A ruling on whether a health trust was right to refuse a breast cancer patient a potentially life-saving drug is due in the Court of Appeal.
Ann Marie Rogers is in the early stages of breast cancer
Ann Marie Rogers, 54, of Swindon, Wilts, appealed against a High Court decision upholding Swindon Primary Care Trust's refusal to fund Herceptin.
The trust said it refused Ms Rogers the drug as it was not licensed for the early-stage breast cancer she has.
But Ms Rogers says she faces a "death sentence" without it.
Her lawyers argue that the primary care trust's decision was "arbitrary in the extreme" because the cancer expert treating her had recommended that she receive the drug.
But lawyers for the trust said the decision had been taken after advice was sought from the local cancer network and that it was in line with the advice of the strategic health authority.
High Court judge Mr Justice Bean found Swindon's decision to refuse the drug was not unlawful.
However, he said he knew there were different opinions on whether or not to prescribe Herceptin to patients with early-stage breast cancer.
He added: "The court's task is not to say which policy is better, but to decide whether Swindon's policy is arbitrary or irrational and thus unlawful."
The appeal court's decision could mean every primary care trust in the country is required to fund Herceptin for early stage breast cancer patients.
Alternatively, the judge could limit it to Ms Roger's case.
Herceptin targets the HER-2 protein, which can fuel the growth of breast tumours.
Around a fifth of breast cancers are HER-2 positive.
The treatment is currently licensed for the treatment of advanced breast cancer but not for early-stage breast cancer, which research has suggested it could also help.
Full treatment with Herceptin costs an estimated £20,000 a year.
During the High Court case, Swindon Primary Care Trust insisted its decision had not been made on the basis of economics.
But managers said they would only fund the course of treatment if they felt the patient was "exceptional".
Speaking before last month's appeal court hearing, Ms Rogers said: "I am facing a death sentence if I cannot receive Herceptin.
"This battle against the bureaucracy created by hospital managers to receive the drug that my clinician has prescribed for me, has taken its toll and I am placing my faith in the court."
Her solicitor Yogi Amin said health authorities across the country adopted different policies on whether or not to prescribe Herceptin.
He called on Health Secretary Patricia Hewitt to end what he called a "grossly unfair postcode lottery".
"Breast cancer patients want to ensure that their access to life-saving drugs, which their doctors prescribe, will not be overruled by a group of financial managers who decide whether they can be deemed an 'exceptional' person and that their life is 'exceptional' in some way.
"There is no good reason for the health authority to ration this essential drug treatment."
Makers Roche submitted their licence application for early-stage breast cancer to European drug authorities in February.
Once that is granted, NHS drugs watchdog the National Institute for Health and Clinical Excellence (NICE) promised to fast-track its appraisal if Herceptin is cost-effective
That process is set to be completed later this year.