Cancer is a scary battle for anyone to undergo, as actress Shannen Doherty has learned in the last year and a half. She was diagnosed with breast cancer in February 2015, but the battle has lately become even more intense because the disease has spread outside of her breasts.

“I had breast cancer that spread to the lymph nodes, and from one of my surgeries we discovered that some of the cancer cells might have actually gone out of the lymph nodes,” the “Beverly Hills, 90210” actress tells ET. “So for that reason, we are doing chemo, and then after chemo, I’ll do radiation.”

She says the scariest part is that there are no guarantees any of these treatments will work.

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“The unknown is always the scariest part. Is the chemo going to work? Is the radiation going to work? You know, am I going to have to go through this again, or am I going to get secondary cancer?” she says. “Everything else is manageable. Pain is manageable, you know living without a breast is manageable, it’s the worry of your future and how your future is going to affect the people that you love.”

The actress reveals that she had a single mastectomy in May, which was hard on her, especially getting fitted for her new bra.

“I broke down crying in the dressing room and ran out and then sat in the car crying.”

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Doherty is currently right in the middle of her eight rounds of chemo. She recently took to Instagram to document shaving her head, hoping that she can help others out there who are experiencing the same struggle.

“After my second treatment, my hair was really matted, like dreadlocks, and I went to brush it and it just fell out. I just remember holding on to just huge clumps of my hair in my hands and just running to my mom, crying, ‘My hair, my hair, my hair.’ … we finally had to get the shaver thing and just buzz it off,” she says, adding that she wanted to have the agency of showing her fans what the process was like.

“I didn’t want somebody to take a picture of me coming out of the grocery store and be like, ‘Oh God, look at her.’ I wanted to put it out there the way that it felt the best for me to put it out there. And if I could help one person then it makes me go oh, OK. It makes it easier to live with having cancer if I know I’m helping at least one person.”