Word and/or punctuation missing: 19:57 Aug 16, 2011
The trial by itself does not end when the treatment is over. Treatment is the first phase of the study & THEN the investigators have to follow the patients on a 5-year-off-study-treatment phase to collect information about recurrence & survival.
The TOTAL length of the study IS 5 years AFTER the treatment (+ of course the length of the treatment). Why 5 years? Because, by medical consensus BEFORE this 5-year limit a cancer is considered IN REMISSION, AFTER this limit a cancer is considered CURED.
I'd say that "follow" is the right term here because investigators are actually requested to really "keep in touch" with the patients (phone or mail) since they need to document IMMEDIATELY a recurrence (of cancer) or a belated ocurrence of any adverse event.
The 3-monthly visit actually IS a follow up visit but the investigator NEEDS to follow the patient more closely to get to know immediately if anything happens within the 3-month period. (I.e a recurrence at 1month)
Besides, using "follow-up" may confuse investigators or readers of the trial because in clinical trial terminology "follow-up" refers to all the SCHEDULED follow-up process based on the "patient study calendar". | 
peer agreement (net): +3