INCREASED USE OF LOCAL EXCISION FOR RECTAL CANCER-BE CAREFUL

Recommended treatment for most stage I rectal cancers is total mesorectal excision. However, local excision is considered an alternative for T1 tumors that are < 30% of the bowel circumference, < 3 cm in size, mobile, well to moderately differentiated, and lack lymphovascular invasion in National Comprehensive Cancer Network and American Society of Colorectal Surgeons guidelines. In a study reported inJournal of Clinical Oncology, Karyn B. Stitzenberg, MD, MPH, and colleagues from the University of North Carolina at Chapel Hill examined use of local excision compared with proctectomy in early rectal cancer, finding that use of local excision in higher-risk cancers is increasing and that overall survival is poorer with local excision alone vs proctectomy alone.

Increased Use Over Time

The study included 111,453 patients from the National Cancer Data Base diagnosed with rectal cancer from 1998 to 2010 who did not receive neoadjuvant therapy. Of these, 34,697 (31%) received local excision and 76,756 received proctectomy. Local excision was used in 41% of patients with stage I disease and 7% of those with stage II disease. Local excision use significantly increased over time (P< .001), from 39.8% in 1998 to 62.0% in 2010 in patients with T1 tumors and from 12.2% to 21.4% in patients with T2 tumors.

Factors Associated With Local Excision

Among 46,004 patients with stage I disease, local excision was used in 18,961 (41%), including 46.5% of those with T1 tumors and 17% of those with T2 tumors. Local excision was also more commonly used in women (43%), black patients (52%), very old patients, patients without private health insurance, and patients with well-differentiated tumors.

On multivariate analyses, local excision use was significantly more common in women vs men (odds ratio [OR] = 1.11), patients aged 70 to 79 (OR = 1.22), 80 to 89 (OR = 1.76), and ≥ 90 years (OR = 2.78) vs those aged 50 to 59 years, black vs white patients (OR = 1.39), and uninsured vs private insurance patients (OR = 1.35). Local excision use was significantly less common in patients with moderately differentiated (OR = 0.69) and poorly differentiated (OR = 0.80) vs well-differentiated tumors; patients with T2 vs T1 tumors (OR = 0.26), and patients with a comorbidity score of 1 (OR = 0.76) or 2 (OR = 0.81) vs 0. Patients who underwent proctectomy were significantly more likely to have tumor-free final surgical margins (95% vs 76%, P < .001), with the difference being significant for both T1 and T2 tumors.

Factors Associated With Adjuvant Radiation Therapy

Adjuvant radiation therapy use for stage I tumors decreased over time. On multivariate analyses, use of adjuvant radiation was significantly more common in patients who received local excision vs proctectomy (OR = 5.19), patients aged 40 to 49 years vs those aged 50 to 59 years (OR = 1.18), patients with moderately differentiated (OR = 1.38) and poorly differentiated (OR = 2.10) vs well-differentiated tumors, patients with T2 vs T1 tumors (OR = 3.96), and patients with positive or unknown vs negative margins (OR = 3.14). Adjuvant radiation use was significantly less common in women vs men (OR = 0.87), patients aged 70 to 79 (OR = 0.79), 80 to 89 (OR = 0.45), and ≥ 90 years (OR = 0.18) vs 50 to 59 years, and in patients with a comorbidity score of 1 (OR = 0.83) or 2 (OR = 0.67) vs 0.

Survival

For patients receiving local excision vs proctectomy, unadjusted 30-, 60-, and 90-day mortality was 0.9% vs 1.5%, 1.4% vs 2.1%, and 1.9% vs 2.5%. On multivariate analysis for overall survival, local excision alone was associated with increased risk of death vs proctectomy alone in patients with T1 tumors (hazard ratio [HR] = 1.19, 95% confidence interval [CI] = 1.10–1.28) and patients with T2 tumors (HR = 1.39, 95% CI = 1.26–1.53). There was no significant difference between local excision plus radiation therapy and proctectomy alone for either T1 or T2 tumors, but proctectomy plus radiation therapy was associated with increased risk of death in patients with T1 tumors vs proctectomy alone (HR = 1.28, 95% CI = 1.06–1.54).

The investigators concluded: “Guideline-concordant adoption of [local excision] for treatment of low-risk stage I rectal cancer is increasing. However, use of [local excision] is also increasing for higher-risk rectal cancers that do not meet guideline criteria for [local excision]. Treatment with [local excision] alone is associated with poorer long-term [overall survival]. Additional studies are warranted to understand the factors driving increased use of [local excision].”

The study was supported by National Institutes of Health grants, the Integrated Cancer Information and Surveillance System of University of North Carolina Lineberger Comprehensive Cancer Center, and the University Cancer Research Fund via the state of North Carolina.