Androgen Withdrawal Phenomenon

Androgen Withdrawal Phenomenon

Urology relation: Treatment of Prostate cancer
Definition
A decrease in PSA level after withdrawal of antiandrogens from patients showing objective responses to combination therapy (LHRH agonist and antiandrogens)

Drugs:
1.      Flutamide
2.      Bicalutamide
3.      Nilutamide
4.      cypertrone acetate
5.      DES
6.      Progestational agents

PSA decline phenomena
-        Time: within 4 to 6 wks
-        Amount: up to 50 % (in 15 to 30%)
-        Duration: 3.5 - 5 months

Explanation:
Mutation of AR that make antiandrogen act an agonistic function.

Evidence:
-        (Suzuki; 1996) A Point mutation of AR in PCa cell line that allow flutamide to increase proliferation was found in PCa sample of PCa from patients with AWP .
-        (Hara; 2003) similar point mutation found in cases have Bicalutamide act as agonist.
-        (Bohl; 2005) X ray crystallography shows that bicalutamide bind to mutant AR just like DHT bind to nirmal AR.

Applications:
1.   Associated measurable tumor response: not common
2.  Overall survival: not affected
3.  Act a confounding effect on clinical trials
4.  Predictors: those with rapid response of PSA after androgen ablation.

_________________________________________
Ahmed Bakr, MD, FEBU
Egypt



Comments

  1. Well-acclaimed for his professional approach towards the patients, Dr. Dushiant Sharma is one of the most experienced and widely practising urologist in Panchkula involved in the identification and treatment of the disorders related with the urinary system. He actively applies the modern profound knowledge of up-to-date achievements in the sphere of medicine.

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