Cancer data

Currently PROSCAR variable has three categories: "Yes", "Suspicious", "No". ASAP variable has three categories: "Yes", "No", "Not applicable". A new variable cancerOccur will contain the following categories: "Yes", "Suspicious/ASAP", "No", "Unknown". Where value "Suspicious/ASAP" is assigned to a subject when either PROSCAR="Suspicious" or ASAP="Yes"; "Unknown" would designate a given subject and procedure date for which all records had ADQU = "Inadequate" (i.e., all the data for that subject was inadequate to make any determination).

• Assumption : The data for a subject is considered adequate if ADQU is missing (ADQU==NA)