'The Office' star Jenna Fisher, 50, reveals breast cancer diagnosis

Jenna Fisher shares the news of her breast cancer diagnosis.

The “Office” star, 50, took to her Instagram on Oct. 8, writing that since October is Breast Cancer Awareness Month, she wanted to share her story.

“I never thought I would make such an announcement but here we are. Last December, I was diagnosed with stage 1 triple positive breast cancer. After completing surgery, chemotherapy and radiation I am now cancer free,” she wrote in her caption. “I wanted a photo of myself in my patchy pixie looking happy and healthy to go with this news.”

Fisher added in her caption that the slides on her Instagram post contained more information about her breast cancer journey.

She said she had a routine mammogram last year and encouraged others to do the same. Then doctors discovered “something in my left breast,” she recalled.

She noted that her type of breast cancer is aggressive but responsive to treatment. Stage 1 means the cancer has not yet spread to the lymph nodes or the rest of the body. She underwent a lumpectomy to remove the tumor in January, followed by 12 rounds of chemotherapy and three weeks of radiation. He is now cancer free but continues to take medication.

“I'm happy to say I feel great,” she wrote.

Fisher, who is a mother of two children, ages 10 and 13, said that before she decided to share her diagnosis, she wore a wig after losing her hair during chemotherapy.

“I am making this announcement for a few reasons. One, I'm ready to ditch the wigs. Two, urging you to get your annual mammogram,” he wrote.

“I'm serious, call your doctor right now,” he continued. “My tumor was so small it couldn't be felt on physical exam. If I had waited six months, things could have gotten worse. It could have spread.”

“Seeing women posting pictures of their mammogram appointments on Instagram required me to set my own (which I was late for). I'm so glad I did. Consider it a kick in your butt for getting it done.”

“I'm also sharing this in hopes that it will be a source of support for any woman going through this right now. As anyone who's been diagnosed with cancer knows, your life changes immediately.”

The actor thanked his “amazing village” from the medical team that helped him survive the cancer he was attached to, as well as his friends and family, including his best friend and fellow “The Office” star Angela Kinsey.

She also mentioned her husband, Lee Kirk, who has “been by my side through it all.” After her final chemo and radiation treatments, he asked her how she wanted to celebrate. He replied that he wanted to “ring a bell with the kids, in our backyard, with everyone throwing confetti.”

The final image of his slideshow is of that moment.

What is triple positive breast cancer?

Triple-positive breast cancer occurs when cancer cells have high levels of the HER2 protein, as well as receptors for the hormones estrogen and progesterone, according to BreastCancer.org. This means that when estrogen, progesterone or HER2 proteins bind to cancer cells, they grow faster.

As a result, these types of cancers are considered aggressive, but they respond better to treatment than triple-negative breast cancers, which tend to be worse.

Treatment for triple-positive breast cancer usually includes surgery, such as a mastectomy or lumpectomy, radiation, chemotherapy, drugs that target the HER2 protein, and hormonal therapy.