Should lanreotide (Somatostatin analogue) for acromegaly be restarted after radiotherapy?

From the Guidelines

Lanreotide should typically be continued after radiotherapy for acromegaly, with the goal of gradually tapering it as radiotherapy takes effect. Following radiotherapy, it often takes 5-15 years for full radiation effects to normalize growth hormone (GH) and insulin-like growth factor-1 (IGF-1) levels [ 1 ]. During this period, continued medical therapy with lanreotide (typically 60-120 mg deep subcutaneous injection every 4 weeks) is usually necessary to control symptoms and biochemical markers.

Key Considerations

• Regular monitoring of GH and IGF-1 levels every 3-6 months is recommended to assess disease control and guide potential dose adjustments [ 1 ].
• As radiotherapy effects become established and hormone levels normalize, physicians may attempt to reduce the lanreotide dose or extend the interval between injections, with the possibility of eventual discontinuation if biochemical control is maintained [ 1 ].
• This approach is necessary because radiotherapy works gradually by destroying pituitary tumor cells over time, while lanreotide provides immediate suppression of GH secretion and symptom control [ 1 ].
• However, patients should be monitored for potential hypopituitarism developing as a side effect of radiotherapy, which may require additional hormone replacement therapies [ 1 ].

Monitoring and Adjustment

• IGF1 monitoring is necessary with repeat biochemical (oral glucose tolerance tests) and radiological (MRI) assessment if recurrence is suspected [ 1 ].
• Close interaction between paediatric and adult endocrine services is required to coordinate long-term medical care and the transition to adult services [ 1 ].
• After radiotherapy, at first 6-monthly and later 12-monthly follow-ups should monitor the patient for the development of hypopituitarism or recurrence [ 1 ].

From the Research

Restarting Lanreotide after Radiotherapy

• The decision to restart lanreotide (Somatostatin analogue) for acromegaly after radiotherapy depends on various factors, including the patient's response to previous treatments and the presence of any side effects 2, 3.
• Studies have shown that lanreotide is an effective treatment for acromegaly, with antisecretory efficacy reported in 35%-70% of cases 4.
• Radiotherapy is often used as an adjunctive therapy after unsuccessful surgery, and it can lower GH levels and normalize IGF-I levels, but it has a long lag time before this effect is achieved 2, 5.
• The use of lanreotide in combination with radiotherapy has not been extensively studied, but it is possible that lanreotide could be restarted after radiotherapy to control GH and IGF-I levels 3, 6.
• A study on the use of slow release lanreotide (30 mg) for 24 months in acromegalic patients showed that the treatment was effective in reducing GH and IGF-I levels, and it was well tolerated by the majority of patients 6.

Considerations for Restarting Lanreotide

• The patient's previous response to lanreotide and radiotherapy should be taken into account when deciding whether to restart lanreotide 2, 4.
• The presence of any side effects, such as gastrointestinal discomfort or increased risk of gallstone formation, should also be considered 4, 6.
• The goals of treatment, including normalizing GH and IGF-I levels, reducing tumor size, and relieving symptoms, should be evaluated when deciding whether to restart lanreotide 2, 5.
• The potential benefits and risks of restarting lanreotide after radiotherapy should be weighed, including the possibility of improved disease control and the risk of adverse effects 3, 6.