Risk Factors for Perioperative Complications, Treatment Outcomes and Aggressive Behavior of the Tumor in Patients with Pheochromocytoma.

Introduction: Pheochromocytomas are catecholamine-secreting tumors arising from chromaffin cells of the adrenal gland. Surgery is the only curative treatment with a high biochemical cure rate, low mortality and high risk of perioperative complications.

Objectives: To study the demographic characteristics of patients with pheochromocytoma and to identify the risk factors for perioperative complications, treatment outcomes, and aggressive behavior of the tumor.

Methodology: We retrospectively studied the data of pheochromocytoma patients registered from 2012 to 2022.

Results: In our study, a total of 30 patients with pheochromocytoma were included. The mean age of presentation was 35 ± 12.8 years. Fifty-six percent were females, and the sex ratio was 1.3:1. Pheochromocytoma spells (60%) was the most common complaint, followed by abdominal pain (53%), orthostatic complaints (10%) and incidentalomas (6%). The baseline mean 24-hour urinary total metanephrines was 2963.7 ± 2658 mcg/24 hours, and the mean tumor size was 7.3 ± 0.53 cm. Forty-three percent of patients underwent laparoscopic adrenalectomy, while the rest underwent open surgery. The mean Pheochromocytoma of Adrenal gland Scaled Score(PASS) was 3.41 ± 0.28, and 23% had a high risk for malignancy. Among perioperative complications, hypertensive crisis (17%) was the most common, followed by postoperative hypotension (13%), hypoglycemia (3%) and right-sided pneumothorax (3%). These patients with complications had higher metanephrine levels (5490 vs. 1880 mcg/24 hours, p = 0.001). Blood pressure normalized in 50%, and this was associated with male sex, younger age (29.5 vs. 40 years, p = 0.03), higher metanephrines (4619 vs. 1855 mcg/24 hours, p = 0.001) and smaller tumors (5.91 vs. 8.61 cm, p = 0.046). PASS score greater than or equal to 4 was associated with higher metanephrine levels (5104 vs. 2312 mcg/24 hours, p = 0.021) and larger tumors (9.28 vs. 6.68 cm, p = 0.024). Biochemical cure rate was achieved in 76% of patients after surgery and was associated with older age (37.7 years vs. 27.7 years, p = 0.047) and absence of pheochromocytoma spells (100% vs. 61%, p = 0.014).

Conclusion: Young age, smaller tumor size and higher metanephrine concentrations were associated with normalization of blood pressure post-surgery. On the other hand, older patients and those without pheochromocytoma spells had better biochemical cure rates. Patients with higher baseline metanephrine levels had increased perioperative complications. More aggressive tumor behavior was associated with higher metanephrine levels and larger tumors. Sex, baseline blood pressure and mode of surgery did not have any influence on treatment outcomes.