Which patients should we and should we not be operating on?
One of the things that that has gone on in the field of spinal metastasis has been an evolution towards more surgery. In the eighties and nineties there really was a movement against operating on folks who had spinal metastases. And then there was a study by Patchell, a prospective randomized study, that shed some light that perhaps surgery, or operating on patients, in some cases, can actually be much more beneficial than not operating. And with that study, that really led to multiple, or a large increase in patients being operated upon.
So, what’s happened over the past several years has been trying to figure out which patients should be operated on. At one point we weren’t operating on very many, and then we started operating on a lot of them. And the question is, “Which ones should we and which ones should we not be operating on?”
For instance, two factors that one must take into account when considering surgery.
How long are patients expected to survive? Predicting survival has been an area of great research interest by multiple different institutions and individuals. The idea is that you want to be able to determine how long someone likely will survive, in order to determine if they would benefit from an operation. If someone’s going to live just for a week or two, or a few weeks, it may not make sense for them to go through a morbid operation. Whereas if somebody is expected to live for well over a year, and if you’re going to operate on them, you want to give them an operation that is durable. So being able to predict survival has been a great area of research. There have been a lot of publications in this arena, including the use of machine learning.
Another area that is being studied quite a bit is trying to predict fractures – whether or not someone has instability or is likely to develop a fracture because of a bone lesion in their spine. And there was really a change in the field with the publication of the SINS (Spinal Instability Neoplastic Score) criteria. That scoring system helps in establishing which patients are stable and which patients are unstable.
But even with that study, there is an intermediate group where it may or may not be stable. That has left a window open for many other researchers trying to parse out, in that intermediate range, who is truly unstable. There have been several studies looking into this, trying to use different radiologic parameters to predict fractures. That is an area of research that’s in evolution, as opposed to the survival prediction models which are a little more mature.
Considering Patient Population
There are differences, of course, amongst patients. The population of patients that get cancer is perhaps a little bit younger, but there certainly is crossover of patients who have osteoporosis. Osteoporosis can happen in men and women, but it’s more common in women. So if you have a woman who has osteoporosis, and then in addition to that, they have metastatic bone disease, that would likely increase their chances of fracture. One of the parameters that is being looked at very closely is that of osteoporosis. What is the state of patients’ bone before they develop metastasis?
Other factors that are important, for instance, if someone has a lytic lesion– a lesion that is really eroding bone completely. You end up having an area in the spine where there’s just nothing there. No bone at all, just tumor. Those patients are at probably higher risk of developing a fracture than those patients who have a mixed picture, or a blastic lesion, where the actual mineralization of the bone is actually increased.
Taking a Multidisciplinary Approach
Most centers that treat a lot of patients with bone metastasis, or in our case at Mass General, we have a bone metastasis clinic. I am also part of a sarcoma clinic. In both cases, it’s a multidisciplinary approach. These multidisciplinary approaches usually have a shared conference, and they also often have shared clinic space. What that means is, a patient will come in and they’ll be seen, by not just a surgeon, but they’ll be seen by a medical oncologist, or a radiation oncologist, and their images and their case will be presented amongst the treating physicians, but also amongst pathologists and radiologists. So you truly get a multidisciplinary approach to care.