Intraoperative instability common in pheochromocytomas, paragangliomas despite good preparation

Pheochromocytomas (PCC) and paragangliomas (PGL) show a wide range of symptoms, with frequent intraoperative instability despite good preoperative preparation, according to a Singapore study. In addition, up to one-fifth of the patients in a single centre developed disease recurrences and metastasis.

“Despite maintaining a high standard of preoperative preparation with alpha and beta blockade without any surgical mortality, the incidence of intraoperative haemodynamic instability was 70.4 percent and early postoperative hypotension occurred in 11.1 percent of patients,” the researchers said.

“We found that larger tumour sizes and urinary metanephrine levels elevated by more than two times were associated with intraoperative haemodynamic instability, while tumour sizes >10 cm and elevated urinary normetanephrines were associated with early postoperative hypotension,” they added.

In this study, the researchers identified patients with positive histopathological confirmations of PCC and PGL who were treated at a tertiary Singapore hospital between January 2000 and December 2015. Then, they analysed the results for clinical presentations, treatment, and long-term outcomes.

Of the 27 patients (median age, 57 years, 17 male) identified over a 15-year period, 20 had PCC and seven PGL. One case of PGL developed bilateral disease on follow-up. A positive family history was rare and presented in only 3.7 percent of patients. Palpitations, diaphoresis, and abdominal discomfort were the most common presenting symptoms. [Singapore Med J 2021;doi:10.11622/smedj.2021135]

Of note, intraoperative haemodynamic instability occurred in most patients (70.4 percent), while early postoperative hypotension developed in a few of them (11.1 percent), regardless of adequate preoperative preparation.

Intraoperative haemodynamic instability was associated with large tumour size and higher catecholamine. For instance, a tumour size >5 cm independently predicted this instability (odds ratio, 2.526, 95 percent confidence interval, 1.039–4.768; p=0.019). [QJM 1997;90:51-60; Clin Endocrinol (Oxf) 2018;88:498-505; World J Surg 2014;38:2317-2333; World J Surg 2014;38:2317-2333; Surgery 2016;159:763-770; Surg Endosc 2016;30:2984-2993]

Hypertension and diabetes mellitus were resolved in 41.2 percent (7/17) and 60 percent (3/5) of patients, respectively, after surgery. However, disease recurrence and distant metastases occurred in 22.2 percent and 14.8 percent of patients. Most of them (70.4 percent) were still alive at the end of the follow-up period (median, 35 months, range 3–148).

“Our data reaffirmed our understanding that this tumour presents in a varied manner and that the classical triad described in textbooks is most often absent,” the researchers said.

“We identified two gaps in our current management, namely the ability to predict those who are at risk of perioperative complications and inadequate knowledge on underlying germline mutation associated with PCC/PGL in our population,” they added.

Only one of the patients underwent genetic testing, but the researchers recommended such procedure to those with PCC/PGL and further studies to address such gaps.

The current study was limited by its retrospective design, which could generate potential selection and observer bias, and some missing data, such as preoperative blood pressure readings in five patients and anaesthetic charts in one. In addition, patients managed medically and in the recent 5 years were not included in the review.

“With increased awareness of this condition, as well as the trend towards more PCC/PGL being diagnosed incidentally, the availability of these cases may alter our result,” the researchers said.