The prognostic criteria for the efficiency of the long-termed administration of somatostatin analogues
Vyacheslav Pronin1, Eugeny Gitel1, Irina Vasilyeva1, Mikhail Antsiferov2, Tatiana Alexeeva2, Elena Goldman2 & Olga Dorofeeva2
The efficiency of the prolonged medical therapy of acromegaly with the somatostatin analogues (SA) strictly correlates with the initial sensitivity to the drug. Before the onset of SA therapy 114 patients with acromegaly (35 men and 79 women) aged 54 (48/61) years old (Me (25/75%) underwent the test with Octreotide (Sandostatin®): 300 μg sc within 3 days. The decrease of IGF1 level positively correlated with the age of the acromegaly onset (r=0.38) and negatively with the growth hormone (r=−0.23) and IGF1 (r=−0.39) values, as well as with the volume of the tumor (r=−0.39); P<0.001. The patients were distributed into three groups due to the stage of decrease of IGF1 from the initial level (<30, 3160 and >60%). The treatment with Sandostatin® LAR® as a primary or a secondary therapy proceeded within three years in dose of 2040 mg per 28 days. The biochemical remission was defined in 17% of 1st group (7/42), in 44% of the 2nd group (16/36) and in 89% of the 3rd group (32/36) of patients (P1-2=0.012, P1-3,2-3<0.001). The term of remission onset in the 1st and the 3rd groups accounted for 12 (6/24) and 5.5 (3/6) months, respectively; the sufficient dosage in these groups was 40 (30/40) and 20 (20/20) mg, respectively (P1-3<0.001). The positive correlation (r=0.7; P<0.001) was revealed between the value of IGF1 decrease after the test with Octreotide and during the long-termed treatment with SA. The tumor shrinkage in the 1st group was observed in 37%, the stabilization in 22% and the subsequent growth in 41% of the cases. Definitely, the lack of improvement was revealed in patients with the earlier onset of the disease (31 (23/38) vs 42.5 (32/46) years old) and bigger volume of the tumor (4.1 (2.8/6.3) vs 2.4 (1.3/2.8) ml). In the 3rd group the tumor shrinkage was detected in 83%, the stabilization of the growth in 17%, and the worsening in 0% of the cases (P<0.001).
Conclusion: i) The maximum efficiency of the prolonged medical treatment with the SA was observed in patients with later acromegaly onset, lesser volume of the tumor and in patients, sensitive to Octreotide. ii) The compulsory indications for the operative treatment are the younger age of the patients, the big size of the tumor and the resistance to Octreotide. iii) The test with the Octreotide enables to ensure the prognostic criteria of efficiency for the prolonged therapy, as well as to develop the sufficient strategy of the treatment and to determine the starting dosage of the SA.