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PREDICTORS OF NEOADJUVANT THERAPY IN CLINICAL T2N0M0 RECTAL CANCER AND ASSOCIATIONS WITH SPHINCTER PRESERVATION - A NATIONAL SURGICAL QUALITY IMPROVEMENT PROGRAM DATABASE ANALYSIS (NSQIP)
Andrea P. Solis- Pazmino
*2, Joshua H. Wolf
3, Vincent Xu
2, Rachel Ma
2, Joseph Wetherell
3, Matthew P. Zeller
3, Moshe Barnajian
1, Jessica Felton
3, Yosef Nasseri
1,21Surgery, Cedars Sinai Medical Center, Los Angeles, CA; 2Surgery Group Los Angeles, Los Angeles, CA; 3Sinai Hospital, Baltimore, MD
Background: Current guidelines do not recommend use of neoadjuvant chemoradiotherapy (NACR) in cT2N0M0 rectal cancer. Nonetheless, patients with low cT2N0M0 rectal cancer may be offered NACR to regress tumor size and allow for sphincter preserving surgery. In this study, we hypothesized that low tumor location would be strongly associated with NACR in cT2N0M0 patients. Secondary aims were to measure the rates of abdominoperineal resection (APR) and 30d postoperative complications.
Methods: Retrospective data from NSQIP (2017–2022) included cT2N0M0 rectal cancer patients. Analyses included bivariate tests and multivariable logistic regression (1) to identify factors associated with NACR, and (2) to test whether NACR was associated with 30d postoperative complications. Analyses were done with patients subdivided based on tumor location (upper, middle, and low), examining rates of APR and pathologic complete response (pCR).
Results: 872 patients with clinical T2N0M0 rectal cancer were included in the analysis (34.4% NACR, 65.6% UFS). In bivariate analyses, in comparison to UFS, NACR had higher frequencies of patients with low (62.6% vs 50.7%, p<0.001) tumor location, and younger age (59.7% vs 44.5%, p<0.001). These associations remained robust in MVR, with results shown in Table 1. There were no significant differences in rates of overall postoperative complications on bivariate analysis (20.0% vs 18.7%, p = 0.652) or MVR (OR: 0.86, CI 0.54-1.38, p= 0.524). For sphincter preservation, rates of APR were higher in patients with NACR compared to those with UFS (61.0% vs. 50.3 %, p= 0.003). When APR rates were analyzed in subgroups based on tumor location, there were no differences for low (70.1% vs. 71.4%, p= 0.830) or upper (30.0% vs 31.0%, p= 1.000) rectal tumors, but patients with mid rectal tumors who received NACR had higher rates of APR compared to UFS (47.6% vs 30.3%, p= 0.008). Rates of pCR were significantly higher in the NACR group overall (22.6% vs. 5.3%, p<0.001) and for each tumor location subgroup (upper 35.0% vs. 6.0%, p= 0.002; mid 20.2% vs. 2.9%, p<0.001; low 20.3% vs. 5.3%, p<0.001) (Table 2).
Conclusions: The strong associations between off-guideline NACR and low-mid rectal tumors suggest that NACR is being administered to allow for sphincter-preserving surgery. In contrast to expectations, we found no improvement in sphincter preservation in the NACR groups. Rather, NACR was associated with a higher APR rate overall and in mid-rectal patients, and an equal rate in low and upper tumors. While NACR did lead to higher rates of pCR, the lack of association with increased sphincter preservation calls into question the use of NACR in this population.
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