Certain Patients With Rectal Cancer Can Safely Forgo Neoadjuvant Radiotherapy

Many patients with nonlocally advanced rectal cancer can safely forgo neoadjuvant radiotherapy, according to research published in JAMA Oncology.

Researchers found that a 50% absolute decrease in radiotherapy use on a national level did not worsen outcomes in patients with nonlocally advanced rectal cancer.

To determine the effects of a decrease in the use of neoadjuvant radiotherapy, researchers compared 2 cohorts of patients with nonlocally advanced rectal cancer in the Netherlands.

One cohort was treated in 2011, when patients with nonlocally advanced rectal cancer routinely received short-course neoadjuvant radiotherapy. The other cohort was treated in 2016, 2 years after the recommendation was changed to selective use of neoadjuvant radiotherapy in these patients.

The study included patients with cT1-3N0-1M0 rectal cancer — 1199 treated in 2011 and 1576 treated in 2016. There were no significant differences between the cohorts with regard to age, sex, or American Society of Anesthesiologists classification. However, fewer patients had cN1 disease in 2016 (36%) than in 2011 (40%).

As expected, the use of neoadjuvant radiotherapy — with or without chemotherapy —decreased from 87% in 2011 to 37% in 2016. The use of open surgery declined as well, from 56% to 11%.

Rates of local recurrence and cancer-related mortality were similar between the cohorts. The 4-year rate of local recurrence was 5.8% in the 2011 cohort and 5.5% in the 2016 cohort (P =.99). The 4-year cancer-related mortality rate was 7.6% in the 2011 cohort and 8.0% in the 2016 cohort (P =.74).

Disease-free survival and overall survival rates were higher in the 2016 cohort. The 4-year disease-free survival rate was 67.5% in the 2011 cohort and 75.7% in the 2016 cohort (P <.001). The 4-year overall survival rate was 79.6% in the 2011 cohort and 86.4% in the 2016 cohort (P <.001).

The rate of death from causes other than cancer was lower in the 2016 cohort than in the 2011 cohort. The 4-year non-cancer mortality rate was 13.8% in the 2011 cohort and 6.3% in the 2016 cohort (P <.001).

A multivariable analysis of the 2011 cohort showed that neoadjuvant (chemo)radiotherapy was associated with a decreased risk of local recurrence (hazard ratio [HR], 0.427; 95% CI, 0.218-0.839; P =.01) but not overall survival.

In a multivariable analysis of the 2016 cohort, neoadjuvant (chemo)radiotherapy was associated with a decrease in local recurrence (HR, 0.409; 95% CI, 0.240-0.698; P <.001) and inferior overall survival (HR, 1.418; 95% CI, 1.086-1.852; P =.01).

“The results of this study suggest that, with routine use of magnetic resonance imaging and the continued improvement of the quality of rectal cancer surgery, neoadjuvant radiotherapy may safely be omitted for most cases of localized rectal cancer,” the researchers wrote.

Disclosures: One study author declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.

This article originally appeared on Cancer Therapy Advisor