High incidence of prior cancer in patients newly diagnosed with cancer
medwireNews: A substantial proportion of patients newly diagnosed with incident cancer in the USA have survived a prior cancer, suggest data from the population-based Surveillance, Epidemiology, and End Results (SEER) program.
While the number of cancer survivors in the USA is rapidly growing due to increases in the aging population, an expansion of screening programs, and improvements in therapies, it is nonetheless unclear how many patients diagnosed with incident cancer have survived a prior cancer, say the study authors. Their analysis used SEER data from 2009 to 2013 to remedy this deficit.
Such data are vital, write Caitlin Murphy (University of Texas Southwestern Medical Center, Dallas, USA) and colleagues in JAMA Oncology, as “[u]nderstanding prevalence of prior cancer among patients with different types of incident cancer has important implications for both treatment and research.”
The SEER data reveal that 765,843 incident cancers were diagnosed among the 740,990 individuals included in the study, of which 18.2% were a second-order or higher primary cancer. The prevalence of prior cancer was highest in older adults, at 25.2% among those aged 65 years or older compared with 11.0% among those aged 20–64 years.
Among the younger age group with prior cancer, the most common incident malignancies were myeloid and monocytic leukemia (24.8%), anus, anal canal, and rectum cancers (18.2%), cancers of the cervix and other female genital organs (15.0%), and lung and other respiratory cancers (14.6%).
In the older age group (≥65 years), patients with incident melanoma (36.9%) and myeloid and monocytic leukemia (36.9%) were most likely to have had a prior cancer diagnosis, followed by those with bone and joint cancer (34.0%), and bladder and other urinary cancers (32.5%). In general – although not exclusively – the incident cancer arose at a different site to the prior cancer in both age groups.
“[T]hese findings should spur us to revisit our long-accepted policies of excluding many otherwise well patients with a history of previous early-stage invasive cancer from participation in cancer treatment trials,” said Nancy Davidson (Fred Hutchinson Cancer Research Center, Seattle, Washington, USA) in an accompanying comment.
“In particular these restrictions may greatly limit participation of older patients, the very population where cancer is most commonly diagnosed and where we are most in need of strong evidence to guide treatment.”
By Catherine Booth
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