A mother of three said she was told by the Department for Work and Pensions (DWP) that she "didn't have cancer enough" when she applied for benefits.
Katie Larn was diagnosed with Hodgkin lymphoma last year, and after starting treatment she applied for Personal Independence Payments (PIP).
The 29-year-old was told she did not qualify for support after a home visit.
A DWP spokesman said it is "committed to ensuring that people with health conditions get the support they need".
"Decisions are made based on all the information that's available to us at the time, including evidence from a claimant's GP or medical specialist," he said.
Ms Larn - who is currently waiting for a date for a tribunal to review her case - told the Local Democracy Reporting Service (LDRS) she believes the assessor who did her home visit thought she was less ill than she was.
"I'd only had one session of chemotherapy then and it was before I'd lost my hair and the steroids had taken effect which made me put weight on," she said.
"I can't help thinking they must have thought I looked alright so I can't have been that bad."
Ms Larn received a letter informing her she would not be receiving PIP six weeks after the visit at her home in Braunstone, Leicestershire, and she said she called the DWP to query the results.
"The man on the phone was really good and explained things to me, I asked him 'So basically I haven't got cancer enough?' and he said yes and that I didn't have enough points to be considered," she said.
Ms Larn is now in remission.
A DWP spokesman said she would continue to receive other benefits while awaiting the outcome of her appeal.