If you don't take risks and avoid the treatment that science isn't 100% on then you significantly slowing down the process of discovering new treatments. For example if the person have terminal cancer and drug A will give another few months to live and experimental drug B may give you years if it works, If it will work it will benefit the society and may or may not benefit the patient but it is a reasonable risk.
Although medical research benefits the future of society, patient care exemplifies the morality of medical practices. People come to doctors to seek medical attention and trust doctors to make decisions and judgement calls based on the interest of the patients.
The primary purpose of medicine is to relieve the suffering of the patient. By performing tests on the patient to advance medical research, the doctor may cause more pain. Also, by testing on the patient in the interest of advancing medical research without the consent of the patient is known as medical exploitation. The patient is at the mercy of the doctor when he/she is ill. The patient depend on the knowledge of the doctor to recover and a corrupt doctor may take advantage of this situation and perform unnecessary test in order to benefit his/her research.
You also need to put into account the question, "why do people seek medical attention?". The creation of medicine is to treat the ill. People come to health care facilities hoping to be cured. It is unethical for the doctor to take advantage of this situation and exploit the patient.
I am doing this to get more idea on what to put in my argumentative paper on "Prioritizing patient treatment vs advancing medical research". So if someone can support or refute my argument, I would greatly appreciate it. Thanks.