Dear Mr. Kadan
I am Viktor Kadan, Ph.D., Research Scientist of the Institute of Physics, Kiev, Ukraine.
I just as you am interested in the information about the origin of our uncommon surname.
I will be extremely grateful for any comments on the subject. My ancestor came from Kaishovka village Grodno region, Belarus, where this surname is spread among peasant orthodox Christian population. My search in Internet revealed that the bearers of this surname are mostly of Jewish origin, though I am unfortunately not, more exactly know nothing about it.
Perhaps it will be interesting for you to know, that one of Mongol military leaders, grandson of Tengiz Khan, had the name Kadan. He acted in the Eastern Europe, particularly
Grand Ducy of Lithuania, a part of which forms contemporary
There is a small town in Lithuania named Kadan
(it is a Russian spelling,but in Lituanian - Keidan) (Re.: A Hole in the Heart keidan.net;http://mywebpages.comcast.net/acassel/keidan/
Descriere: The 500-year history of Keidan, a vanished Jewish community in Lithuania).
Perhaps this surname comes from this town.