Standard Therapy Beats Out Primary Surgery in Rectal Cancer

TOPLINE:

Patients with locally advanced rectal cancer fare better with standard preoperative chemoradiation followed by surgery than with primary surgery and adjuvant chemoradiation, demonstrating better disease-free survival and lower recurrence rates.

METHODOLOGY:

• The standard treatment of locally advanced rectal cancer is chemoradiation followed by surgery, which is known to reduce the likelihood of local recurrence; however, it is also linked to adverse effects including and bowel/sexual dysfunction.
• A previous trial found that preoperative MRI could delineate tumor involvement of the mesorectal fascia (MRF).
• This Chinese, noninferiority trial tested whether patients with locally advanced rectal cancer with MRI-predicted negative MRF can skip preoperative chemoradiation.
• The study included 275 patients with T3-4aN0 or T1-4aN1-2 rectal adenocarcinoma, an inferior tumor edge 6-12 cm from the anal verge, and gross primary or nodal disease > 1 mm from the MRF — all based on preoperative MRI.
• Patients in the intervention group, 140, were assigned to neoadjuvant chemoradiation (50.4 Gy in 28 fractions with followed by capecitabine/ started 4 weeks after surgery) and the remaining 135 to upfront surgery followed by adjuvant chemo/chemoradiation when there was tumor within 1 mm of circumferential margins.

TAKEAWAY:

• After a median follow-up of 34.6 months, there were six (4.4%) local recurrences in the intervention group and none in the control group.
• In the intention-to-treat population, the 3-year disease-free survival rate was 81.8% in the intervention group vs 85.4% in the control group (hazard ratio [HR], 1.76).
• In the per protocol dataset, the 3-year disease-free survival rate was 81.1% in the primary surgery group vs 86.6% in the preoperative chemoradiation group — a difference of −5.4% (HR, 2.02), prompting the researchers to stop the trial early.

IN PRACTICE:

“This trial was shut down earlier due to an excessive number of [disease-free survival] and local recurrence events observed in the interventional group of primary surgery. Based on our findings, in [locally advanced rectal cancer] patients with high risk though negative MRF, primary surgery would potentially compromise their [disease-free survival] rates. Therefore, primary surgery is an inferior strategy, compared to preoperative [chemoradiation] followed by surgery, and cannot be recommended for [locally advanced rectal cancer] patients in clinical practice,” the authors concluded.

SOURCE:

The study, with first author Jun Li, MD, Department of Colorectal Surgery and Oncology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China, was published online in the International Journal of Radiation Oncology, Biology, Physics.

LIMITATIONS:

The limited sample size will result in compromises in stratified randomization and lower the power for survival analysis. A relatively high proportion of patients (n = 32) crossed over from the neoadjuvant (chemoradiation) group to the primary surgery group. Follow-up time was relatively short, with only 43% of patients completing 3 years of follow-up.

DISCLOSURES:

The study received no commercial funding. The authors had no relevant conflicts of interest.

A version of this article appeared on Medscape.com.