Metastatic lung cancer has several options for treatment, but ablation should the first choice therapy, according to an RSNA 2016 presentation delivered by Chief of Interventional Radiology Stephen B. Solomon, MD, of Memorial-Sloan Kettering Cancer Center.
Cancers were historically treated as either local or widespread, until the introduction of the spectrum theory of disease by the University of Chicago’s Samuel Hellman in 1994. Hellman posited that metastases are a function of tumor growth and progression, instead of a binary indication that the cancer is of a widespread variety.
This category of disease is called oligometastatic disease.
“There’s several steps that make a cell go off and spread. In this concept, tumor cells lacking the genetic requirements for metastases may slough off and travel throughout the blood, but until they have the certain mutations required to settle down, there’s this intermediate step,” said Solomon. “That’s what we’re targeting.”
Studies have shown the benefits of treating these metastases with radiation or surgery, but Solomon believes that ablation outstrips other modalities in value and patient experience—especially when selecting the right patients.
Qualifiers such as good performance status, solitary limited disease and single or limited organ involvement are all indicators that ablation of metastases could benefit the patient. However, Solomon cautioned session attendees to be mindful of patient bias inflating the success of ablating metastatic disease.
“That bias can come from choosing the most favorable patients to undergo these treatments, or with longer disease lead times,” said Solomon.
Even with the potential for bias in mind, ablation has shown to be the most effective treatment for lung metastases. Ablation’s precision makes it a superb tool for limiting collateral damage and maintaining lung function, especially for lesions deep in the lung that are difficult to access surgically. Pulmonary function tests after ablation show relatively no change, according to patient studies. In addition, assessing the outcome of the procedure is much easier than if the patient had undergone chemotherapy.
“When we look at patients after radiation treatment, it’s very hard to know whether it was successful or not because of the inflammatory response afterwards,” said Solomon. “It’s oftentimes easier to make that distinction with ablation, where you see [via contrast] that the pre-ablation activity has lessened.”
Increased patient quality of life is another advantage of ablation. After a successful lung ablation, oncologists elected to stop radiation therapy for over half of patients, giving them a “chemotherapy holiday."
All methods of ablation preformed similarly when treating lung metastases, so Solomon encourages using the modality practices are most comfortable with.
“Cost, patient toxicity and the number of visits are all lower with ablation,” said Solomon. “When you think about it, the case for ablation is made with a single visit, potentially repeatable if other metastases occur, preservation of lung function, and the patient quality of life."