After an abrupt departure from Good Morning America nearly three weeks ago, co-anchor Robin Roberts resumed her reporting duties August 20.

In June, Roberts, 51, was diagnosed with myelodysplastic syndrome (MDS), a rare blood and bone marrow disorder. During her brief absence, the ABC journalist continued her pre-treatment for a bone marrow transplant.

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"My needle was past 'E' when I left here a couple of weeks ago, but I've got a full tank, so watch out," Roberts told viewers. "I haven't taken this much time off in quite some time."

During her time off, Roberts helped raise money for cancer research in California, visited friends and family in Mississippi and celebrated a friend's 50th birthday in Italy. Thanks to her high-profile position, Roberts even secured special access to the Vatican, where she prayed at the altar the pope uses before addressing the crowd from his balcony.

"I was saying a special prayer for all those who have lifted me up in prayer," Roberts explained. During her trip, Roberts tweeted that she was "grateful to Italy for renewing my spirit/soul."

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Roberts continued to receive treatment during her temporary leave, though the PICC line -- a catheter used in chemotherapy -- was removed from her arm. She will undergo surgery for a bone marrow transplant from her sister in a few weeks, at which point Roberts will go on a longer medical leave.

Roberts -- who battled breast cancer five years ago -- thanked her Twitter followers for a "great welcome back" August 20. "Going right now to tape a PSA for Be the Match," she wrote. "Bone marrow donors (like my sis) are saving lives."

This article originally appeared on Robin Roberts Returns to Good Morning America After Temporary Leave