Abstract
We aimed to identify predictors of a pathological complete response (pCR) in patients with locally advanced rectal cancer (LARC) following a multimodality therapy. We retrospectively reviewed 236 patients with LARC treated with neoadjuvant chemoradiotherapy (CRT) followed by radical resection from January 2011 to December 2017. Patients were administered CRT, which comprised radiotherapy and chemotherapy with an oxaliplatin plus 5-fluorouracil- or fluoropyrimidine-based regimen. Clinical factors were correlated with treatment response. The multivariate logistic regression revealed that a negative nodal stage (odds ratio (OR) = 3.2, P=0.0135), a high hemoglobin level (>10 g/dL) during neoadjuvant CRT (OR = 3.067, P=0.0125), an oxaliplatin-containing neoadjuvant CRT (OR = 5.385, P=0.0044), a long interval (>8 weeks) between radiotherapy and surgery (OR = 1.135, P=0.0469), and a post-CRT CEA ≤2 ng/mL (OR = 2.891, P=0.0233) were the independent predictors of increased pCR rates. The prediction nomogram was developed according to the above independent variables. The concordance index was 0.74, and the calibration curve showed good agreement. In summary, negative nodal stages, high hemoglobin levels during treatment, oxaliplatin-containing neoadjuvant therapy, a long radiotherapy-surgery interval (>8 weeks), and post-CRT CEA levels ≤2 ng/mL were favorable predictors of a pCR. This prediction nomogram might be crucial for patients with LARC undergoing a multimodality therapy.
Highlights
For locally advanced rectal cancer (LARC), neoadjuvant chemoradiotherapy (CRT) has been the standard treatment because it provides high local control, low treatment toxicity, high rates of sphincter preservation, and improved diseasefree survival (DFS) [1,2,3]
Forty-five patients were treated with three-dimensional conformal radiation therapy, and 191 patients were treated with intensity-modulated radiation therapy. e median number of cycles of chemotherapy was seven, with 80 patients (33.9%) receiving at least seven cycles of chemotherapy. e median number of post-CRT carcinoembryonic antigen (CEA) was 2.2 ng/mL, ranging from 0.48 to 197.5 ng/mL. erefore, 2 ng/mL was selected as the cutoff value for post-CRT CEA level
We found that patients with a clinically negative nodal disease, without anemia during treatment, with a long interval (>8 weeks) between radiotherapy and surgery, with post-CRT CEA levels ≤2 ng/mL, and receiving a FOLFOX-based regimen were more likely to achieve a pathological complete response (pCR) to CRT
Summary
For locally advanced rectal cancer (LARC), neoadjuvant chemoradiotherapy (CRT) has been the standard treatment because it provides high local control, low treatment toxicity, high rates of sphincter preservation, and improved diseasefree survival (DFS) [1,2,3]. Some clinical parameters and molecular biomarkers have been reported to be predictors of a pCR to neoadjuvant CRT for patients with LARC [9,10,11]. Several clinical factors, such as pretreatment T or N stage, serum carcinoembryonic antigen (CEA), chemotherapy regimen, and radiation dose, have been associated with a pCR [5,12,13,14,15,16]. Few studies have investigated the effect of treatment-related hematologic toxicity on a pCR
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