January 25, 2017
3 min read

Adjuvant chemotherapy may be overused in younger patients with colon cancer

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Young and middle-aged patients with colon cancer are two to eight times more likely to receive postoperative chemotherapy compared with older patients, according to results of a cohort study.

However, adjuvant chemotherapy yielded no added survival benefit for these patients.

Because prognosis of colon cancer in young patients is often unclear, adjuvant chemotherapy may be overused, according to Kangmin Zhu, PhD, MD, from the division of military epidemiology and population sciences at John P. Murtha Cancer Center of Walter Reed National Military Medical Center–Bethesda, and colleagues. Although previous studies have suggested younger patients are more likely to receive aggressive care, these studies derived their data from national databases. Because receipt of treatment is related to insurance status, the results of prior studies may be confounded by insurance status and types.

“A study that compares receipt of adjuvant chemotherapy among different age groups in an equal-access health care system, in which members are more similar and have comparable access to medical care, is warranted,” the researchers wrote. “An examination in an equal-access health care system can minimize the potential effects of insurance status and types, thus providing additional evidence concerning the effect of age on the use of adjuvant chemotherapy and its benefits.”

Researchers evaluated the medical claims database and cancer registry of the U.S. Department of Defense Military Health System to determine associations between receipt of adjuvant chemotherapy by age category in 3,143 patients aged 18 to 49 years, 50 to 64 years, and 65 to 75 years. Researchers compared the first two age groups, young and middle-aged patients, with the latter.

A greater proportion of young (69.3%) and middle-aged patients (53.1%) received postoperative chemotherapy than older patients (42.4%).

After adjusting for potential confounders, young and middle-aged patients were two to eight times more likely to receive postoperative systemic chemotherapy compared with older patients across all tumor stages.

Adjuvant chemotherapy receipt was more common among young patients with stage I (OR = 7.98; 95% CI, 2.88-22.11), stage II (OR = 4.22; 95% CI, 2.23-7.98), stage III (OR = 2.3; 95% CI, 1.01-5.22) and stage IV (OR = 2.43; 95% CI, 1.26-4.7) disease than among older patients.

Similarly, middle-aged patients with stage I (OR = 5.04; 95%CI, 2.3-11.05) and stage II

(OR = 2.42; 95%CI, 1.58-3.72) disease were more likely than older patients to receive postoperative chemotherapy.

In addition, young (OR = 2.48; 95%CI, 1.42-4.32) and middle-aged (OR = 2.66; 95%CI, 1.7-4.18) patients were more likely than older patients to receive multiagent chemotherapy, “suggesting a tendency toward more intense treatments,” the researchers wrote.

Of patients who were treated with surgery alone, survival outcomes improved among middle-aged patients with stage I (HR = 0.29; 95% CI, 0.13-0.62) and stage IV (HR = 0.47; 95% CI, 0.22-0.98) disease, and among younger patients with stage III disease (HR = 0.01; 95% CI, 0.01-0.89) compared with their older counterparts.

Patients who received surgery and postoperative systemic chemotherapy demonstrated no

significant differences in survival among age groups.

Zhu and colleagues noted the overuse of adjuvant chemotherapy may hinder patients’ quality of life and implicate economic burdens.

“Patients may undergo decreased physical, functional, emotional and social well-being, although these changes might be mitigated over time,” they wrote. “In addition to the effects on patients’ quality of life, overuse of chemotherapy increases economic burdens on society because the cost of chemotherapy for colon cancer is high. Therefore, appropriate use of chemotherapy in colon cancer treatment should be investigated and evaluated in further research.”

However, the definition of the age groups in the study are open to criticism because the researchers used the current practice cutoff of age 50 years for screening, Tonia M. Young-Fadok, MD, MS, from the Mayo Clinic College of Medicine in Phoenix, Arizona, wrote in an accompanying editorial.

“Further investigation of the discrepancies in stage II [disease] would be worthwhile, and additional research on the age discrepancies in stage I disease would not only be interesting but also mandatory,” she wrote.

Therefore, Young-Fadok called upon an expansion of the scope of tumor boards.

“Appropriate treatment is vital for a patient’s survival, but excess treatment may increase complications and is a poor stewardship of health care funds,” she added. “...This is also a clear call for improved oversight of chemotherapy for colon cancer.” – by Kristie L. Kahl

Disclosure: The researchers and Young-Fadok report no relevant financial disclosures.