Validation of the Neoadjuvant Rectal Cancer (NAR) Score for Prognostication Following Total Neoadjuvant Therapy (TNT) for Locally Advanced Rectal Cancer

PURPOSE

The neoadjuvant rectal cancer (NAR) score is a prognostic tool for locally advanced rectal cancer (LARC) treated with total neoadjuvant therapy (TNT). It has been previously validated as an endpoint that predicts survival more accurately than pathologic complete response (pCR) and is the primary endpoint of the ongoing NRG-GI002 Phase II trial. Using the National Cancer Database (NCDB), we aimed to validate the NAR score's ability to predict survival in a large hospital-based dataset.

METHODS

We queried the NCDB to identify locally advanced rectal cancer patients from 2004 to 2015 that received TNT followed by surgical resection. Overall survival (OS) was calculated using Kaplan-Meier curves evaluating NAR score and pCR separately. A multivariable Cox proportional hazards model was used to identify factors associated with survival. Multivariate regression was used to evaluate characteristics associated with a favorable (< 14.98) NAR score.

RESULTS

From > 264,000 patients diagnosed with rectal adenocarcinoma in the NCDB, our final cohort yielded 209 patients with a median age of 62 years. Factors associated with worse survival included age > 62 years old (p = 0.04), lower income (p = 0.03), and unfavorable (≥ 14.98) NAR score (p = 0.04). On multivariate regression, tumors with perineural invasion and a higher comorbidity score (> 1) were less likely to have a favorable NAR response (p = 0.01 and p = 0.01). pCR was not associated with improved survival (p = 0.09).

CONCLUSIONS

Our study validates the NAR score as a prognostic tool in patients receiving TNT for LARC. Tumors with perineural invasion and patients with a higher comorbidity score had worse NAR scores.

A phase II randomized double blinded trial evaluating the efficacy of curcumin with pre-operative chemoradiation for rectal cancer

Background

In vivo studies demonstrate that curcumin increases radioresponse of colorectal cancers. To demonstrate efficacy in humans, we performed a randomized double-blind study of locally advanced rectal cancer (LARC) patients receiving pre-operative chemoradiation therapy (CRT) ± curcumin. We used pathologic complete response (pCR) rate as a surrogate for clinical outcome.

Methods

From 2008-2010, LARC patients were randomized to placebo/curcumin in a 1:2 ratio. Patients received CRT [50.4 gray in 28 fractions; capecitabine (825 mg/m² twice daily)] followed by surgery. Curcumin (4 grams orally, twice daily) or placebo was given throughout CRT and 6 weeks afterward. Toxicity was monitored weekly. Blood samples taken pre- and 1-hour post-ingestion and tissue biopsies (both collected at CRT week 2) were analyzed for pharmacokinetics. The primary outcome was surgical pCR rate.

Results

Of 22 enrolled patients, 15 received curcumin. Median age was 61 years and the majority were male (n=13; 59%). The median serum curcumin concentrations before (3.04 ng/mL; range, 1.24-18.88 ng/mL) and 1 hour after (3.32 ng/mL; range, 0.84-5.36 ng/mL) curcumin intake did not differ significantly (P=0.33). Serum curcumin concentrations both increased and decreased 1-hour post-administration (range as percentage of baseline: 8.8-258.1%). Twelve curcumin patient tissue biopsies had median curcumin concentration of 33.7 ng/mg tissue (range, 0.1-4,765.7 ng/mg). Two placebo and 1 curcumin patient achieved pCRs (P=0.18). One grade 3 toxicity (infection) was experienced.

Conclusions

The addition of curcumin to CRT did not increase pCR rates for LARC patients. The unpredictable bioavailability of curcumin contributes to continued uncertainties regarding curcumin efficacy.

Trial Registration

ClinicalTrials.gov identifier: NCT00745134.

Development and external validation of prognostic nomograms for liver disease-free and overall survival in locally advanced rectal cancer with neoadjuvant therapy: a post cohort study based on the FOWARC trial

Background

There is still a lack of nomograms that can accurately predict liver metastasis and poor prognosis after neoadjuvant therapy for locally advanced rectal cancer (LARC). Effective nomograms may help clinicians better identify LARC patients with potential high-risk risks, so as to carry out more targeted monitoring, treatment and follow-up.

Methods

The nomograms were based on the FOWARC trial (NCT01211210), which included 302 LARC patients who underwent neoadjuvant treatment before surgery at the Sixth Affiliated Hospital of Sun Yat-sen University from 2011 to 2014. The predictive accuracy and discriminative ability of the nomograms were determined by the concordance index (C-index) and calibration curve. The results were validated using bootstrap resampling and a prospective study on 100 patients in 2017.

Results

The 3-year liver disease-free survival (LDFS) rate after neoadjuvant treatment for LARC was 91.65% (training cohort 92.22%, validation cohort 90.01%). Factors associated with LDFS were hepatitis B virus (HBV) infection, anemia, lymph node number, postoperative T stage and tumor nodule, which were all included in the nomogram for LDFS. The C-indies of the nomogram for LDFS were 0.828 and 0.845 in the training and validation cohorts. The 3-year overall survival (OS) rate was 94.14% (training cohort 94.13%, validation cohort 94.05%). Factors in the nomogram for OS were mesorectal fascia involvement (MRF), postoperative N stage, pathological differentiation, tumor nodule and neural invasion. The C-indies of the nomogram for predicting OS were 0.73 and 0.774 in the training and validation cohorts. The calibration curve for the survival probability showed good agreement between the nomogram predictions and the actual observations.

Conclusions

The nomograms established in this study can effectively predict LDFS and has good clinical application potential for OS in LARC patients treated with neoadjuvant therapy.

Total Neoadjuvant Therapy (TNT) versus Standard Neoadjuvant Chemoradiotherapy for Locally Advanced Rectal Cancer: A Systematic Review and Meta-Analysis

BACKGROUND

Total neoadjuvant therapy (TNT) is a novel approach for locally advanced rectal cancer (LARC), which attempts to deliver both systemic chemotherapy and neoadjuvant chemoradiotherapy prior to surgery. However, its efficacy and safety remain controversial in randomized controlled trials (RCTs). We conducted this meta-analysis to assess such concerns.

MATERIALS AND METHODS

Head-to-head phase II/III RCTs were searched in Embase, PubMed, Web of Science, and the Cochrane Library, as well as other sources. The primary endpoint was pathologic complete response (pCR). Secondary endpoints were disease-free survival (DFS), overall survival (OS), local recurrence-free survival, distant metastasis-free survival, and the R0 resection rate.

RESULTS

Eight phase II/III RCTs involving 2,196 patients with LARC were assessed. The primary analysis demonstrated a statistically significant improvement in the pCR rate for TNT treatment (odds ratio, 1.77; 95% confidence interval [CI], 1.28-2.45; p = .0005). TNT treatment also showed improvements in DFS and OS outcomes compared with standard chemoradiotherapy (hazard ratio [HR], 0.83; 95% CI, 0.72-0.96; p = .03 and HR, 0.88; 95% CI, 0.74-1.05; p = .15). In addition, TNT treatment showed significant efficacy in reducing the risk of distant metastasis (HR, 0.81; 95% CI, 0.68-0.95; p = .012).

CONCLUSION

The overall pCR rate may be improved with TNT compared with standard treatment. The TNT strategy may also improve DFS and OS and reduce the risk of distant metastasis.

IMPLICATIONS FOR PRACTICE

Locally advanced rectal cancer (LARC) is a relatively common disease, with a poor prognosis because of its high metastatic potential. The role of total neoadjuvant therapy (TNT) has always been controversial. This meta-analysis found that TNT in LARC is associated with a significant improvement in overall pathologic complete response rate, disease-free survival, overall survival, and distant metastasis-free survival compared with standard treatment. TNT is a promising strategy for LARC, especially for patients who have little desire for surgery.

Preliminary results of simultaneous integrated boost intensity-modulated radiation therapy based neoadjuvant chemoradiotherapy on locally advanced rectal cancer with clinically suspected positive lateral pelvic lymph nodes

Background

Lateral pelvic lymph node (LPLN) is approximately 11–14% and always associated with poorer prognosis. This study investigated the efficacy and safety of simultaneous integrated boost intensity-modulated radiation therapy (SIB-IMRT) based on neoadjuvant chemoradiotherapy (NCRT) on locally advanced rectal cancer (LARC) patients with clinically suspected positive LPLNs.

Methods

We retrospectively screened distal LARC patients with NCRT in our center from May 2016 and June 2019. The diagnostic criteria of positive LPLN were nodes of over 7 mm in short axis and irregular border or mixed-signal intensity. All patients with clinically suspected positive LPLN received 56–60 Gy SIB-IMRT in the LPLN area. Concurrent chemotherapy regimens were capecitabine as monotherapy treatment or in combination with oxaliplatin. The toxicities, local-regional recurrence (LRR), and disease-free survival (DFS) were investigated.

Results

Fifty-two eligible patients with clinically suspected positive LPLN were screened and analyzed. The median distance from the distal tumor to the anal verge was 4 cm (range, 0–8 cm), while magnetic resonance imaging (MRI) analysis revealed the median short diameter of the pelvic LPLN to be 8 mm (range, 7–20 mm). There were 28 (53.8%) mesorectal fascia (MRF) positive and 22 (42.3%) extramural venous invasion (EMVI) positive patients. A radiotherapy dose of 41.8 Gy was administered to the pelvic area, while the LPLN received a median SIB dose of 60.0 Gy (range, 56–60 Gy) across 22 fractions. Synchronous capecitabine with or without oxaliplatin was administered during radiotherapy. In summary, 15 (28.8%) patients displayed grade 2–3 radiation-related toxicity, 8 (15.4%) patients underwent additional LPLN dissection, and positive nodes (26 nodes in total) were not observed. One patient suffered a LLR in the presacral region. The median follow-up duration was 21.2 months (range, 4.7–45.0 months), while the duration of 1- and 2-year DFS were 89.9% and 74.6%, respectively. Patients did not display LPLN recurrence.

Conclusions

The safety and efficacy of SIB-IMRT on clinically suspected positive LPLN of LARC patients were deemed acceptable. Patients did not exhibit in-field LPLN recurrence after NCRT combined with single total mesorectal excision (TME).

Accurate nomograms with excellent clinical value for locally advanced rectal cancer

Background

Rectal cancer accounts for approximately 30–50% of colorectal cancer. Despite its widespread use and convenience, the American Joint Committee on Cancer (AJCC) staging system for predicting survival is prone to inaccuracy, even including a survival paradox for locally advanced rectal cancer (LARC). An accurate risk stratification of LARC is essential for proper treatment selection and prognostic evaluation. Therefore, we aimed to create prognostic nomograms for LARC capable of assessing overall survival (OS) and cancer-specific survival (CSS) precisely and intuitively.

Methods

The Surveillance, Epidemiology, and End Results (SEER) database was accessed. All of the significant variables in the multivariate analysis were integrated to build the nomograms.

Results

Data for a total of 23,055 patients with LARC were collected from the SEER database in this study. Based on the multivariate Cox regression analysis, both OS and CSS were significantly associated with 13 variables: age, marital status, race, pathological grade, histological type, T stage, N stage, surgery, radiotherapy, chemotherapy, regional nodes examined (RNE), tumor size, and carcinoembryonic antigen (CEA). These were included in the construction of nomograms for OS and CSS. Time-dependent receiver operating characteristic (ROC) curves, decision curve analysis (DCA), concordance index, and calibration curves demonstrated the discriminative superiority of the nomograms.

Conclusions

The nomograms, which effectively solve the issue of the survival paradox in the AJCC staging system regarding LARC, may act as excellent tools for integrating clinical characteristics and to guiding therapeutic choices for LARC patients.

Good response to neoadjuvant chemoradiotherapy predicts good oncological outcome in locally advanced rectal cancer

BACKGROUND

After pre-operative concurrent long course chemoradiotherapy (CRT), pathologic complete response (pCR) has been reported with better oncologic outcomes in many articles, whether a moderate response (TRG1) can translate into good clinical outcome remains uncertain.

METHODS

A total of 132 locally advanced rectal cancer patients with neoadjuvant chemoradiotherapy followed by radical surgery were recruited. Their clinicopathologic characteristics and clinical records were retrospectively reviewed. The association between clinicopathologic parameters and pathological response was conducted, and the multivariable analysis of the association between pathologic response and survival was performed.

RESULTS

With a median follow-up of 21.5 months, gender was the only factor associated with pCR (TRG0), while dual-agent chemotherapy regimen was linked with a lower likelihood of good response (TRG0-1). Good response (TGR0-1) remained significant associated with overall survival (OS) and disease-free survival (DFS) after multivariate adjustment. TRG1 was linked with better DFS compared with TRG2-3.

CONCLUSIONS

Patients with post-CRT good response (TRG0-1) demonstrate an excellent local and remote control, especially with those non-pCR patients (TRG1) getting better outcomes.

A comparison of fitting algorithms for diffusion-weighted MRI data analysis using an intravoxel incoherent motion model

OBJECT

The objective of this study is to propose a modified VARiable PROjection (VARPRO) algorithm specifically tailored for fitting the intravoxel incoherent motion (IVIM) model to diffusion-weighted magnetic resonance imaging (DW-MRI) data from locally advanced rectal cancer (LARC).

MATERIALS AND METHODS

The proposed algorithm is compared with classical non-linear least squares (NLLS) analysis using the Levenberg-Marquardt (LM) algorithm and with two recently proposed algorithms for 'segmented' analysis. These latter two comprise two consecutive steps: first, a subset of parameters is estimated using a portion of data; second, the remaining parameters are estimated using the whole data and the previous estimates. The comparison between the algorithms was based on the [Formula: see text] goodness-of-fit measure: performance analysis was carried out on real data obtained by DW-MRI on 40 LARC patients.

RESULTS

The performance of the proposed algorithm was higher than that of LM in 64 % of cases; 'segmented' methods were poorer than our algorithm in 100 % of cases.

CONCLUSION

The proposed modified VARPRO algorithm can lead to better fit of the IVIM model to LARC DW-MRI data compared to other techniques.

The best timing for administering systemic chemotherapy in patients with locally advanced rectal cancer

Over the past several decades, outcomes for patients with rectal cancer have improved considerably. However, several questions have emerged as survival times have lengthened and quality of life has improved for these patients. Currently patients with locally advanced rectal cancer (LARC) are often recommended multimodality therapy with fluoropyrimidine-based chemotherapy (CT) and radiation followed by total mesorectal excision (TME), with consideration given to FOLFOX before chemoradiotherapy (CRT). Recently, Garcia-Aguilar and colleagues reported in Lancet Oncology that the addition of mFOLFOX6 administered between CRT and surgery affected the number of patients achieving pathologic complete response (pathCR), which is of great interest from the standpoint of pursuit of optimal timing of systemic CT delivery. This was a multicenter phase II study consisting of 4 sequential treatment groups of patients with LARC, and they reported that patients given higher number CT cycles between CRT and surgery achieved higher rates of pathCR than those given standard treatment. There was no association between response improvement and tumor progression, increased technical difficulty, or surgical complications. Ongoing phase III clinical trial further assessing this strategy might result in a paradigm shift.