Cancer registration data plays a major role in the design and monitoring of cancer control activities and policies, and population-based cancer registries (PBCR) are the main source of information. In developed countries, the healthcare infrastructure enables the registration of quality cancer data. In low and middle Income countries (LMIC), where health care facilities are limited or scarce, cancer registration data may be of low quality. The aim of this article is to demonstrate the value of cancer incidence data for LMIC, even when quality is questionable, as well as to attempt to interpret the messages that the quality indicators convey both for cancer registration and the healthcare system. The study of data submitted to the Cancer incidence in five continents, volume nine (CI5-IX) leads to the conclusion that when PBCR from LMIC cannot provide good quality data it may indicate a deficiency that goes above and beyond the registrar ability. The quality control indicators evaluated provide insight on local conditions for cancer diagnosis and care. Low data quality not only signals lack of collaboration among reporting sources and the inability of the registrar to perform quality abstracting, but also points to specific weaknesses of the cancer care system and can guide improvement goals and efforts.