Good Morning America” posted its biggest lead over “Today” show in 18 years last week, “GMA” network ABC boasted Friday morning when the Nielsen stats came in.

 What ABC did not say was that last week marked the scheduled, and yet dramatic, bow-out of co-anchor Robin Roberts, who was leaving to get a bone marrow transplant as part of her treatment for myelodysplastic syndrome.

And, if that wasn’t dramatic enough, Roberts suddenly announced on-air, on Thursday of last week, that she was leaving a day early in order to visit her ailing 88-year-old mother, who died that night.

 Pathos-packed “GMA” not only beat NBC’s “Today” in all five head-to-head broadcasts last week, it did so with its largest overall audience in 16 months – since Royal Wedding Week. “GMA” has now ranked No. 1 for the past three weeks, and 8 of the past 10 weeks, trailing an Olympics-fueled “Today” the other two weeks.