Definitely not, if there is an Ethics Committee, you have to consult it. Obviously these studies referred to must refer to patients, logically that a decision in this field goes through a detailed analysis of the principles of Bioethics that compromises values of the entire health system of any country, so you can not disregard the opinion of the Committee for a decision in this field.
It's a common misunderstanding. Many researchers who have not been exposed to research ethics think of the Ethical Approval as a bureaucratic formality, so any permission should do.
We the... (fill in the blank as you wish) should do more to raise the awareness about the general picture and the greater role of the the ethical review and its role in the protection of the participants and the researchers alike.