Preoperative treatment selection in rectal cancer: a population-based cohort study

Preoperative radiotherapy and chemoradiotherapy for rectal cancer reduce local recurrence rates but is also associated with side effects. Thus, it is important to identify patients in whom the benefits exceed the risks. This study assessed the pretherapeutic parameters influencing the selection to preoperative treatment.

Data on all patients in the Stockholm-Gotland area, Sweden, who underwent elective trans-abdominal surgery for rectal cancer in 2000-2010, was retrieved from the Regional Cancer Registry and the Swedish National Patient Register. Clinical variables were analysed in relation to selected preoperative therapy. Odds Ratios were derived from univariable and multivariable logistic regression models.

In total 2619 patients were included. Of these 1789 (68.3%) received preoperative radiotherapy or chemoradiotherapy. Over time, use of preoperative therapy increased (p < 0.001). In a multivariable model, age (≥ 80 years) and comorbidity (Charlson Comorbidity Index score ≥ 2) were strongly correlated to omittance of preoperative treatment (OR: 0.05; 95% CI: 0.04-0.07 and 0.29; 95% CI: 0.21-0.39) but there was no difference between genders. Pre-treatment tumour stage was a strong predictor for selection to preoperative (chemo-) radiotherapy. However, 8.2% of patients with intermediate or advanced tumours were selected to no preoperative treatment while 55.0% of patients with early tumours were selected to preoperative therapy.

The use of preoperative (chemo-) radiotherapy increased over time. Suboptimal adherence to guidelines appears to exist leading to a risk of overtreatment and to a small extent also undertreatment. More robust selection criteria, also including age and comorbidity should be developed.