Editorial: Novel Methods for Measuring Global Cancer Burden: Implications for Global Cancer Control

 JAMA Oncology 

"Because cancer can occur in young people and creates significant disability prior to death, the social impact as measured by disability-adjusted life-years (DALYs) is staggering."

....In oncology, diagnostic accuracy is a critical issue for developing cancer treatment strategies. Cancer registries are linked to surgical pathology assessments. While some cancers may be amenable to accurate diagnosis through clinical evaluation or simple diagnostic testing, most cancers can be difficult to specify in the absence of tissue diagnosis. The GBD investigators provide estimates of years of life lost for different cancers, some of which showed little change in ranking over the study years (eg, lung, colon, breast, esophagus, ovarian, uterine, melanoma), whereas others had marked variation in rank order (eg, pancreatic, bladder, gall bladder, Hodgkin lymphoma, myeloma). These variations in the latter group could reflect differences in cancer prevalence, biology, and/or treatment but may alternatively relate to diagnostic inaccuracy, because all of the cancers with variations in rank order require higher-quality imaging studies and/or pathology assessment for definitive diagnosis. Histologically different cancers that present in adjacent anatomic locations and/or with similar signs and symptoms could easily be confused. Without histologic evidence confirming malignant tissue diagnosis, mortality causation assessment tools cannot reliably differentiate between primary liver cancer, gall bladder cancer, pancreatic cancer, and cancer metastatic to liver, all of which have similar clinical presentations. Because accurate tissue diagnosis is fundamental to cancer registry methodology but is not required in GBD analysis, the GBD approach developed by IHME seems unlikely to achieve the diagnostic precision of a pure cancer registry–based method. These findings highlight the importance for strengthening global pathology and imaging services in conjunction with expanding cancer registration data systems throughout the world, which could benefit both GLOBOCAN and GBD estimates........