The revelation comes after it was confirmed the singer WILL be performing tonight after last weekend's injury.
Anastacia revealed she had ripped scar tissue in her chest, leaving her unable to perform in the dance off.
As a result, the elimination decision between Anastacia and Melvin Odoom reverted to the public vote. With the fewest votes, Melvin was eliminated.
Following a visit to doctors this week, Anastacia was given the all clear to dance as her representative vowed she would never quit.
"[On Monday], Anastacia visited the clinic of a specialist in breast reconstruction surgery. The doctor again confirmed that there was a tear in the scar tissue, which although painful is not permanent," they said in a statement.
Anastacia's spokesperson continued: "She was given the all-clear to dance this weekend with the caveat that the routine is carefully choreographed and she has been given the appropriate medication. Brendan was with her for her appointments and they have been filmed for this weekend's episode.
"The specialist will be monitoring her condition regularly, and she will revisit them on Monday.
"She is doing this to raise money for breast cancer, so unless a doctor tells her she can't carry on, quitting would never be an option."
Anastacia has unfortunately had to battle breast cancer twice, first in 2003 and then again in 2013 when she had to undergo a double mastectomy.
Speaking at the Strictly launch last month, Anastacia first announced her intention to give her fee from the show to charity.
The US performer said she wanted to "give as much as I can back to the women and to a cure" in a bid to "make a difference.".
"I'm going to try to ask as many of my mates that might have a couple of extra dollars to match what I make," Anastacia added to the BBC News website. "So whatever I end up making I just want them to match it."
Strictly Come Dancing continues tonight, live on BBC One from 6:45PM.