Pathological Complete Response After Neoadjuvant Therapy in Rectal Adenocarcinoma: a 5-Year Follow-up

Abstract

Neoadjuvant therapy is the gold standard treatment of locally advanced rectal cancer. It may induce complete sterilization of tumor cell and decreases its local recurrence rate. While 15-20% of patients were found to have pathological complete response (pCR) with combined multimodal therapy, Asian data were generally scarce. pCR rate can indicate the suitability of applying the "watch-and-wait" strategy, which advocates deferment of surgery that can alleviate surgery-associated morbidity.To determine the percentage of pCR of rectal cancer after neoadjuvant therapy. Patients diagnosed with rectal cancer underwent treatment from 2013 to 2017 were retrieved retrospectively. Demographic data, tumor localization, pre-and post-operative pathological reports, neoadjuvant therapy, and pCR status were collected from patients' records. A total of 242 out of 259 patients were treated with definitive rectal surgery. Mean age was 67.1 years old. Chinese ethnicity and male gender were predominant (n = 131, 54.1% and n = 146, 64.3% respectively). More than half (n = 124, 51.2%) had tumor located at mid or low rectum. Histologically, moderate differentiated adenocarcinoma was predominant (n = 227, 93.8%). Merely half (n = 123, 50.8%) of the patients received neoadjuvant chemoradiation therapy, but only 12 (9.8%) had a pCR. From follow-up on these 12 pCR patients, most had 2year disease-free survival but 1 (8.3%) of the pCR had distant metastasis within 1-year post-surgery. The pathological complete response rate in our center was lower than reported. Stringent patient selection with close follow-up for patients should be carried out if the "watch-and-wait" strategy is implemented in our population.

Analysis of Survival in Complete Pathological Response after Long-Course Chemoradiotherapy in Patients with Advanced Rectal Cancer

“…Early reports with 2-year and 5-year follow-up periods showed improved overall survival, decrease in the local and distant recurrence rates, and high tumor-specific survival rates in patients with cPR [20,42,43]. Recent reports with follow-up periods up to 10 years are also in favor of the absence of local recurrence and an excellent disease-free survival rate of 95% [24,34,44]. This study also reports a high survival rate for patients with TRG0 and TRG1.…”

Construction and Evaluation of Nomogram for Hematological Indicators to Predict Pathological Response after Neoadjuvant Chemoradiotherapy in Locally Advanced Rectal Cancer

“…Studies have revealed [ 13 ] that younger patients are more likely to obtain a good pathological response, consistent with our findings, because younger patients may have a stronger immune response to NCRT. However, several studies [ 14 , 15 ] revealed no significant statistical significance between age and pathological response after NCRT, and even Leow’s [ 16 ] study indicated that young age was a predictor of a lower pCR rate after NCRT because young patients may have more aggressive pathological features, associated with higher CD133 + cancer stem cell burden, thereby resulting in a poorer response to neoadjuvant therapy. Further investigation is needed on the pathological response of age to NCRT.…”

The Predictors of Complete Pathologic Response in Rectal Cancer during the Total Neoadjuvant Therapy Era: A Systematic Review

“…Zhang et al in 2020 found young patients (<40 years old) had lower pCR rates [35]. A 2021 study out of Malaysia further supported those findings, with lower pCR rates after neoadjuvant CRT [48]. However, a 2013 study from Memorial Sloan-Kettering, found similar pCR rates despite early-onset rectal cancer [49].…”

“…Other studies have shown age is not associated either positively or negatively with pCR [50]. A hypothesis for future research to explore is if younger patients have other tumor and patient characteristics, including more aggressive features, that are not responsive to treatment [48] or if younger patients are more likely to receive maximum and aggressive treatment [36] with no actual differences in pCR rate based on age.…”