Can a polypoid on the vocal cords diminish in size with proper voice rest and speech therapy? i would prefer to avoid surgery, if i know that my singing voice can improve with proper voice rest and speech therapy. i am a professional singer.

It : It is certainly possible, and the prefered management strategy, in the professional singer. Surgery always runs some risk of creating scar tissue on the vocal fold and affecting oscillation of the mucosal wave. Proper vocal hygiene that includes rest, vocal retraining, adequate hydration, and control of factors that can incite laryngeal irritation ( i.e., acid reflux, post-nasal drainage, second hand smoke, chemical irritants, etc.) is a good starting point. Having clean high efficiency filters on your furnace with good humidity control is also helpful. Larger polyps, or those that don't regress, can be treated with minimally invasive endolaryngeal surgery using microflap techniques and conservative co2 laser application.

Vocal cord polyp: Vocal cord polyps have been observed to resolve with conservative care. Laryngologists with the best microscopes and lasers usually can accomplish excellent clinical results if resection proves necessary. A good speech pathologist should coach you in strategies for voice rest - it's quite difficult!