Colon cancer treatment, survival improving in older patients

The quality of care received by older patients with colon cancer has significantly improved since 2001, but adherence to treatment guidelines could still be increased to further improve outcomes, according to new research published in Cancer.

“It’s been shown that patients with colon cancer have better survival outcomes when receiving guideline-recommended treatment,” Hui Zhao, PhD, assistant professor of Health Services Research at The University of Texas MD Anderson Cancer Center, said in a press release. “Therefore, it was important for us to characterize adherence-to-treatment guidelines to monitor the quality of care in Texas. Interestingly, we found surgical adherence has improved quite a lot since 2001, but for chemotherapy, the line is almost flat.”

Treatment guidelines recommend that patients with stage II colon cancer undergo colectomy with removal of at least 12 lymph nodes, and that patients with stage III colon cancer receive chemotherapy (5-fluorouracil [5-FU] with leucovorin or capecitabine) in addition to colectomy and lymphadenectomy, according to the press release.

To determine adherence to these guidelines for patients older than 65 years, Zhao and colleagues reviewed Medicare-linked data from the Texas Cancer Registry on 2,161 patients diagnosed with stage II colon cancer and 3,868 patients diagnosed with stage III colon cancer between 2001 and 2011. All patients underwent colectomy within 6 months of their diagnosis.

Overall, 51% of patients with stage II colon cancer and 30% of patients with stage III disease received guideline-recommended treatment.

Among all patients, 64.4% received guideline-recommended surgical treatment, and the rate of surgical guideline adherence increased from 47.2% to 84% throughout the study period.

Conversely, only 50.3% of patients with stage III disease received guideline-recommended chemotherapy treatments, and these adherence rates increased modestly from 48.9% to 53.1%.

“I was surprised by these results, because there is a clear benefit to the patient from receiving guideline-concordant therapy,” Zhao said in the press release. “Our study reinforces previous data showing that adherence is associated with improved survival, which is important for patients to be aware of.”

Specifically, Zhao and colleagues reported that patients with stage II disease who received guideline-recommended treatment showed an 87% 5-year survival rate vs. 77% of those who received surgical treatment that did not adhere to guidelines. Patients with stage III disease who received guideline-recommended treatment showed a 73% 5-year survival rate vs. 62% among those who received only recommended surgery, and 55% among those who received surgical treatment that did not adhere to guidelines.

Accounting for demographic and tumor characteristics, the investigators found guideline-adherent treatment was associated with improved cancer cause-specific survival for patients with both stage II and III colon cancer.

Further, they found that patients who received surgical treatment that adhered to guidelines were more likely to be married, have stage III disease, large tumor size, and have their surgery performed by a colorectal specialist surgeon.

Patients who did not receive recommended adjuvant chemotherapy were more likely to be men older than 75 years with higher comorbidity and lower socioeconomic status. For example, patients who had Medicare covered by a state buy-in program — which is available for patients with income up to 135% of the federal poverty level, per the press release — were 18% less likely to receive guideline-recommended chemotherapy.

“Our study reinforces the need for providers to have open discussions about risks and benefits so that our patients can make informed decisions about their care,” Sharon Giordano, MD, chair of Health Services Research and professor of breast medical oncology at MD Anderson Cancer Center, said in the press release. “To ensure quality care, we must also work to improve access to care wherever possible, reducing or eliminating barriers that prevent patients from receiving appropriate treatments.”

The investigators noted that the findings may not be generalized to younger patients or those living in other parts of the country, as the study included only older patients from Texas. Future research in larger population samples is required to address these and other limitations, they added. – by Adam Leitenberger

Disclosures: Giordano and Zhao report no relevant financial disclosures. One of the study authors reports she was supported by a grant from the Cancer Prevention Research Institute of Texas for work performed as part of the current study.