Applying for PhD overseas After a Break I am a Graduate in Life sciences who has been working in a corporate job for the past 2+ years.

I am currently researching and aiming to apply for PhD programmes in Europe. In requirements for PhD I have come across the need for Recommendation letters from past supervisors.

It has been over three years since I worked under a Research supervisor. And I feel it would not be appropriate to ask them after a long term.

Are there any means by which I can proceed without recommendation letters ?
How will this affect my chances for acceptance?
Actually, I think it is a mistake to try to submit without letters. People will wonder about your motives and worry that you don't think you can get good recommenders. 

Your break isn't that long, actually. After 20 years it would be different. Your old professors probably still remember you if you did good work. Of course, you will need to reintroduce yourself, bring them up to date on what you have done recently, and remind them of what you did in the past. 

But, assuming that you had a good enough relationship back then to have asked, that hasn't changed. It is certainly appropriate to do so. Many professors, in fact, are happy to hear about old students and to support their further advancement.