Cancer research in the news is often associated with sensationalised and inaccurate reporting, which may give rise to false hopes and expectations. The role of study selection for cancer-related news stories is an important but less commonly acknowledged issue, as the outcomes of primary research are generally less reliable than those of meta-analyses and systematic reviews. Few studies have investigated the quality of research that makes the news and no previous analyses of the proportions of primary and secondary research in the news have been found in the literature. We analysed distribution of study types, research sources, reporting quality, gender bias, and national bias in online news reports by four major news outlets in USA, UK and Australia over six-months. We measured significant variation in reporting quality and observed biases in many aspects of cancer research reporting, including the types of study selected for coverage, the spectrum of cancer types, gender of scientists, and geographical source of research represented. We discuss the implications of these findings for guiding accurate, contextual reporting of cancer research, which is critical in helping the public understand complex science, appreciate the outcomes of publicly-funded research, maintain trust, and assist informed decision-making. The striking gender bias observed may compromise high-quality coverage of research by limiting diversity of opinion, reinforces stereotypes and skews public visibility and recognition towards male scientists. Our findings provide useful guidelines for scientists and journalists alike to consider in providing the most informative and accurate reporting of research.