The finding reflects research showing up to 40 per cent of oncologists would hesitate to inform a patient of a drug, which might cost up to $1000 a week.

University of Sydney associate professor of medical oncology Fran Boyle said many oncologists felt it was kinder not to mention expensive drugs not subsidised on the Pharmaceutical Benefits Scheme.

Professor Boyle said some of these drugs might increase the chances of curing a patient or extend their survival.

''Oncologists are in a terrible dilemma,'' she said.

''If they say to the patient, 'Here's an option for your treatment, but the cost is going to be exorbitant' is that going to add so much to the distress of that patient, when they're already in a vulnerable position?''

Professor Boyle, an oncologist at Mater Hospital in Sydney, spoke to fellow oncologists at a Clinical Oncological Society meeting in Sydney yesterday.

She said cancer patients wanted them to be more up-front about available drug treatments. Several participants in the study had found out about a drug after being treated, which they thought would have been useful in their recovery.

They described this as a real breach of trust, Professor Boyle said. ''Almost all the women we surveyed, 96 per cent, said they wanted to be informed about high-cost drugs, whether or not they could afford them,'' she said.

Gillian Horton, of Bruce, was diagnosed with breast cancer in April this year. The Bosom Buddies member and mother of three will undergo her last chemotherapy session on Friday.

Mrs Horton said she learned early on after her diagnosis that how she was treated was her choice.

''If I don't have all the facts, how can I make an informed decision?'' she said. ''If I find out later there was perhaps a drug which was more beneficial and that I wasn't given that, that would really, really distress me. It would be the 'what if?'.''