The first witness at the Newfoundland and Labrador public inquiry into botched hormone receptor tests told the commission her oncologist withheld information that would have led to a change in the type of breast cancer treatment she was receiving.

Beverly Green, recovering from chemotherapy, wore a knitted wool cap as she took the stand in the makeshift courtroom Wednesday.

She told the inquiry that she turned down antihormone therapy in 2001 because her doctor told her her tests showed it would have been of little benefit.

But when her tissue samples were retested four years later, in 2005, it was discovered that antihormone therapy might have helped her.

For the next two years, Green said nobody told her about the inaccurate results, even as the cancer spread to her liver.

The commission heard how Green became more suspicious as the cancer spread. She said she asked her oncologist if she should reconsider the treatment. Green told the commission how he reacted to her that day.

"And he just turned around at me, and he had the results from my liver biopsy, and he says 'Is this what you want?' and he threw it at me and he walked out the door."

'All about hiding something'

Documents filed with the inquiry showed her oncologist was notified of the mistake in her tests.

But Green said he never discussed it with her, even though her doctor wrote in patient notes that there was a conversation about it.

"They were hiding something. That's my impression," she told the inquiry. "It was all about hiding something. Maybe the issues weren't as large as they were, but because it was being hidden, it drives you in a different direction … right?"

Green has since joined a class-action lawsuit against Eastern Health, the health authority that oversees the pathology labs where the inaccurate testing took place.

She said she wouldn't have resorted to joining the lawsuit if she was told about the mistake from the start.

Over the next few weeks, the commission of inquiry, headed by Justice Margaret Cameron, will investigate why hundreds of hormone receptor tests for breast cancer patients were done incorrectly.

The inaccurate testing caused more than 300 cancer patients to be wrongly excluded from being considered for antihormonal therapies, especially the drug Tamoxifen.