Hi Sara,
The results your doctor refers to are mostly from phase II clinical trials, that compared GC to MVAC, which used to be the standard and is now being replaced by GC because it's less toxic. MVAC still has slightly higher response rates, but it's four drugs instead of two, including Platinol (cisplatin, the 'c' in GC/Gemzar-Cisplatin).
The thing with chemo is that the side effects are cumulative, meaning they get worse with each treatment. Not everyone gets these side effects, so maybe your mother will get a break. Also, there are excellent drugs to combat the side effects of nausea and vomiting and there is no reason to suffer through that. Those symptoms usually come a day or two-three after the treatment. Many doctors tell you to take the anti-nausea meds before the nausea gets a chance to strike. Like with pain, it's best to prevent it rather than treat it.
All the best to you and your mother,
Wendy