Source: The Lancet
In the USA, cancer is the most common cause of death in people aged between 49 and 80 years. In 2007, 562 875 cancer deaths were reported, which account for about 23% of all deaths. Cancers of the lung, colorectum, breast, and prostate are the most common and have the highest mortalities. In high-income countries remarkable progress has been made in cancer management and care, and although cancer incidence continues to rise, due to the influences of ageing, lifestyle, and population growth, mortality has fallen and survival rates are improving for several cancers, largely because of advances in screening, early detection, and treatment.
So in light of this progress, the US Centers for Disease Control and Prevention (CDC) report published last week makes for troubling reading, showing as it does that almost half of colorectal and cervical cancers and a third of breast cancers are being diagnosed at a late stage when treatment is less effective. The study is the first nationwide examination of stage-specific cancer incidence rates and screening prevalence for breast, cervical, and colorectal cancer by demographics including age and race or ethnic origin. The study found a lower uptake of screening and the presentation of symptoms late in low-income and ethnic minority communities, who also had longer delays in getting their diagnosis and treatment after an abnormal test. All these factors have been well documented to be associated with a late diagnosis for over a decade, so it is disappointing to see that cancer care is still failing the same patient groups. A further finding was the wide variation in late-stage diagnosis across different locations, which is a sad reflection of the fragmented health-care system in the USA. The CDC also reported that people without appropriate health insurance had less access to services despite the Patient Protection and Affordable
Care Act that is supposed to cover recommended screening tests by supporting people financially through co-payments.
Patient delay can be a major factor behind late diagnosis; many patients are unaware of (or ignore) the symptoms of cancer; and health literacy, cultural attitudes towards seeking medical care, fear and embarrassment of a cancer diagnosis, and difficulties navigating the health-care system all play a part. But physicians can add to delays by failing to recognise sentinel signs and by failing to triage the right patients forward for further investigation. Symptoms of early cancer can be non-specific and mistaken for other conditions, a factor behind the late presentation of ovarian or pancreatic cancers, for example. Biomarkers could have a role in helping to identify and stratify high-risk populations. Education of both the patient and general physician is essential to move to an early diagnosis of cancer. For example, if patients have a family history of certain cancers, such as colorectal or breast cancer, then these individuals can present earlier than might be expected. Both patient and physician should be aware of these indicators and appropriate screening programmes made available to all who need them.
A shortcoming of the CDC report is the lack of discussion about the nature of diagnostic tests and the challenges they present. For colorectal cancer, the fecal occult blood test is not discriminative, and the follow-up tests of sigmoidoscopy or colonoscopy are invasive and not without risk. Although, encouragingly, the recent trial of once-only flexible sigmoidoscopy screening has been shown to be safe and practical. However, overdiagnosis and overtreatment can limit the effectiveness of screening in the general population; thus, identification of high-risk groups is crucial. There is a need for better initiatives to support the development of specific tests for particular cancers and to direct treatment to specific patient groups.
Several initiatives to promote early diagnosis in symptomatic patients are noted in the report and should be credited. The CDC have recently established the Colorectal Cancer Control Program, which provides funding to 25 states and four tribal organisations to promote screening and follow-up care to low-income individuals who are uninsured for screening. The CDC’s National Comprehensive Cancer Control Program provides funding and technical assistance to all states and minority community organisations to develop and implement coordinated cancer control plans to provide a continuum of services including prevention, early detection, treatment, survival, and palliation.
Efforts to identify people most at risk of cancer and those who are difficult to reach must continue to be a priority if the alarming statistics in the CDC report are to improve. More research aimed at improving diagnostic tests and biomarker development would complement and improve early clinical diagnoses, and should go hand-in-hand with the removal of patient and physician barriers to effective cancer care.