Effective long-term temozolomide rechallenge in a macroprolactinoma

Area of Science:

• Endocrinology
• Neuro-oncology
• Oncology

Background:

• Prolactinomas, the most common pituitary adenomas, typically exhibit benign behavior and respond well to dopamine agonists like cabergoline.
• However, some cases can develop treatment resistance and aggressive characteristics, necessitating alternative therapeutic strategies.

Purpose of the Study:

• To describe the long-term management of a patient with a macroprolactinoma that became resistant to cabergoline and exhibited aggressive behavior.
• To evaluate the efficacy of multimodal therapy, including surgery, radiotherapy, and temozolomide (TMZ), in managing treatment-resistant aggressive prolactinomas.

Main Methods:

• The study details a 20-year clinical course of a 63-year-old male with a macroprolactinoma.
• Treatment modalities included multiple surgical resections, fractionated radiotherapy, and temozolomide (TMZ).
• The patient received an initial 6-month cycle of TMZ, followed by retreatment upon relapse.

Main Results:

• The patient initially responded to cabergoline for 4 years before developing resistance and aggressive tumor behavior.
• Multimodal therapy, including surgery, radiotherapy, and TMZ, was implemented.
• A relapse occurred after the first TMZ cycle, but the patient responded successfully to a subsequent TMZ retreatment.

Conclusions:

• Aggressive prolactinomas can develop resistance to standard treatments like cabergoline.
• Temozolomide (TMZ) can be an effective treatment option for aggressive and treatment-resistant prolactinomas.
• Multimodal treatment approaches are crucial for managing aggressive pituitary tumors, and successful rechallenge with TMZ is feasible after relapse.