Preoperative radiation therapy can be safely omitted for many patients with non-locally advanced rectal cancer, according to a study published today. JAMA Oncology.
Researchers found that a 50% absolute reduction in the use of radiation therapy at the national level did not worsen outcomes for patients with locally advanced rectal cancer.
To examine the impact of reduced use of preoperative radiotherapy, researchers compared two cohorts of patients with non-locally advanced rectal cancer in the Netherlands.
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One cohort was treated in 2011, in which patients with locally advanced rectal cancer routinely received short-term neoadjuvant radiation therapy. The other cohort was treated in 2016, two years after recommendations were changed to the selective use of neoadjuvant radiotherapy for these patients.
The study included cT1-3N0-1M0 rectal cancer patients, with 1199 patients treated in 2011 and 1576 patients treated in 2016. There were no significant differences between the cohorts with respect to age, gender, or American Society of Anesthesiologists classification. However, in 2016 the number of patients with cN1 disease was lower (36%) than in 2011 (40%).
As expected, the use of preoperative radiotherapy, with or without chemotherapy, decreased from 87% in 2011 to 37% in 2016. The use of open surgery similarly decreased from 56% to 11%.
Local recurrence rates and cancer-related mortality rates were similar between cohorts. The 4-year local recurrence rate was 5.8% for the 2011 cohort and 5.5% for the 2016 cohort (P =.99). Cancer-related mortality after 4 years was 7.6% for the 2011 cohort and 8.0% for the 2016 cohort (P =.74).
Disease-free survival and overall survival were higher in the 2016 cohort. The 4-year disease-free survival rate was 67.5% for the 2011 cohort and 75.7% for the 2016 cohort (P <.001). The 4-year overall survival rate was 79.6% for the 2011 cohort and 86.4% for the 2016 cohort (P <.001).
Mortality rates from causes other than cancer were lower in the 2016 cohort than in the 2011 cohort. The 4-year non-cancer mortality rate was 13.8% for the 2011 cohort and 6.3% for the 2016 cohort (P <.001).
Multivariate analysis of the 2011 cohort showed that neoadjuvant (chemo)radiotherapy was associated with a lower risk of local recurrence (hazard ratio). [HR]0.427; 95% CI, 0.218-0.839; P =.01), but not overall survival.
In multivariate analysis of the 2016 cohort, neoadjuvant (chemo)radiotherapy was associated with decreased local recurrence (HR, 0.409; 95% CI, 0.240-0.698; 95% CI, 0.240-0.698, 95 % CI, 0.240-0.698, 95% CI, 0.240-0.698, 95% CI, 0.240-0.698, 95% CI, 0.240-0.698 P <.001), with inferior overall survival (HR, 1.418; 95% CI, 1.086-1.852; P =.01).
“The results of this study demonstrate that with the routine use of magnetic resonance imaging and continued improvements in the quality of rectal cancer surgery, preoperative radiotherapy can be safely omitted in most cases of localized rectal cancer. “This suggests that this is possible,” the researchers wrote.
Disclosure: One study author declared an affiliation with a biotechnology, pharmaceutical, and/or device company. Please refer to the original reference material for a complete list of disclosures.
reference
Hazen S-MJA, Sluckin TC, Intven MPW, and others Waiver of routine radiotherapy for non-locally advanced rectal cancer and oncological outcomes. JAMA Oncor. Published online on December 21, 2023. doi:10.1001/jamaoncol.2023.5444