It is true that many young women eventually die from breast cancer.
And it is true that some may die from opportunistic infections which
gain ground in the body due to immune system suppression resulting from
chemotherapy. But this is a rarer occurrence than dying from the
disease itself. More often it is an unchecked, aggressive form of
spreading cancer that kills young women, which for some reason is not
amenable to any of the treatments. It relentlessly pursues the body
until death.
Deaths from secondary infections most often come from a delay in
receiving immediate health care once symptoms strike. The episode
showed Dana receiving good in-patient medical care within a few hours
of her symptoms. Portraying her as dying from the infection anyway
might unnecessarily frighten viewer/patients from selecting
chemotherapy in the first place, should such a diagnosis befall them.
I know it's easy to jeer from the cheap seats out here, but I think
this story line unnecessarily diverted attention towards modes of
treatment (i.e., to receive chemotherapy or not) rather than to put it
where it belongs: the horror of the cancer itself.