Difference in Tumor Area as a Predictor of a Pathological Complete Response for Patients With Locally Advanced Rectal Cancer

Abstract

PurposeThis study was conducted to discover the clinical factors that can predict pathologically complete remission (pCR) after neoadjuvant chemoradiotherapy (CRT), so that those factors may help in deciding on a treatment program for patients with locally advanced rectal cancer.MethodsA total of 137 patients with locally advanced rectal cancer were retrospectively enrolled in this study, and data were collected retrospectively. The patients had undergone a total mesorectal excision after neoadjuvant CRT. Histologic response was categorized as pCR vs. non-pCR. The tumor area was defined as (tumor length) × (maximum tumor depth). The difference in tumor area was defined as pre-CRT tumor area – post-CRT tumor area. Univariate and multivariate logistic regression analyses were conducted to find the factors affecting pCR. A P-value < 0.05 was considered significant.ResultsTwenty-three patients (16.8%) achieved pCR. On the univariate analysis, endoscopic tumor circumferential rate <50%, low pre-CRT T & N stage, low post-CRT T & N stage, small pretreatment tumor area, and large difference in tumor area before and after neoadjuvant CRT were predictive factors of pCR. A multivariate analysis found that only the difference in tumor area before and after neoadjuvant CRT was an independent predictor of pCR (P < 0.001).ConclusionThe difference in tumor area, as determined using radiologic tools, before and after neoadjuvant CRT may be important predictor of pCR. This clinical factor may help surgeons to determine which patients who received neoadjuvant CRT for locally advanced rectal cancer should undergo surgery.

Predicting stage ypT0–1N0 for nonradical management in patients with middle or low rectal cancer who undergo neoadjuvant chemoradiotherapy: a retrospective cohort study

“…They suggested that a combination of clinical, laboratory, and metabolic data would best predict pCR. However, other studies reported DRE and endoscopy as poor methods for distinguishing between postradiation fibrosis and residual cancer [ 28 29 30 ]. Notably, all these studies assessed tumors after CCRT to determine whether pCR was achieved but did not attempt to predict tumor response based on pretreatment gross morphology.…”

Radiotherapy after local excision of rectal cancer may offer reduced local recurrence rates

“…The rationale for adjuvant therapy is supported by evidence that radiotherapy is more efficacious in patients with a small volume of cancer . This is demonstrated by high levels of complete pathological response rates in T2 tumours of 40%–50% compared to 12%–15% in more advanced T3–T4 cancers , although the aggressiveness of the radiotherapy may also play a role.…”