having a significant impact on the skeleton,” he urged. An example of why this issue is relevant for interventional radiologists, which Tutton gave, was that of a post-menopausal patient who, after chemotherapy, underwent “an 8% year-on-year bone loss”. This increases the risk of fracture, the speaker underlined.
Moving on to focus on pelvic metastases specifically, the presenter noted that they are the second most common type of skeletal metastasis after spinal. In Tutton’s view, it is crucial to understand that patients with cancer metastatic to the pelvis may experience different types of pain—mechanical pain is not the same as bone-tumour interface pain, which, in turn, is not the same as neuropathic pain. “We address them differently,” Tutton emphasised.
Likewise, there are different classifications of disease stage depending on the type of skeletal metastasis. In the pelvis, the Harrington scale runs from one to four, with complete pelvic discontinuity at the end of the gradation, Tutton informed delegates. Treatment for these metastases differs based on the classification—Harrington 1 is “ablation alone”, 2 is a combination of ablation and osteoplasty, and for profound Harrington 3 and 4, the preferred treatment modality is “osteosynthesis, which is a combination of cement and screws,” the presenter outlined.
Tutton proceeded to run through the biomechanics behind using cement and screws, stating that he and IR and orthopaedic colleagues had seen in their experience that using screws alone is “very similar to not treating at all”. While “cement alone only deals with compressive forces”—and the pelvis also has to be able to deal with “bending, sharing and tortional forces,” Tutton detailed—cement and screws work in conjunction with one another to “shift the load-bearing away from the bad bone to the good bone”. He supplemented this by saying that “the key concept is that you are fixing bicortically if possible”. With the two materials combined, you achieve “the highest stiffness and greatest yield strength”. A further point Tutton made was regarding working with orthopaedic colleagues and how there, uniform nomenclature is key.
The speaker was keen to highlight that the cement plus screw combination is for progressive disease, with Nick Kurup and Matt Callstrom having reported on their experience with Harrington 1 and 2 lesions. Tutton labelled their use of balloon-assist osteoplasty and ablation as a “very novel way of dealing with periacetabular lesions”.
Regarding the body of data that exists within IR for treating skeletal metastases, Tutton acknowledged that there are “a lot of great retrospective data,” which help interventional radiologists build their “toolbox” and stipulate how to use cone beam computed tomography (CT), how to plot navigation lines and how to improve accuracy.
Speaking on his and colleagues’ experience, Tutton averred that the aforementioned pelvic procedures are “safe”, with no significant blood loss or infection reported. Following treatment, the patients he studied saw an improvement in terms of function and narcotic use. At one-year follow-up, the presenter shared that they were able to obtain “good data” on 42 of 105 participants—“we are in the process of reporting,” Tutton told attendees.
“The value” of studies like his is that “as we treat these patients and they survive, which is great […] 43% will need some form of additional procedure—you are going to need to see these folks [again],” was one of Tutton’s main messages for the audience. In order to add to their value, he opined that there needs to be, again, “harmonisation” of the outcome metrics, patient-reported and otherwise, “so that when we publish we all speak the same language”.
In conclusion, Tutton expressed how patients living longer with pelvic metastases is a “huge win”, but that in order to give them the best possible quality of life, it is necessary to continue along “the right track” that IR is on with evidence surrounding osteosynthesis. “Skeletal metastases are common and devastating for quality of life,” so harmonised evidence reporting and use of nomenclature will contribute to “[allowing patients] to continue their cancer therapies and to get walking and actually enjoying life”.
