Oligometastatic Cancer: An Opportunity for Treatment

Hope

_{Credit:George Frederik Watts (1817-1904). 1855 Public domain}

Oligometastatic cancer. Quite a mouthful, but one that offers solace in the midst of an unwelcome diagnosis. Most of us have used terms to roughly describe the severity of cancer. We've heard about stages...1, 2, 3, 4. Most of us understand that stage 4 means the cancer has spread from the original site to distant sites. It has metastasized. Until recently that's all I understood about the way cancer progresses. Then, sometime last year, a new word was introduced into my world, a special kind of metastasis--oligometastasis.

An article I found in the Journal of the Royal Society of Medicin" explains:

oligometastases is a diagnostic term adopted to frame a therapeutic opportunity.

Focus in that statement on the word opportunity. Most of us, when we hear the term metastatic, think of widespread cancer that requires systemic treatment. We're familiar with Chemo and we've probably heard of biologics. In 1995, two doctors, S. Hellman and RR. Weichselboum coined a term that offered a new diagnostic framing for a subset of cancer patients: oligometastasis. 'Oligo' comes from the Greek word meaning 'few'.

The distinction between a patient with widespread metastatic disease and one with oligometastic disease is that the former likely requires systemic treatment and the latter may avoid that rout, at least for a while. The goal is to avoid systemic treatment for as long as possible because of the side effects such treatment may cause.

Instead of widespread metastatic disease, an oligometastatic patient has localized tumors that appear serially, and may be treated individually. That's what happened last fall to a friend of mine. He was diagnosed with a small tumor on the rib and SBRT treatment was prescribed.

Some of my readers might remember I wrote last year about that friend. He has metastatic renal cancer (doctors' abbreviation, RCC for renal cell carcinoma). At the time, a new cancer, a metastasis of the original cancer, had been discovered on the posterior tenth rib. When I wrote the blog my friend had just received SBRT treatment, stereotactic body radiation therapy, to 'zap' the new tumor.

Page From Medieval Health Book, Taccuino Sanitatis,

_{Credit: "Magister Faragius" (Ferraguth) of Naples. 14th century. Public domain}

My friend tolerated the SBRT treatment well and the treatment seems to have been successful. The rib tumor growth has been arrested.

This friend is described by his oncologist as having oligometastatic cancer.

Effective treatment for a patient with oligometastatic cancer rests on careful monitoring, active surveillance. In my friend's case, that means periodic CT and PET scans. The idea is to catch the tumors when they are small and isolated, while they are amenable to localized treatment.

Last month my friend, the same friend who underwent SBRT treatment, went for one of his routine scan schedules. He had a full body PET scan of his bones and a CT scan of his abdomen, chest and pelvis. The PET scan came up clean, but the CT scan revealed a new lesion, on his right adrenal gland. It is a tiny lesion, 1.9 cm. Discovering a lesion is discouraging, but an isolated tumor that small offers the opportunity for localized, non-invasive treatment.

Odawara--Traveling Uiro Medicine Vendor

_{Credit:Katsushika Hokusai (1760-1849). Public domain}

For this tumor, the oncologist did not recommend SBRT treatment. Instead he suggested microwave ablation. I'd never heard of this procedure. Microwave ablation was first used at Rhode Island Hospital in 1997. Here's a description of the procedure, as I found it on the University of Texas MD Anderson Cancer Center website:

Microwave ablation uses electromagnetic waves to heat and kill small cancerous tumors. These waves are similar to the ones produced by kitchen microwave ovens but are aimed directly at the tumor.

This procedure is considered minimally invasive. It is performed by an interventional radiologist, who uses scans to guide the hand as the tumor is 'cooked'. The doctor inserts a thin needle and hopes to hit the tumor (and nothing else) as tissue is extracted for biopsy, and then the tumor is zapped with microwave energy.

It's obviously important to have a highly skilled interventional radiologist to do this. In some studies microwave ablation has a 93% effective rate for this sort of tumor. The smaller the tumor, the more likely the success. This is very good news for my friend.

Different cancers respond differently to the treatment. Fortunately, microwave ablation has demonstrated excellent efficacy in locally treating RCC tumors that have metastasized to the adrenal gland. An article that appeared in the International Journal of Hyperthermia compared microwave ablation to surgical removal of a tumor. The long-term (3 year and 5 year) success rates were higher for ablation. Also, complications from surgery, including hospital stays, were greater with surgery than with ablation.

The other day, I went with my friend for a consult with the interventional radiologist who would be performing the procedure. He was highly recommended by the oncologist and also is highly rated by third-party reporting sources. While we went with a number of questions, he quickly silenced us. He explained exactly what the procedure involved. When he was finished talking, he had answered all our questions and had addressed some we hadn't considered.

One thing he suggested was that instead of zapping the tumor with microwave heat, he might freeze it. This is called cryoablation. He said he might choose to do cryo once he has begun the procedure.

Medicine Man

_{Charles Marion Russell (1864-1926). 1916.Public domain}

When we left he gave my friend 'homework'. One assignment was to get a blood test that would screen hormone levels. This would indicate if there might be issues with the adrenal gland before the procedure was attempted. There is the assumption that this is an RCC metastasis, but it could also be a primary adrenal tumor (small chance). Hormone irregularities would suggest the latter case.

Also during the surgery precise monitoring of blood pressure would be essential. This would indicate if there was any difficulty with the adrenal gland during the procedure. In that case, immediate treatment of the issue would be essential.

When we left the doctor's office we felt confident, much more confident than we had felt when we went in. This doctor had anticipated every question and was taking every precaution to prevent complications during and after the procedure.

Conclusion:
I've learned a lot about cancer treatment in the last few years by accompanying my friend during this medical challenge. Treatment for cancer is evolving rapidly. It seems everyone needs to be evaluated individually. The course of treatment and outcome, it seems, are greatly influenced by the oncologist who guides the treatment plan.

I have been surprised by so much that has occurred in the last few years. I don't think anyone expects a cancer diagnosis, but we all know that either we or someone we love will likely be challenged by this disease. I think that if we understand how a doctor frames the disease, how the doctor plans to go forward with treatment, we can better sense of control over our lives.

There is no single path forward in cancer treatment. Different doctors make different treatment decisions. The course we ultimately follow is determined by us, the patients. We need to understand the disease and the treatment options to make decisions.

Thank you for reading my blog. Health and peace to all--Hive on!