Surgical strategies in endocrine tumors

Abstract

Endocrine surgery has become more custom-made throughout the years. Endocrine tumors can be sporadic or develop as part of familial syndromes. Several familial syndromes are known to cause endocrine tumors. The most common are multiple endocrine neoplasia (MEN) syndromes type 1, 2A and 2B. This thesis addresses the currently available surgical strategies in the management of endocrine tumors. The studies described in this thesis offer more insight in the prognostic implications of several factors in endocrine cancers and the surgical treatment of endocrine cancer. The following matters have been studied. For thyroid cancer we have studied the currently known diagnostic markers and prognostic factors and the expression on matrix metalloproteinases. In patients with recurrent papillary thyroid cancer we have studied the influence of fluorodeoxyglucose-positron emission tomography (PET) scan positive lesions on the prognosis and implications for surgical management. It appears that patients with recurrent papillary thyroid cancer that have PET positive lesions have a worse prognosis than those who have PET negative lesions. The surgical treatment for patients with recurrent papillary thyroid cancer that have PET positive lesions should be aggressive. For patients with Multiple Endocrine Neoplasia Type 2A we studied the factors that determine outcome after total thyroidectomy for medullary thyroid cancer. A higher age and type of codon (918 and 634) are the most important prognostic factors and are associated with persistent and recurrent medullary thyroid cancer. For the parathyroid glands, we determined the optimal surgical treatment of primary hyperparathyroidism in MEN 1 and MEN2A. For MEN 1 patients, a subtotal parathyroidectomy is recommended, whereas for MEN 2A patients, a minimally invasive parathyroidectomy is recommended, because the clinical presentation is less aggressive. For the pancreas a systematic review was conducted to determine the timing and best surgical strategy for pancreatic endocrine tumors in MEN 1 patients. Even after a systematic review it remains difficult to recommend a clear cut indications and type of surgical procedure for pancreatic endocrine tumors in MEN1. Adrenal gland surgery was also studied. A cost-effectiveness analysis was carried out for retroperitoneal endoscopic versus conventional open adrenalectomy followed by a large series of posterior retroperitoneal adrenalectomies, in which the procedure was shown to be safe and effective. Finally, the clinical spectrum in terms of hormone levels and clinical presentation of pheochromocytoma was studied. The size of pheochromocytoma correlate to the levels of cathecholamine production especially up to 4cm. The largest tumors produce the highest hormone ratios. From this thesis, it can be concluded that the management of patients who have an endocrine tumor is complex and individual. The treatment of these patients has become tailor-made more and more throughout the years. Patients with familial endocrine syndromes should be regarded as distinctly different from patients with sporadic endocrine disease and often require a different and more aggressive approach. These patients and their families are entitled to centralized care with a multidisciplinary team of endocrinologists and endocrine surgeons.