The short answer to this question is no. No you should not ever forego treatment by a qualified and licensed professional for any health issue.
If you came to me for a healing session with a untreated broken arm, I would immediately send you to the emergency room. I might also do ceremony for you to help the healing process, decrease stress or distress, and to ask helping spirits to give you strength.
It would be unethical for any shamanic practitioner to recommend you not seek professional medical help.
Shamanic healing is meant to help treat the spiritual causes of dis-ease, and can often assist healing. But you have a body and a mind too. You have to attend to the needs of the physical.
The put it in esoteric terms - humans are multidimensional being. You live on the physical, mental, and causal plane simultaneously. Shamanic healing works with the interface of the spiritual plane. The help provided there can certainly affect the other dimensions of your being.
You cannot neglect the physical. In many shamanic cultures, the shaman served also as a medicine man. The shaman would not only provide ceremony for healing, but might be trained in setting bones and mixing and distributing medicines.
I do not have the training or the license to practice medicine. I do know physicians with shamanic training - something I think is great.
Strong ethics should be very important to any practitioner.
Just recently I had someone contact me for a healing session. This person had been to a number of practitioners and not gotten any relief. I told this person that I felt it would be unethical for me to have the session. That the problem, most likely, wasn’t an issue of spirit. I wanted this person to seek professional medical help.