Genetic Testing Again Proves Important for Pheochromocytoma Treatment

Pheochromocytoma and Paraganglioma

Pheochromocytoma refers to a type of tumor that arises from chromaffin cells. They normally occur in the adrenal medulla. However, 10% of these tumors occur outside of this area, instead forming in the neck, bladder, heart, or chest. Tumors in these locations are referred to as extra-adrenal or paragangliomas.

Pheochromcytomas are present in less than 1% of people diagnosed with high blood pressure and many live their entire life undiagnosed. These tumors are normally not cancerous and some people never even experience symptoms. However others deal with heart palpitations, headaches, excessive sweating, dizziness, paleness, fatigue, and hypertension.

Treatment options include removing the tumors via surgery, medications which help to stabilize blood pressure, and genetic counseling. However, although genetic testing has been shown to be extremely beneficial for patients, many still do not receive it. Why is this? The answer is not very clear.

Recent Findings

A recent retrospective study has reinforced the fact that genetic testing is important for pheochromocytoma patients.

It’s important to note that genetic testing soon after diagnosis is a part of the guidelines that are endorsed by the Endocrine Society as well as the European Society of Endocrinology. Therefore, this study only reinforces what has already been determined as the recommended standard of care. Unfortunately, this study also clearly indicates that the guidelines have not been followed as closely as some might have thought. It is clear that better care needs to be given to pheochromocytoma patients. Hopefully, this study will provide additional insight to physicians on the importance of genetic testing as part of the standard care given to this patient population.

Additionally, this study clearly indicates the benefit of frequent surveillance of the clinical outcomes of patients who have a genetic predisposition.

Results from this recent study were published in The Journal of Clinical Endocrinology & Metabolism.

Retrospective Study

A retrospective study included 221 individuals living with a pheochromocytoma or paraganglioma diagnosis. All participants had a germline mutation in SDHD, SDHB, SDHC, or VHL. The data from these patients came from 24 centers in France. 125 of the participants had received genetic testing within 1 year of being diagnosed. These patients were referred to as the genetic group. The remaining 96 patients were given a genetic test 7 or more years after diagnosis. This group was referred to as the historical group.

This study showed overwhelmingly positive outcomes for the genetic group versus the historical group. The genetic group experienced an overall less severe course of the disease, smaller new metastases, and lower metastatic spread. The patients in this group who developed metachronous metastases also had improved 5 year survival. These results were all in stark contrast to the historical group. What is truly telling though is that all of the negative experiences documented in the historical group were reversed after patients in that group received genetic testing. Additionally important to note is that patients in the genetic group had more examinations than the historical group. In fact, 54% of those in the historical group received no follow-up at all until 7 years after they had been diagnosed. 

This study clearly shows that not only is genetic testing beneficial for patients with paraganglioma and pheochromocytoma, it can literally change the course of their disease and their entire patient experience. Once they receive the proper testing they can be referred to the proper specialist who can provide them the individualized care they need and deserve. 

How many patients could this help?

Ultimately, genetic testing is so important because it can identify the presence of a germline mutation. So far there are 17 documented susceptibility genes which can possess a mutation like this. 40% of all paraganglioma and pheochromocytoma patients have a germline mutation. When not identified, these mutations can be detrimental to patients. 

The real question is that if we’ve known that genetic testing is beneficial for this patient community since the physician guidelines were endorsed by two credible societies then why have we not been doing it?

It’s time to do better. But the good news is that the solution is easy. 

You can read more about this study and the importance of genetic testing within these diagnoses here.

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