Oligometastatic cancer: What patients with stage IV cancer should know

What does it mean when your cancer has spread? Many patients given a cancer diagnosis of metastatic cancer or stage IV cancer do not know to ask if they qualify for oligometastatic treatments.

Oligometastatic cancers occur when cells from the original tumor travel within the body to one or a few sites forming new tumors. Oligometastatic disease is most common in kidney, lung, prostate and colorectal cancers.

We spoke with radiation oncologist Chad Tang, M.D., who specializes in the care of patients with oligometastatic cancer, to learn more. 

What is oligometastatic cancer? 

Oligometastatic cancer describes an intermediate stage of cancer between localized and widely spread disease. We classify oligometastatic as a subclass of stage IV cancer. If you have oligometastatic cancer, that means cancer has spread to fewer than five sites in your body.

Historically, radiation therapy was not routinely used to treat stage IV cancers, except to manage symptoms. Instead, patients received drug therapy. This is because while local therapies only target a specific part of the body, drug therapies target the entire body. 

We can now see the sites of metastatic cancer with every improving diagnostic imaging. This allows us to target these sites with radiation therapy to delay the spread of metastatic disease for certain cancers.

How are oligometastatic cancers treated? 

When cancer has spread, targeted therapy and immunotherapy may be effective. Like chemotherapy, targeted therapy drugs can stop or slow the spread of cancer on a cellular level, including sites of disease we can and cannot see.

Once we determine how many spots of the disease patients with stage IV cancer have, we’re able to determine if the cancer is oligometastatic. Based on that information, we may be able to identify additional treatment options.

What are the most common types of oligometastatic cancers, and how are they treated?

Each of the four common types of oligometastatic cancers is treated a little differently:

• Oligometastatic prostate cancer is treated with systemic therapies, like radiation therapy or hormone therapy. Using radiation therapy gives patients a much longer break from hormone therapy. This can improve quality of life with reduced side effects and decrease cardiovascular risks. If patients experience elevated prostate-specific antigen (PSA) levels, they can start back on hormone therapy.  
  
  
• Oligometastatic non-small cell lung cancer patients often see long-term benefits from using radiation therapy or surgery after some immunotherapy or chemotherapy. 
  
  
• Oligometastatic kidney cancer can be treated with stereotactic body radiation (SBRT) and other forms of radiation. It provides a good option for stopping further spread of disease in oligometastatic  kidney cancer patients and may allow for prolonged breaks from drug therapy.
  
  
• Oligometastatic colorectal cancer occurs when colorectal cancer spreads to other sites in the body. The first site is often the liver. When oligometastatic colorectal cancer is limited to the liver, it’s treated most effectively with SBRT, radiofrequency ablation and surgery.

What clinical trials are available for oligometastatic cancers?

As a leader in treating oligometastatic cancers, MD Anderson has clinical trials for patients who have newly diagnosed, recurrent or progressive diseases. 

A recent oligometastatic prostate cancer randomized Phase II study called the EXTernal Beam Radiation to Eliminate Nominal Metastatic Disease (EXTEND) shows metastasis-directed radiation therapy improves progression-free survival and allows for time off hormone therapy. This study provides much-needed data on the benefits of combining these newer radiation techniques with hormone therapy to improve outcomes. EXTEND is also testing metastasis-directed radiotherapy for pancreatic, breast, kidney and other cancers.

A recent oligometastatic kidney cancer clinical trial called the MD Anderson RCC Oligometastasis Phase II trial investigated receiving stereotactic body radiation (SBRT) to delay systemic therapy for oligometastatic renal cell carcinoma (RCC). In this study, investigators offer patients additional courses of radiation therapy if one to three sites of metastatic disease appeared. The strategy of repeated radiation was associated with minimum side effects.

These clinical trials focus on keeping options open for patients with oligometastatic genitourinary cancers by using  radiation therapy  in an attempt to delay the need for drug therapy. By using radiation therapy first, we can buy our patients some high-quality time. I tell my patients we are taking the drug therapy and putting it in their back pockets to be used when necessary. 

What advice do you have for patients with a new oligometastatic cancer diagnosis?

Treating oligometastatic cancers accurately requires a multidisciplinary team. Finding the right care team will connect you with the latest clinical trials, the most innovative ways of identifying disease and delivering local therapy and new targeted therapies. 

If your doctor says the cancer is stage IV, ask if it is oligometastatic. If you have a limited number of spots, up to five, ask about local treatment options, such as radiation therapy. 

If you are experiencing challenging side effects, talk to your care team. We can help you come up with strategies to cope. Our goal is to turn a terminal diagnosis into a chronic disease.

Request an appointment at MD Anderson online or by calling 1-877-632-6789.