Figures released by Macmillan Cancer Support revealed 43% of sufferers in Berkshire applying for grants from the charity in the last 12 months needed the cash to buy clothing.
In total the charity provided clothing grants of £10,885 to 76 Berkshire people - amounting to £143.22 per person - making it larger than any other payments such as fuel or public transport to cover hospital travel costs.
Weight loss is a common symptom of cancer while certain chemotherapy drugs, steroids, and hormonal therapies can cause weight gain. Patients often need new clothes to accommodate abdominal swellings and colostomy bags, and women require new bras after undergoing mastectomies.
Lyn Holmes, 45, from Hungerford, applied for a grant after piling on three stones during chemotherapy. She said: "It wasn't enough that I had to deal with the illness, the scars, not being able to work through my treatment and all the financial worry that goes with cancer; my clothes were getting tight for me and it made me really paranoid.
"Having that help to buy trousers and tops that fitted me really helped me to get my confidence back when I was feeling insecure about my body."
Charity chief executive Ciarán Devane claimed clothing is the biggest "hidden cost" of cancer and said: "The sheer number of cancer patients turning to us for help towards clothing highlights just how much they struggle financially."
He added: "Patients already have to deal with the physical changes to their bodies - they shouldn't have the added stress of not being able to afford new clothes."
In the last 12 months the charity last year gave a total of £2,105,612 to 14,938 people across Britain towards clothing.
To donate or for extra details on financial support available contact 0808 808 0000 or see www.macmillan.org.uk