We've had pizza once since my 9 year old daughter has been on the pump. We didn't get ideal readings but they were okay and gave us a starting point. Remember everyone is different so you may not experience the same effect but here are her readings for information, maybe it will be helpful:
7pm - BG reading of 5.0 mmol/L. Pizza with a glass of fresh orange juice. Insulin split 35% 65%. The 35% was delivered immediately, the remaining 65% being delivered over 3 hours.
8pm - BG reading 6.8 mmol/L
9pm - BG reading 8.4 mmol/L
10pm - BG reading 6.5 mmol/L
11pm - BG reading 8.8 mmol/L - BG correction
1.30am - BG reading 12.0 mmol/L - BG correction plus +10% temp basal set for 4 hours
3am - BG reading 9.0 mmol/L - BG correction
5am - BG reading 8.0 mmol/L - BG correction
7.30am - BG reading 4.7 mmol/L
Rest of the day her readings were back to normal.
I know from past experience that pasta and pizza send her reading up high long after she's eaten, like 6+ hours until about 10 hours later. Next time we try pizza I'll do a similar extended bolus but after about 3-4 hours I'll set another temporary basal to last maybe 5-6 hours at about +20%.