Sorry about what had happened.
1. To be honest, none. The 5-year survival rate is less than 4%.
2. Too many differences. You can read more from here:
http://zh.wikipedia.org/zh-hk/%E7%99%8C%E7%97%87
3. Yes based on life expectancy. How many years shortened depends on when the cancer has been discovered.
4. Yes, depending on the body.
In term of treatment, depending on the condition, target therapy may be available (but expensive). If it works, it can significantly increase the survival rate without many side effects. But you will have to discuss with the doctor.
Other than that, for a patient of end-stage cancer, the only thing that can matter (beyond treatment) is quality of life.