I’ve discussed the general management of metastatic lung cancer, both SCLC and NSCLC, but there are also several common complications that sometimes require particular management. Bone metastases, for instance, may be treated by the same “whole body” approach with chemotherapy that treats other areas of tumor involvement, but may also benefit from additional approaches. Bone metastases are common in oncology, and approximately 30-40% of lung cancer patients develop bone metastases at some point, about half presenting with evidence of bone involvement at the time of diagnosis (bone metastases general review abstract here). These metastases often have a significant impact on a patient’s quality of life, leading not only to pain but also a risk for pathologic fractures (bone breaks because the bone is weakened by cancer involvement leading to reduced structural integrity), potential compression of the spinal cord and other nerves, and high blood calcium levels as bone is broken down (which can lead to confusion, constipation, numbness/tingling, and other problems). With bone metastases comes a risk of impaired mobility, problems with sleeping and eating normally, and a somewhat worse prognosis overall, although there’s a lot of variability in the population.
Treating the underlying cancer with chemotherapy and/or targeted therapy (systemic, or “whole body”) can also lead to improvement in disease in the bones, but sometimes local therapy is indicated. The goals of treating bone disease are primarily to relieve pain and to reduce the risk of fracture, which tends to occur in “weight-bearing” bones like the legs, hips, and spine.
Of the patients with lung cancer who ultimately develop bone metastases (somewhere in the range of 50% of patients with advanced disease), the metastases are without symptoms in 30-60% initially, which leads to this being an underdiagnosed and undertreated problem. The majority of these are in the spine (thoracic or lumbar vertebrae, mainly), ribs, and pelvis; and less likely but sometimes seen the cervical spine (in the neck), femurs (thighs), humerus (upper arm), scapula (shoulder blade), skull, sternum. It’s fair to say that they can be anywhere in the spine, but more likely in the torso, and in the extremities more likely to be higher up.
The most common way to detect bone metastases used to be bone scans, but they used less and less now as PET scans have become more widely available. Bone scans are falsely positive (light up as abnormal but not really cancer) in the setting of prior trauma or degenerative joint disease, and many people have one or more of those, so it can be very difficult or impossible to tell if the spine abnormality on the bone scan is metastatic disease or just garden variety disk disease, the kind that makes back pain one of the top reasons for people to see a health care professional. PET scans are more sensitive (able to pick up disease better) and more specific (what they pick up is more likely to really be cancer) (one abstract on PET for bone mets here), and they’ve become much more widely available. However, many if not most PET scans stop at the mid-femur level, so it’s possible to miss disease lower down in the legs – an uncommon but certainly possible place to develop bony metastases.
Often, those scans still can’t definitely proclaim an abnormal area as cancer. MRI scans are often very, very good at determining details of bony disease and clarifying whether an abnormality is cancer or degenerative changes. Some people can’t undergo an MRI scan because they’re loud and pretty tight, leading about 10% of people just unable to tolerate the close confines. CT scans with “bone windows”, just a way of setting the contrast on the scans, can be useful to assess the bones in people who can’t get an MRI. And then there’s also plain old x-rays, which are also potentially useful in assessing the hips or ribs or other places. They aren’t as clear as an MRI, but they can sometimes provide the added information you need and are certainly widely available and a lot less expensive.
Even with additional studies, sometimes it’s not possible to say definitively whether abnormal areas on these scans are cancer or benign musculoskeletal disease. Occasionally, we need to recommend that patients undergo a biopsy to confirm or exclude bone metastasis. That wouldn’t be widely recommended in most situations in which a patient already has advanced lung cancer, since it’s not as likely to dramatically change treatment plans or prognosis, but in patients who are being staged and may be candidates for surgery and/or aggressive chemo/radiation plans for earlier stage disease, it often makes sense to pursue such a challenging approach only if it wouldn’t be proved futile by progression of metastatic disease in the forseeable future.
I’ll talk about various treatment approaches for bone metastases in some upcoming posts.
posted by Dr. West @ 4:50 pm link to this post
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June 4th, 2008 at 7:24 pm
Maruchi,
I don’t have a definitive answer, as I’m not there and don’t know her as well as her doctor. But if I have a patient so tired and weak that they aren’t really walking, I usually favor focusing on just having a patient feel as good as they can, rather than adding more chemo that make a person feel worse rather than better.
Her oncologist certainly knows more than I do about her current situation, but sometimes doctors just want their patients to continue to do well and have a hard time not trying one treatment after another.
Good luck. I hope she feels better.
-Dr. West
June 3rd, 2008 at 7:35 pm
Dr. West: Mari has pain in her knees and a lot of numbness in her feet. The doctor says it might be neuropathy form the chemo for her bone metastasis. He even suggests an orthopedist for her knees. She is now in bed and can barely walk. Her sodium is kept at a decent level with demeclocyclin and gets dehydrated easily. However he says he will change her chemo to buy her time and give her quality of life. Is he beeing over optimistic? Should we let her rest? How do you know when the end has come? Thanks so much for your March reply and God Bless you for all the help you give us.
Best to you always,
Maruchi
March 30th, 2008 at 10:41 am
Ellen,
I don’t think we know nearly enough about why mets settle in one place and not another. Perhaps there is something about the microenvironment around the site of prior injury that leads to a stronger blood supply or more “adhesion molecules” that make the area stickier to passing cancer cells. It does seem to be the case that we often find areas of micrometastatic deposits in places that don’t grow to become visible, clinically important metastases, so there are likely several variables that contribute to why one micrometastatic outpost thrives and 4 others just stay microscropic or die — sort of the way some startup companies or early town settlements become big while others fade away. There are likely many factors, and we’re still a ways away from understanding.
-Dr. West
March 30th, 2008 at 10:31 am
Hi Dr. West and everyone else.
Just a comment about the claim that bone mets often occur at the site of a previous injury or surgery — my ONE bone met is precisely at the site (on the iliac crest) where they harvested bone for a bone graft for a spinal fusion 8 years ago. The oncs also never heard of such a site ‘attracting’ a metastasis and I found it such an extreme coincidence that I demanded a biopsy — and it was in fact a met. So maybe there is something to that claim…
March 23rd, 2008 at 1:15 pm
Maruchi,
Some patients have little or no pain from bone metastases, and others have more pain, but there are no rules about what happens. The most important factor, though, is that oncologists and other doctors have a wide range of pain medicines available to treat and manage pain effectively. Most patients can be kept pretty comfortably and without significant pain control issues if the doctor and patient aren’t shy about treating the pain adequately, which often requires a steady escalation of narcotics, and bowel medications with that, to be adjusted to keep pain controlled.
I an not an expert in alternative medicines, and I have significant biases against it. My perception is that a distressing proportion of alternative medicine practitioners make very optimistic claims based on a case or two, when we all have cases that defy the odds. The case this pharmacist described may have had an astounding result and beaten the odds, but if this long survivor actually has bone metastases from prostate cancer, a five year survival is not unusual at all, and perhaps the thing that made him seem miraculous is that the other doctor was way off base predicting six months. When I look at alternative medicine marketing pieces, the vast majority hype a case of someone who defied the odds. Every week I see a few people who defy the odds, but I don’t claim that it was because I laid hands on them. My personal opinion is that a lot of the alternative medicine industry capitalizes on the desperate need for hope to trump rational assessment of a situation. When you want to believe something enough, you won’t allow yourself to be skeptical, and all it takes is a lottery winner to make you expect that you will also win the lottery. But they don’t highlight that their odds of winning are also 1 in 100 or 1000 or worse.
I wish the role of educating about what to expect from cancer, and lung cancer in particular, didn’t include such a sober view of what to expect (although there is still room for hope, and when I am positive, I really mean it). It’s easier and probably more profitable to withhold information and be unrealistically optimistic. But I feel that people deserve the truth and not a sugar-coated version.
-Dr. West
March 23rd, 2008 at 3:32 am
Dr. West: Hello again. Mari just had a Pet Scan which reveals bone metastasis. The doctor gives her 8-12 months and says she will have quality of life and no pain. How is this possible? Is there different types of bone cancer with no pain? Should she continue treatment or stop? Also, I met with a pharmacist who is into alternative medicine (Chinese herbs, roots, etc.) who says her brother had 6 months and has live 5 years with bone cancer. Is this possible? We are really desperate.
Thanks again in advance.
Maruchi