CDN caching with traffic spikes

Design CDN caching for a news site that gets sudden traffic spikes (10x in minutes when a story breaks) serving mostly static article HTML plus a few personalized fragments. Article HTML can be cached for minutes but must be purgeable within seconds when an editor fixes a factual error. Personalization (logged-in name, region) must not leak between users. Explain your cache-key design, how you protect the origin during a spike, and how you purge fast.