The IARC Monographs: Updated Procedures for Modern and Transparent Evidence Synthesis in Cancer Hazard Identification.

The Monographs produced by the International Agency for Research on Cancer (IARC) apply rigorous procedures for the scientific review and evaluation of carcinogenic hazards by independent experts. The Preamble to the IARC Monographs, which outlines these procedures, was updated in 2019, following recommendations of a 2018 expert advisory group. This article presents the key features of the updated Preamble, a major milestone that will enable IARC to take advantage of recent scientific and procedural advances made during the 12 years since the last Preamble amendments. The updated Preamble formalizes important developments already being pioneered in the Monographs program. These developments were taken forward in a clarified and strengthened process for identifying, reviewing, evaluating, and integrating evidence to identify causes of human cancer. The advancements adopted include the strengthening of systematic review methodologies; greater emphasis on mechanistic evidence, based on key characteristics of carcinogens; greater consideration of quality and informativeness in the critical evaluation of epidemiological studies, including their exposure assessment methods; improved harmonization of evaluation criteria for the different evidence streams; and a single-step process of integrating evidence on cancer in humans, cancer in experimental animals, and mechanisms for reaching overall evaluations. In all, the updated Preamble underpins a stronger and more transparent method for the identification of carcinogenic hazards, the essential first step in cancer prevention.

A Prospective Analysis of Red and Processed Meat Consumption and Risk of Colorectal Cancer in Women.

BACKGROUND: Red and processed meats have been implicated as risk factors in the development of colorectal cancer in U.S. women, but associations with cooking practices are less well established. METHODS: Data are from the Sister Study, a cohort of women ages 35 to 74 years from the United States and Puerto Rico who have a sister diagnosed with breast cancer. Red and processed meat consumption, meat cooking practices, and intake of common meat products were collected at baseline using self-administered questionnaires (N = 48,704). Multivariable HRs (HRadj) and 95% confidence intervals (95% CI) were estimated. RESULTS: During a median 8.7 years' follow-up (range <1-12.7 years), 216 colorectal cancer cases were diagnosed. In categorical analyses, an increased risk of colorectal cancer was seen in the highest quartile of processed meat consumption compared with the lowest [HRadj = 1.52 (95% CI, 1.01-2.30); P trend = 0.02], and for specific meat products, including breakfast sausages [HRadj = 1.85 (95% CI, 1.30-2.64)] and bacon [HRadj = 1.46 (95% CI, 1.01-2.11)]. The HRadj for the highest quartile of red meat consumption was 1.04 (95% CI, 0.68-1.60), and little evidence of association was observed for cooking practices or doneness of red meat. We observed positive associations with specific red meat products when cooking methods were considered, for example, grilled/barbequed steaks [HRadj = 2.23 (95% CI, 1.20-4.14)] and hamburgers [HRadj = 1.98 (95% CI, 1.00-3.91)]. CONCLUSIONS: Higher reported daily intake of processed meats and consumption of barbecued/grilled red meat products were associated with increased risk of colorectal cancer in women. IMPACT: Variability in colorectal risk risk by meat type and cooking method should be considered when evaluating meat consumption.