Does Surgery for Solitary BCa Bone Mets Tumor Prolong Survival?

“De novo” Stage IV breast cancer diagnosis

Roughly 6-10% of women initially diagnosed with breast cancer (BCa) are found to have Stage IV disease. This means that the cancer has already spread to distant sites, e.g. bone or liver. This is called de novo Stage IV breast cancer. “De novo,” a Latin term, literally means “of new” but in medicine it means “from the beginning.” In other words, BCa had already spread at the beginning of the diagnosis.

Stage IV BCa is not curable, so diagnosis can be extremely disheartening. However, patients should not give in to fear and despair. There are now treatments to control metastatic BCa both locally (at the site of new lesions) and systemically through chemotherapy and immunotherapy. This means living longer with better quality of life unavailable to previous generations of women.

Oligometastatic BCa

Some women with de novo Stage IV BCa will have only a single or very few detectable metastatic lesions. This is called oligometastatic (OM-BCa), and means that such patients have less “disease burden.” There is no universal treatment strategy for OM patients because of individual patient factors: the type of BCa (e.g. estrogen receptive vs. non-estrogen receptive), age and general health, immune system strength, location of remote lesion, etc. Therefore, on an individual basis, some OM patients may be considered candidates to have the lesion(s) surgically removed from soft tissue organs like the liver.

Surgical removal has advantages and disadvantages. Data from many studies suggests that taking out the largest metastatic tumor extends life expectancy, an obvious advantage. However, there is evidence that surgery itself increases the risk of recurrence, including more aggressive disease. Why would this happen? Well, surgery is a wound, and the body increases its production and circulation of growth factors to speed healing; at the same time, existing microscopic tumors can take advantage of those growth factors. Another consideration is that anesthesia may suppress the immune system, making it less able to destroy cancer cells that are traveling in the blood and lymphatic fluid. The good news is that improvements in minimally invasive surgery and anesthesia reduce such risks, but to an unknown degree.¹ Again, one patient may have better results than another due to individual differences.

Surgery for oligometastatic BCa to the bone (BCa bone mets)

Some researchers are asking if a patient with a solitary bone lesion (bone mets) can benefit from surgically removing it. The findings are mixed. Two papers were presented at the 2016 meeting of the American Society of Clinical Oncology (ASCO) on this approach. Dr. Atilla Soran presented the results of a study comparing patients who had systemic therapy along (chemotherapy) vs. those who had systemic therapy plus surgery. Some of the 274 women in the study had mets in more than one location including a solitary bone lesion, and some OM patients had a single bone-only metastasis. Overall, Dr. Soran noted: “In the first 3 years, we found that survival was similar for surgery and no surgery, but longer follow-up revealed a significant improvement of about 9 months in median overall survival. Five-year overall survival was 42% with surgery, vs 25% with systemic therapy alone.”² Data analysis broke it down further: “Surgery added an additional … 10 months for patients with a solitary bone metastasis [but lesions in other organs as well], and 14 months for patients with bone-only metastases…”³

On the other hand, a study presented by Dr. Tari King found no differences between groups in a study of 112 patients, divided into the same arms as the Soran study.

Local treatment for bone mets

More research is needed, but Dr. Soran’s experience gives hope that treating a solitary BCa bone mets lesion is worthwhile, especially for OM BCa patients with a single bone-only lesion. However, identifying truly OM patients can be challenging, but today’s imaging, especially multiparametric MRI (mpMRI) and PET-CT scans, are better than ever at picking up even very small tumors in bone and soft tissue.

According to DiLascio & Pagani, at BCa diagnosis “5–6% of patients present with distant spread, bone being the most common metastatic site. Bone is also the first site of distant relapse in > 50% of patients, and bone-only metastases occur in 17–37% of patients with distant relapses.”⁴ The authors cite authoritative studies in which local treatment of a solitary bone-only metastatic lesion produces median survival rates of 65 months. At the time of publication (2014) the authors suggest that noninvasive radiotherapy for such lesions is the treatment of choice, specifically stereotactic body radiation therapy (SBRT) which can be more precisely focused to avoid collateral damage and deliver optimum doses.

MR-guided Focused Ultrasound (MRgFUS) for bone mets

Within a few years of the DiLascio article, the treatment of bone mets using noninvasive MRgFUS is changing the standard of care. Like radiation, MRgFUS is noninvasive – but all similarity ends there. MRgFUS uses ultrasound energy to create sufficient heat to ablate (destroy) a bone lesion at the time of treatment. The outpatient procedure uses no surgery or radiation exposure. Thanks to the high resolution imaging of MRI, the planning, delivery, monitoring and confirmation of effectiveness are done in a single treatment session. There’s no waiting for weeks to find out how well the treatment worked.

It stands to reason that MRgFUS is a desirable alternative to surgery and radiation, while providing the same survival benefits. For properly chosen patients, DiLascio & Pagani suggest that local treatment of BCa bone mets may even have curative value. The Sperling Medical Group offers MRgFUS for the relief of pain and debulking of tumor burden in cases of metastatic bone disease. To learn more about MRgFUS as a treatment for metastatic cancer to the bone, visit our website or contact us for a consultation.

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¹ Di Lascio S, Pagani O. Oligometastatic breast cancer: a shift from palliative to potentially curative treatment? Breast cancer (Basel). 2014 Feb;9(1):7-14.
²Helwick, Caroline. “Mixed Results with Resection of Primary Tumor in Stage IV Breast Cancer.” ASCO Post, July 10, 2016. http://www.ascopost.com/issues/july-10-2016/mixed-results-with-resection-of-primary-tumor-in-stage-iv-breast-cancer/
³Ibid.
⁴Di Lascio, Ibid.