The Scottish Medicines Consortium (SMC) decides on Monday whether to approve abiraterone to treat people with prostate cancer.
Scotland is the only part of the UK where patients cannot get the medication which is designed to extend life and improve quality of life for those in the advanced stages of the disease.
Abdelbaset al Megrahi, the Lockerbie bomber, was apparently being treated with drug until his death in May. Justice Secretary Kenny MacAskill released Megrahi from prison on "compassionate grounds" in August 2009 after he was given three months to live.
Abiraterone was already refused to cancer patients in Scotland by the SMC, which blamed its cost, but manufacturer Janssen has re-submitted its application.
Labour and the Conservatives have called on the SMC to reverse its earlier decision. Labour health spokeswoman Jackie Baillie said: "I can only hope the SMC makes the right decision on Monday and allows this drug to be made available in Scotland."
Conservative health spokesman Jackson Carlaw said: "If the SMC does not approve its use, it will make a situation which is already causing severe disadvantage even worse."