Broccoli nutritious value

Learnt today. Broccoli good points:
rich in Vitamin C.
anti-cancer element.
reduces prostate cancer risk.
source of calcium.

However wikipedia states that Broccoli when boiled may loose half its nutritious value.

Whfoods has however said that the anti-cancer activity is at its best if you cut the florets and stems thinner and let it sit 5-10 mins before cooking. Lightly steamed /cooked broccoli will still retain its anti-cancer power as well as its Vitamin C and makes it easier to digest.