If this were me, I would put it in the form of a complaint in writing. You could do this to the attending doctor's office and also the patient advocacy service if there is one? Once it is "official" the doctor concerned will be forced to act if only to mitigate his own liability.

The other thing you could do is turn up at emergency and demand the completion of your treatment. This would work but it would be even more stressful and frustrating for you as you are likely to have to sit for hours again.

So sorry you are going through this - I understand your frustration (not a strong enough word, I know) and can only commiserate. Alex and I had similar issues when his lung collapsed. Alex's condition deteriorated until surgery became the only (and most dangerous) option. All because the damn registrar was too frightened to call the consultant in on a weekend.

People started moving when I made an official complaint to the hospital via the patient advocate and let them know that if anything happened to Alex, I would be pursuing the cardiothoracic department with everything I had. The head of department took over Alex's case and moved appointments so that he could see Alex himself at Alex's convenience. Alex could barely stand up at the time and I refused to allow him to sit in a waiting room with other patients with his immune system as weak as it was.

If you do decide to put your situation in writing, outline your fear of the infection either progressing or impacting on your treatment, and cc as many people as you can think of - your oncologist would be an obvious one, but possibly also the team nurse and the home care people.