The Bachelorette 's Katie Thurston Opens Up about Chest Scar from Undergoing a Lumpectomy at 20

Katie Thurston is encouraging her followers to always advocate for their own health.

On Wednesday, the Bachelorette, 30, shared a selfie on her Instagram Story, showing off a scar on her chest that she said she often receives questions about.

"It's from a lumpectomy after finding a lump in my breast. Because I was only 20, I discovered this on my own," she wrote. "Typically women don't get routine mammograms until their 40s, so it's important to be your biggest advocate when it comes to your personal health."

Thurston then highlighted the L4 Project, which was founded by Bachelorette suitor Michael Allio in memory of his wife, Laura, after she died of breast cancer in 2019.

The organization supports programs aimed at helping families and patients with cancer diagnoses so they "can focus on treatment and recovery more successfully." Before her death, Laura was "steadfast" in her mission to encourage others to advocate for their own health, according to the project's mission.

Katie Thurston/INSTAGRAM

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Allio unexpectedly exited Thurston's season during Monday night's episode, before he had the chance to make it to her final four suitors.

The choice to leave came after a heartbreaking phone call with his 4-year-old son James, in which the little boy wondered aloud whether his dad didn't want to see him.

"It was obviously a really difficult decision [to leave the show]," Allio told PEOPLE earlier this week. "But as a parent, it was black and white."

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He continued, "When your child says that, you answer the call. And I think a lot of single parents probably have to deal with the fact that when they're pursuing their own happiness, it does take a little bit from the time they're spending with their child. It's a constant balancing act that's happening. But I would do it all over again and make the same decisions."

Getting to sit down with Thurston during the Men Tell All special gave him the "closure" he was longing for, he added.

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"I've been waiting to have this conversation with Katie for a while — I mean, since the day I left New Mexico, it's been on my mind. She did provide clarity for me to be able to begin starting over and finding [love] all over again."