As well as research, Professor Dixon is the director of skin cancer education at a college he founded in Docklands. He was trained in medicine at the University of Melbourne and holds several fellowships in his field. The papers make a radical claim about diagnosing melanoma, rejecting aspects of national guidelines for checking if a patient's cancer has spread to other parts of the body. Currently, according to the national guidelines, patients are given a sentinel node biopsy, which involves cutting out a lymph node in their armpit and examining it under a microscope. Professor Dixon claims the surgery does not work and comes with serious side-effects, including chronic pain and nerve damage. He argues for an ultrasound examination. Critics say Professor Dixon’s preferred method of ultrasound examination "failed to diagnose metastic melanoma in the sentinel nodes of 92.9 per cent" of cancer patients.

After Professor Dixon’s articles were published in June, 18 of Australia’s top skin cancer specialists, including the CEO of the Cancer Council, wrote to the journal demanding the papers be immediately withdrawn. The articles could "result in inappropriate treatment of melanoma patients and to worse survival outcomes," they wrote in a letter to the journal. After an investigation, The Australian Journal of General Practice agreed and retracted the papers in October. They contained "a large number of factual errors that undermined the reliability of the overall article," the journal said in a retraction note published online. "There is no allegation of misconduct of any type on the part of the authors, simply errors. The decision to retract the articles was based around patient-safety, which is our primary concern," the journal's editor-in-chief Professor Stephen Margolis said.

Professor Dixon is co-founder of the Australasian College of Cutaneous Oncology in Docklands, which promotes itself as the leaders in research and training of skin cancer management. The college offers a "suite of skin cancer workshops" — including the dermoscopy program on board a European cruise ship — all accredited by the Royal Australian College of GPs. Other workshops are held at Docklands. Professor Dixon explained that it was often cheaper to offer a course on a ship, rather than a traditional conference centre, because he did not have to pay for catering. The workshops cost $990, not including the price of the cruise. The most recent workshop that was organised on a cruise ship trip took place in September on board the 91,000-tonne Celebrity Infinity, which cruised from Barcelona to Rome. As well as his opposition to sentinel node biopsies, Professor Dixon also believes the benefits of several cancer drugs are being oversold.

Reached in Barbados, Professor Dixon hit back at his critics. "Australian cancer patients are being told they are required, obligated, demanded, necessitated to have added surgery despite it being recognised that such surgery does not alter survival," he told The Age and The Sydney Morning Herald. "Other patients are being urged to have surgery that does not improve their survival in order to receive drugs that might." Professor Dixon demanded the journal reinstate his papers. He also called for the resignation of the journal's editor, the CEO of the Cancer Council and the rest of his critics. He sent The Age two letters, one signed by 17 Australian GPs who specialise in skin cancer and the other by 16 cancer researchers at the University of California, defending his work.