On Tuesday last week, Mrs Hawke had a biopsy and the results came back two days later confirming it was melanoma. It was removed on Saturday.
The cancer had just begun growing vertically, a dangerous phase in the growth of the melanoma, and had penetrated 0.6mm into Mrs Hawke's skin.
Mrs Hawke said it was unlikely she would have had a check up any time soon without her sister's intervention.
"It's just amazing timing, she and the doctor saved my life through the goodness of God."
Dr Franz Strydom said finding Mrs Hawke's melanoma was like "catching a hand grenade and throwing it away quickly before it explodes in your hand".
"The moment it starts growing inwards, the deeper it gets, the lower chance you have of being here in five years. Once it gets to 1.5mm, your chance of being here in five years is about 50/50. She got a good prognosis for something that would have been fatal if it wasn't cut out. She's gone from an almost 100 per cent mortality rate to a 93 per cent chance of being here in five years which is a complete turnaround."
Dr Strydom said Mrs Smith was studying towards her diploma in dermoscopy and would end up with the highest qualification a general practitioner could get in the field.
She would not normally treat family but had used her sister as a trial.
"It could have been a very different picture if she hadn't had a skin check.
"It was growing deeply and rapidly. It shows how important skin checks are in the South Pacific."