Kolstoe, 60, said she and her husband, Paul, 61, had looked forward to the Grand Princess cruise to Hawaii as a brief, badly needed respite from the grind of medical intervention she has endured for the past 18 months.
Now facing the prospect of a two-week quarantine far from their home in Grand Forks, she worries their getaway cruise will end up causing a fateful delay in her next round of chemotherapy, scheduled to begin early next week.
"It's very unsettling," she said in a cellphone interview from the ship on Friday. "It's still a worry that I'm going to not get back."
Besides the implications for cancer treatment is the fear of falling ill from exposure to a respiratory virus especially dangerous to older people with chronic health conditions and suppressed immunity.
"I'm very at risk for this," said Kolstoe, whose rare form of neuroendocrine cancer has spread throughout her body. "Me staying on here for a lot of reasons isn't good."
Kolstoe spoke with Reuters not long after US Vice President Mike Pence, the Trump administration's point man on coronavirus control, announced that 21 of 46 people tested for COVID-19 aboard the Grand Princess were found to be infected. And he said the ship would soon be taken to a non-commercial port where all 3,500 aboard would undergo another round of tests.
The ship was denied entry to the port of San Francisco on Wednesday after state officials learned that some passengers and crew had developed flu-like symptoms, and that the same vessel was linked to coronavirus infections in at least four people on an earlier cruise from San Francisco to Mexico.
"Those that need to be quarantined will be quarantined," including all 1,100 crew members, many of whom may have been exposed to coronavirus during the previous Mexico voyage, Pence said.
But it remained unclear what was in store for passengers who test negative and show no signs or symptoms of the disease.
The uncertainty was clearly taking its toll.
"We can all deal with bad news or whatever kind of news, but we need knowledge to make good decisions, and that's the hard part of this," Kolstoe said. "I probably go... from mad to sad to angry with the cruise ship" and "worried about my health, worried about what it means to not get treatment soon."
She credited the ship's crew with "doing their best," but expressed dismay that passengers were not informed of the test results before Pence announced them on national television. The notice from the ship's captain came 20 minutes later, she said.
Kolstoe, who copes with constant pain, even on her best days, also said she was finding it increasingly difficult to make herself comfortable in the confines of the couple's stateroom.
"We just got a sheet under the doorway [asking] if we need prescription medications in the next seven days," she said. "There's tons of issues. I mean, we all have dirty clothes."
Describing herself as someone who once "loved" taking cruises, Kolstoe said this week's experience has changed her view. "It's probably a risk I can't take anymore," she said.
In the meantime, Kolstoe said she was relying on her faith to help get her through the ordeal.
"God is with me. I know he is," she said. "I recently lost my dad, and I just believe he's up there, going to fix this little situation somehow, and I'm going to test negative and get to go home and get some treatment."