Predictors and Outcomes of Upstaging in Rectal Cancer Patients Who Did Not Receive Preoperative Therapy

BACKGROUND: Preoperative chemoradiation is indicated for clinical stage II and III rectal cancers; however, the accuracy of clinical staging with preoperative imaging is imperfect. OBJECTIVE: The study aimed to better characterize the incidence and management of clinical and pathologic stage discordances in patients who did not receive preoperative chemoradiation. DESIGN: This was a retrospective cohort analysis. SETTINGS: The source of data was the National Cancer Database from 2006 to 2015. PATIENTS: We identified patients who underwent resection with curative intent for clinical stage I rectal adenocarcinoma without preoperative chemotherapy or radiation. MAIN OUTCOME MEASURES: We evaluated the characteristics of upstaged patients-those with T3/T4 tumors found on pathology (pathologic stage II) and/or with positive regional nodes in the resection specimen (pathologic stage III) compared with those patients who were not upstaged (pathologic stage I). We then used a mixed-effects multivariable survival model to compare overall survival between these groups. RESULTS: Among 7818 clinical stage I rectal cancer patients who did not receive preoperative therapy, tumor upstaging occurred in 819 (10.6%) and nodal upstaging occurred in 1612 (20.8%). Upstaged patients were more likely than those not upstaged to have higher grade tumors and positive margins. Survival was worse in upstaged patients (hazard ratio [HR], 1.64; 95% CI, 1.4-1.9) but improved among those upstaged patients who received either chemotherapy (HR, 0.71; 95% CI, 0.6-0.9) or chemoradiation (HR, 0.62; 95% CI, 0.5-0.7). LIMITATIONS: In addition to the inherent limitations of a retrospective cohort study, the National Cancer Database does not record functional outcomes, local recurrence, or disease-specific survival, so we are restricted to the evaluation of overall survival as an oncologic outcome. CONCLUSIONS: Inaccurate preoperative staging remains a common clinical challenge in the management of rectal cancer. Survival among upstaged patients is improved among those who receive recommended postoperative chemotherapy and/or chemoradiation, yet many patients do not receive guideline-concordant care. See Video Abstract at https://links.lww.com/DCR/B999.

Automated summary

The study examined patients with clinical stage I rectal adenocarcinoma who did not receive preoperative chemoradiation. It found that tumor upstaging occurred in 10.6% of patients and nodal upstaging occurred in 20.8% of patients. Upstaged patients had higher grade tumors and positive margins. Survival was worse in upstaged patients, but improved with postoperative chemotherapy and/or chemoradiation.