Young and middle-aged patients with colon cancer are up to eight times more likely to receive postoperative systemic chemotherapy than patients aged 65 years and older, a large cohort study has found. The postoperative chemotherapy does not improve survival, which begs the question – is it being overused in younger colon cancer patients?
The findings were published online January 25 in JAMA Surgery.
The cohort of young and middle-age patients were also 2.5 times more likely to receive multiagent chemotherapy than older patients across all tumor stages, notes the research team, led by Kangmin Zhu, MD, PhD, professor, Department of Preventive Medicine and Biostatistics, the Uniformed Services University of the Health Sciences, Bethesda, Maryland.
Multiagent chemotherapy is not currently recommended for most patients with early-stage colon cancer, they note.
"While younger patients who underwent surgery tended to have better survival than older patients, the addition of postoperative systemic chemotherapy did not result in matched survival improvement," the researchers note.
"Our findings suggest overtreatment of young and middle-aged adults with colon cancer," they coclude.
The study's findings have significant clinical and economic implications, because patients with cancer are vulnerable to the adverse effects of chemotherapy toxicity. Quality of life can be reduced, and physical, functional, social, and emotional well-being can be affected, the researchers say.
In addition, the cost of chemotherapy for colon cancer is high, and overuse can create economic burdens. "Appropriate use of chemotherapy in colon cancer treatment should be investigated and evaluated in further research," they conclude.
In an email, Dr Zhu said that whether younger patients with colon cancer are overtreated with chemotherapy "is an emerging topic in research," and he echoed the study conclusions that "more research is warranted."
Incidence and Mortality Rates Decreasing
The incidence and mortality rates of colorectal cancer among adults aged 50 years and older have decreased in the United States, probably as a result of colorectal screening programs, the researchers point out. Adjuvant chemotherapy is recommended for stage III and IV tumors and can significantly increase disease-free survival in patients with stage III colon cancer.
The same cannot be said for young patients with colon cancer. Prognosis is not well known in this group, Dr Zhu and colleagues note. Even less is known about the benefits of adjuvant chemotherapy in earlier-stage cancer, and it is not the standard of care.
"Treatment options for patients with young-onset colon cancer have yet to be defined, and their effects on prognosis are unclear," the researchers say. "Nevertheless, a considerable proportion of patients are still receiving this treatment.
The group's study findings are consistent with a 2015 study report published in JAMA Surgery that suggested that chemotherapy for colon cancer may be overused in young patients who do not benefit from any improvement in survival.
Dr Zhu and colleagues wanted to see whether they could demonstrate the same findings using data from a healthcare system in which all members had a similar level of access to medical care. This would reduce the potential effects of insurance status and types on the research results, Dr Zhu explained.
The researchers mined the medical claims databases of the Central Cancer Registry and Military Heath System of the US Department of Defense.They identified 3134 patients between the ages of 18 and 75 years with histologically confirmed primary colon adenocarcinoma.
All patients had been diagnosed between January 1, 1998, and December 31, 2007.
Patients were categorized into three groups on the basis of age at onset of colon cancer. Patients aged 18 to 49 years were classified as "young," those 50 to 64 years of age were considered "middle-aged," and those 65 to 75 years of age were "older."
The study included 671 young patients; 1599 were middle-aged, and 873 were older. Just more than half of the patients (58.6%) were men.
Younger patients (aged 18 to 49 years) were less likely to be male and non-Hispanic white and were more likely to be married. They were also more likely to have cancer at earlier stages at diagnosis and fewer morbidities than persons aged 50 years and older.
When compared to older patients, young and middle-aged patients were more likely to have tumors of overlapping or unknown locations and were less likely to have right-sided tumors.
After adjusting for the potential confounders, 69.3% of young patients received postoperative systemic chemotherapy compared to 53.1% of middle-aged patients and 42.4% of older patients.
Survival status was similar for young and middle-aged patients, at 72.0% and 71.6% alive, respectively, and was lower for older patients, at 61.4% alive.
The odds ratios (OR) were 7.98, 4.22, 2.30, and 2.43 for young patients compared with older patients with tumors of stages I, II, III, and IV, respectively. Middle-aged patients with stage I (OR, 5.04) and stage II (OR, 2.42) disease were more likely to receive postoperative chemotherapy compared with older patients.
In older patients, physicians are often reluctant to recommend chemotherapy or more intensive regimens because of comorbid diseases and the greater toll that adverse effects of treatment can take, the researchers note.
In young patients who do not have the same health challenges, however, physicians may be more likely to recommend chemotherapy, they point out. One small study showed that younger patients also tend to be much more proactive in disease management than older patients and want to be involved in treatment decisions.
JAMA Surg. Published online January 25, 2017
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