Adjuvant Chemotherapy Overuse Highlighted In Young Colon Cancer Patients

Overuse of adjuvant chemotherapy in colon adenocarcinoma patients aged less than 50 years does not greatly improve their survival

medwireNews: Overtreatment is common in young colon cancer patients but offers little or no benefit to prognosis and may impact long-term survivorship, suggests analysis of US patients treated outside of clinical trials.

The real-world study included data for 13,102 patients aged 18 to 49 years at diagnosis and 37,007 patients aged 65 to 75 years between 2003 and 2005. All the patients underwent resection, and postoperative chemotherapy if deemed necessary, with curative intent.

Y Nancy You, from The University of Texas MD Anderson Cancer Center in Houston, and co-authors note that the majority of patients with young-onset colon cancer had advanced disease at diagnosis.

Indeed, 36.5% and 25.3% of young patients had stage III and IV disease, respectively, compared with just 30.3% and 15.7% of those with later-onset colon cancer.

Young patients were significantly more likely to receive postoperative systemic chemotherapy than their older counterparts regardless of tumour stage (66.3 vs 39.8%). In particular, early-onset patients were 2.88, 4.22 and 3.93 times more likely than later-onset patients to receive adjuvant chemotherapy for stage I, stage II low-risk disease and any stage II disease, respectively.

“These practices represent overtreatment because current evidence does not support chemotherapy in stage I disease and indicates a controversial role of chemotherapy in stage II disease”, the researchers write.

Young patients were also significantly more likely than older patients to receive multi-agent chemotherapy, such as oxaliplatin- or irinotecan-based regimens, for stage II, III and IV disease.

Although initial analysis indicated young patients had a poorer prognosis than older patients, after adjusting for the more advanced stage at diagnosis and other tumour and patient factors, their stage-specific prognosis was “equivalent or slightly better”, the researchers observe.

Adjusted 5-year survival for patients with stage I colon cancer treated with surgery alone was better for patients with early-onset than later-onset disease (98.4 vs 96.8%), as was survival for patients with stage II disease treated with surgery alone (86.9 vs 82.3%).

However, the adjusted 5-year survival rates for overall stage II and stage II low-risk patients who received surgery plus adjuvant chemotherapy did not significantly differ between young and older patients (91.1 vs 90.2% and 95.2 vs 95.4%, respectively).

And adjusted 5-year survival rates for patients with stage III or IV disease who received postoperative chemotherapy were only “marginally more favorable” in early-onset than later-onset patients (73.7 vs 71.0% and 21.1 vs 16.0%, respectively).

“The minimal survival differences were unmatched by the significantly greater patterns of overtreatment in the young”, Y Nancy You et al therefore conclude.

They caution: “We highlight the potential for lingering treatment-associated toxicities in young cancer survivors and suggest that their potentially unique survivorship warrants specific investigation.”

Reference

Kneuertz PJ, Chang GJ, Hu C-Y,et al. Overtreatment of young adults with colon cancer. More intense treatments with unmatched survival gains. JAMA Surg 2015; Advance online publication 25 March. doi:10.1001/jamasurg.2014.3572

medwireNews (www.medwireNews.com) is an independent clinical news service provided by Springer Healthcare Limited.© Springer Healthcare Ltd; 2015