Damage Control

The prescribed systemic therapies (targeted therapy, chemotherapy, immunotherapy, and/or hormone therapy) that bone metastasis patients are already taking to treat their primary cancer may or may not stall growth in the bone.

Most patients with bone metastasis, Brigman said, are treated intravenously with drugs, such as denosumab, zoledronic acid, or pamidronate to reduce pain and damage to bone, lower the risk of breaks, and reduce high blood calcium levels.

Bone metastasis patients may also benefit from radiation therapy (high-energy x-rays) and or radiopharmaceuticals (drugs with radioactive elements) — both of which kill or slow the growth of cancer cells and relieve pain.

A complimentary option, explained Sag, is image-guided bone tumor ablation, whereby cold (cryoablation) or heat (energy) is deposited into the tumor using special probes through 3 mm incisions. If desired, a biopsy of the bone tumor can be obtained through the same access incision at the same session. These are typically outpatient procedures.

Also, at the same session, the bone can be strengthened or stabilized by injecting bone cement or glue (also called cement augmentation, cementoplasty, or in the spine, kyphoplasty), if needed. If cryoablation is performed, it can also freeze the painful nerves in the vicinity of tumors, allowing extended durations of pain relief up to six months, at which point the cryoablation can be repeated. These modalities are safe in areas that have been previously treated with surgery and radiation.

Interventional radiology, said Sag, can also help enable some surgical options. A procedure called embolization, when performed the day before surgery, can reduce tumor bleeding during surgery and speed the intra-operative course. (This is a process through which the blood vessels to the bone tumor are accessed using a microcatheter — approximately 1 mm in diameter — and particles are delivered to block the blood supply to the bone tumor.)

Kidney cancer and lung cancer that’s metastasized to the bone — typically more aggressive tumors — are more likely than breast or prostate cancer patients to need and benefit from surgery.

“We do operate on people with breast cancer or prostate cancer, but the percentage of those patients that need surgery is much lower,” said Brigman.

A common way for an orthopedic surgeon to treat patients (not cure the cancer) has been to use a metal rod (intermedullary nailing) to strengthen the bone, prevent fracture, and reduce pain, he said, but there’s an increasing number of these patients “outliving their reconstruction.”

“As these patients live longer, the disease will continue to grow and destroy much larger parts of the bone and make it such that the reconstruction fails and they need another surgery,” explained Brigman, who published on this, with Eward, about a year ago. “This problem is only going to get worse.”

There’s a higher likelihood now, he said — in cases of kidney cancer that’s spread to the bone, for example — that Duke surgeons will resect the tumor and reconstruct the bone with a prosthesis rather than stabilize it with a rod.

“Resection, of course, is a much bigger operation,” said Brigman. “If the patient were to die of that disease within a few years, we wouldn’t put them through such a big operation. But now, if the patient is expected to live a lot longer, it’s worth considering these interventions even if the recovery path is more difficult than with less invasive procedures.”

Frozen in Time

Pam Kohl, for one, has already benefited from the collaborative efforts of an array of specialists in the bone metastasis space.

In late 2018, after the tumor in her left hip was diagnosed, her care team decided the best course was SBRT (stereotactic ablative radiotherapy), which trains several precisely focused radiation beams on the tumor. Her cancer was stable for another year.

When, this past December 2019, a tumor in her lower mammary lymph node appeared, SBRT was called for again.

A new strategy was considered when, in January 2020, a second tumor emerged in her left hip — making it Kohl’s fifth tumor over the span of three years and the second one to the bone. This time Kohl’s core care team brought Sag into the conversation. Kohl’s tumor (small at 1cm), he explained, was the perfect size for cryoablation.

Guided by CT, he’d make a 3mm incision through the skin into the bone, drilling straight into the tumor where he’d extract bits of the tumor for biopsy to see if Kohl’s cancer had mutated yet, and if so, if there was a drug available to target that mutation (either approved or in clinical trials).

Then, still guided by CT, he’d insert a probe, which, once inside the tumor, would make just the right size and right temperature ice ball (-40 °C ) that would, within seconds, shatter the tumor cells and tear apart the tumor DNA. The body would clean up what was left of the debris. The whole session would take about an hour-and-a-half.

“Cryoablation technology has gotten smaller, safer and gentler on patients,” said Sag, who specializes in treating bone and spine metastasis. “The big wins with cryo are you can do it while the patient’s awake, you don’t have to stop chemotherapy, and you can get a biopsy at the same session. It can also be combined with surgery and radiation. It doesn’t delay any other treatment and it can be repeated. If something comes back or if there’s another tumor adjacent, you can always go back and refreeze.”

Kohl was intrigued by this “new” option more commonly used to treat kidney, lung, and liver lesions, but increasingly, she learned, a technology that was also being deployed in the bone.

Over the past couple years, she’s openly shared her cancer journey with DCI, WRAL-TV’s Debra Morgan, and the local breast cancer community. She even agreed to having her cryoablation and biopsy procedure filmed for TV. WATCH: Pam's Story: Treating Tumors with Ice to Buy Time

She was awake and talking the whole time. Afterwards, she felt bruised, but required no painkillers and felt no nausea or fatigue. She even stayed up late that night to watch the Carolina game.

“When I was first diagnosed three years ago, I was told no surgery, no radiation, none of that kind of thing with metastatic breast cancer unless it’s palliative, to relieve pain,” said Kohl. “But it’s three years later and I am doing really well on my first line of therapy. My tumor markers are low and overall I feel pretty well. A lot of us are living longer and well on systemic therapies. Rethinking “metastatic,” being aggressive with it, doesn’t mean that we’re curing it. I’m going to get additional tumors. But these kinds of interventions, early on in stage 4, may help prolong my life. We don’t have the data, but I’m so thrilled, just grateful that I am fortunate enough to be in the Triangle where there’s the best care available to folks and where I can be a partner in deciding how to proceed and be part of the data.”

In January, Kohl transitioned from leading the N.C. Triangle to the Coast Affiliate of the Susan G. Komen Foundation to leading the charge for a new affiliate initiative — her brainchild — designed to fast-track collaborative bench-to-bedside research in MBC by Duke and University of North Carolina at Chapel Hill researchers.

For Kohl, and thousands like her, the answers can’t come soon enough.