"#dogwgna history in the making," the smiling blonde wrote, adding the hashtags "dogs most wanted, cancer sucks, stay humble pray and it's only hair." A source told ET on Monday that Beth began treatment last month in Los Angeles.
"The [treatments] are going well, but they certainly take their toll on Beth," the source shared. "She's a trooper though and a very tough lady."
Beth found out that her cancer had returned after an emergency surgery she underwent in late November to remove a mass in her throat. Following her surgery, Beth's husband, Duane Lee "Dog" Chapman, kept fans updated on her health on his Facebook.
"'Another bend in the road, yet not the end of the road, #faith, #love #stayhumblepray.' Beth Chapman," Dog wrote alongside a photo of himself next to his wife in a hospital bed.
Meanwhile, the source told ET that Beth and Dog recently started filming for the new WGN America TV series, Dogs Most Wanted, and while the Chapmans "certainly have a lot on their plate" right now, they have been getting a lot of "great support" from their fans and Beth's doctors.
For more on Beth's battle with cancer, watch below.