[14] In 1997 he became the Chief of the Cancer Program of the World Health Organization[9] before resigning in 1999 over a disagreement with the UN regarding their proposals to restructure work on non-communicable diseases, stating this would create a "top-heavy bureaucracy".
Sikora is known for his outspoken views on National Health Service (NHS) reform,[18] and has written for the Times,[24] the Observer,[25] the New Statesman,[26] and other publications on the subject.
[30] Sikora later told The Guardian that he did not know his interview would be used in the ad campaign, and that he agreed with Obama that the main problems with the American system were "the high cost of medical treatment" and the large number of uninsured people.
[30] In a piece published online by the New Hampshire Union Leader the same day as the advertisement, Sikora was referred to as professor of oncology at Imperial College.
[34][35] In the context of the National Institute for Health and Care Excellence (NICE) considering whether to apply age criteria when prescribing expensive drugs, he suggested that "within limited budgets" younger patients might be given priority over the frail elderly.
[40] He is also a "professional member" of the College of Medicine, a patient-oriented healthcare lobby group also linked to the Prince of Wales that appeared shortly after the collapse of the FIH.
[50] Sikora has however, elsewhere been critical of alternative medicine; after Parliament member Lord Maurice Saatchi proposed a bill allowing doctors to use unproven experimental therapies, he noted that this could give false hope to terminally ill patients.
The Daily Telegraph reported that Sikora, along with Professors Jonathan Waxman and Ibrahim Sharif, was one of three doctors hired by the Libyan government to assess Megrahi's condition prior to the release.
[56] Sikora has since complained about the way journalists have reported his views and stated that he was not paid to make claims,[57] and there was probably a less than one percent chance of Megrahi living 10 years.
[59][60][61] On 21 September 2020, Sikora alongside Carl Heneghan, Sunetra Gupta and 28 other signatories, wrote an open letter to top UK government officials asking for a rethink to the Covid strategy.