All trekkers should ensure that they are covered by adequate travel insurance. The main risks facing trekkers in the Kanchenjunga area are high altitude sickness, and diarrhea.
Both risks, if severe enough will require immediate evacuation to proper medical facilities. Make sure that you insurance covers; Emergency medical treatment, emergency evacuation, and that the policy covers you for the altitudes you will be trekking at.
One of the better insurance companies on offer is World Nomads. They cover you for both medical expenses as well as emergency evacuation up to 6000 m. They do not cover Search and Rescue costs.
If you are bringing a SPOT GPS Satellite beacon you can join the GEOS Search & Rescue program.