L. E. Hendrick1, J. D. Buckner1, W. M. Guerrero1, D. Shibata1, N. M. Hinkle1, J. J. Monroe1, E. S. Glazer1, J. L. Deneve1, P. V. Dickson1 1University of Tennessee Health Science Center,Department Of Surgery,Memphis, TN, USA
Introduction:
In the United States, patients with clinical stage II or III rectal cancer typically receive neoadjuvant chemoradiation therapy (chemo/XRT) over a 5-6 week period followed by a 6-10 week break prior to proctectomy. The chemotherapy administered with radiation is delivered at radio-sensitizing doses. Thus, it is essentially standard for these patients to have a 3-month window between initial staging and primary tumor resection, while potential systemic disease is left untreated. The purpose of the current study was to evaluate the utilization of restaging studies in detection of disease progression during this window.
Methods:
We performed a single institution retrospective review of patients with clinical stage II/III rectal cancer from 2005-17. Data were abstracted for demographics, initial staging modalities, type and timing of neoadjuvant therapy, restaging modalities and time interval to restaging, surgical management, and adjuvant therapy. We excluded patients with clinical stage I or IV disease, inadequate/incomplete clinical staging, and those receiving short-course or no pre-operative chemo/XRT. Characteristics of patients that developed metastatic disease were examined. Statistical analysis was performed with bivariate analysis using Fischer’s exact test (significance level set at p<0.05).
Results:
We identified 176 patients with clinical stage II (65, 37%) or III (111, 63%) rectal adenocarcinoma that completed neoadjuvant chemo/XRT. Among these, 110 patients underwent some form of restaging study either pre-operatively or within 30 days following proctectomy and before adjuvant therapy. Restaging included CT CAP in 101 (57%), MRI pelvis in 16 (9%), EUS in 9 (5%), PET/CT in 4 (2%), proctoscopy in 9 (5%), and multiple modalities in 23 (13%). Gender, age, race, insurance status, clinical stage, histologic grade, and tumor location (high vs mid vs low) were similar between patients who did and did not have restaging performed (p>0.05). Among all patients restaged, 6 (5.5%) had newly detected distant metastases including liver (2), lung (3), and multiple sites (1). No patient was found to have local progression on restaging. Of the patients with progression, metastases were detected on CT CAP in 5 and PET/CT in 1. Gender, age, race, insurance status, clinical stage, histologic grade, and tumor location (high vs mid vs low) were similar between patients with and without identification of disease progression (p>0.05).
Conclusion:
In patients with clinical stage II/III rectal cancer who undergo standard neoadjuvant chemo/XRT, peri-operative restaging with CT CAP and/or PET/CT detects new metastases in a small percentage of patients. Future investigation with multi-institutional collaboration to include a larger patient cohort may help better identify clinicopathologic factors predictive of detecting disease progression.