Neoadjuvant Treatment for Locally Advanced Rectal Cancer: New Concepts in Clinical Trial Design

Surgical outcomes in pelvic exenteration for advanced and recurrent malignancy: a high volume single institution experience

PURPOSE

Pelvic exenteration remains the only curative treatment for advanced pelvic malignancies. However, identification of predictive factors for successful surgical outcomes is still a controversial issue at present time.

METHODS

This retrospective study included data from all adult patients with colorectal or anal advanced pelvic malignancy registered for pelvic exenteration at the Leon Berard Cancer Center (Lyon, France). The primary endpoint was the surgical outcomes and aimed to define the predictive factors for postoperative complications. Secondary endpoints included overall survival and progression free survival in patients having experienced pelvic exenteration (PE).

RESULTS

Data from 141 patients with locally advanced tumor (N = 81) or recurrent malignancies (N = 60) diagnosed between May 1994 and November 2018 were collected. The median age was 63.3 years (95%CI 20.0-92.0). Malignancies included different locations (rectal: 69.5%, left colon: 17.0% and anal: 13.5%). Posterior pelvectomy was the most frequent surgery (81.6%). The median length of hospital stay was 23.3 days (95%CI 3.0-82.0). The major complication rate at 30 days was 24.8% and 38.1% at 90 days. The median overall survival was 54.5 months (95%CI 41.5-104.1) and the median PFS was 34.5 months (95%CI 19.6-NA).

CONCLUSION

In selected patients, pelvic exenteration is associated with good surgical and survival outcomes.

Outcomes of exenteration in cT4 and fixed cT3 stage primary rectal adenocarcinoma: a subgroup analysis of consolidation chemotherapy following neoadjuvant concurrent chemoradiotherapy

PURPOSE

The aim was to evaluate the oncological outcomes and the prognostic factors following pelvic exenteration (PE) in cT4 and fixed cT3 stage primary rectal adenocarcinoma and to study the impact of consolidation chemotherapy following neoadjuvant concurrent chemoradiotherapy (NACRT).

METHODS

A retrospective analysis of a prospectively maintained database of PE from 2013 to 2018.

RESULTS

Out of 2900 colorectal resections, there were 131 pelvic exenterations that were performed, and 100 of these patients had undergone exenteration for primary rectal adenocarcinoma. Of these 100 patients, there were 81 patients who had received NACRT followed by surgery, 50 of whom who had received consolidation chemotherapy and 31 who had undergone surgery without consolidation chemotherapy. R0 resection was achieved in 90% cases. At a median follow-up of 32 months, 2-year disease free survival was 61.8% and estimated 5-year overall survival was 62%. The incidence of distant metastases was 44% vs. 19% (p = 0.023), and the 2-year distant recurrence-free survival was 58% vs. 89% (p = 0.025), respectively, in the 'consolidation chemotherapy group' and the 'no chemotherapy group'. The poorly differentiated grade of tumours, presence of lympho-vascular-invasion, consolidation chemotherapy, and disease recurrence were all found to affect the survival.

CONCLUSION

PE with R0 resection achieves excellent survival rates in cT4 and fixed cT3 stage primary rectal adenocarcinoma. The distant recurrence rate may not be altered by consolidation chemotherapy in the subset of high-risk patients. However, further research on consolidation chemotherapy following NACRT in cT4 and fixed cT3 stage primary rectal adenocarcinoma will give a definite answer in the future.

Pretreatment Albumin-to-Fibrinogen Ratio Independently Predicts Chemotherapy Response and Prognosis in Patients with Locally Advanced Rectal Cancer Undergoing Total Mesorectal Excision After Neoadjuvant Chemoradiotherapy

Background

Neoadjuvant chemoradiotherapy (nCRT) followed by surgery of total mesorectal excision (TME) is currently accepted as the standard treatment for locally advanced rectal cancer (LARC). This study aimed to investigate the potential prognostic factors, including the albumin-to-fibrinogen ratio (AFR) for LARC patients.

Methods

We retrospectively recruited LARC patients (cT3-4 and/or cN1-2) who underwent nCRT followed by TME between January 2011 and January 2015. The cut-off value of pretreatment AFR for overall survival (OS) was determined by the receiver operating characteristic (ROC) curve. The potential predictive factors for prognosis in the LARC patients were assessed by the univariate and multivariate Cox’s proportional hazard regression and Kaplan–Meier curve analyses.

Results

AFR was a significant predictor for OS with a cut-off value of 8.65 and an AUC of 0.882 (P<0.001). The pretreatment AFR level was the only independent risk factor for pathologic response to nCRT (HR: 2.44, 95% CI: 1.43–4.17, P=0.003), 5-year OS (HR: 3.31, 95% CI: 1.51–6.77, P=0.005) and disease-free survival (DFS) (HR: 2.73, 95% CI: 1.34–5.47, P=0.007) in LARC patients. A low pretreatment AFR level was significantly associated with a poor 5-year OS and DFS by the Log rank test (P=0.003 and 0.006, respectively).

Conclusion

Pretreatment AFR level was an independent prognostic factor in LARC patients undergoing TME after nCRT.

Prognostic impact of at least 12 lymph nodes after neoadjuvant therapy in rectal cancer: A meta-analysis

BACKGROUND

The number of dissected lymph nodes (LNs) in rectal cancer after neoadjuvant therapy has a controversial effect on the prognosis.

AIM

To investigate the prognostic impact of the number of LN dissected in rectal cancer patients after neoadjuvant therapy.

METHODS

We performed a systematic review and searched PubMed, Embase (Ovid), MEDLINE (Ovid), Web of Science, and Cochrane Library from January 1, 2000 until January 1, 2020. Two reviewers examined all the publications independently and extracted the relevant data. Articles were eligible for inclusion if they compared the number of LNs in rectal cancer specimens resected after neoadjuvant treatment (LNs ≥ 12 vs LNs < 12). The primary endpoints were the overall survival (OS) and disease-free survival (DFS).

RESULTS

Nine articles were included in the meta-analyses. Statistical analysis revealed a statistically significant difference in OS [hazard ratio (HR) = 0.76, 95% confidence interval (CI): 0.66-0.88, I² = 12.2%, P = 0.336], DFS (HR = 0.76, 95%CI: 0.63-0.92, I² = 68.4%, P = 0.013), and distant recurrence (DR) (HR = 0.63, 95%CI: 0.48-0.93, I² = 30.5%, P = 0.237) between the LNs ≥ 12 and LNs < 12 groups, but local recurrence (HR = 0.67, 95%CI: 0.38-1.16, I² = 0%, P = 0.348) showed no statistical difference. Moreover, subgroup analysis of LN negative patients revealed a statistically significant difference in DFS (HR = 0.67, 95%CI: 0.52-0.88, I² = 0%, P = 0.565) between the LNs ≥ 12 and LNs < 12 groups.

CONCLUSION

Although neoadjuvant therapy reduces LN production in rectal cancer, our data indicate that dissecting at least 12 LNs after neoadjuvant therapy may improve the patients’ OS, DFS, and DR.

Predicting prognosis according to preoperative chemotherapy response in patients with locally advanced lower rectal cancer

BACKGROUND

Neoadjuvant chemoradiotherapy is regarded as the standard of treatment for locally advanced lower rectal cancer, although some of these cases are systemic, and distant control may be inadequate. Neoadjuvant chemotherapy could compensate for such shortcomings, potentially yielding better survival outcomes. We aimed to stratify patients into prognostic groups on the basis of preoperative factors, including response to neoadjuvant chemotherapy.

METHODS

We retrospectively analyzed patients with locally advanced lower rectal adenocarcinoma (clinical stage II/III with high-risk features of distant metastasis) who were treated with neoadjuvant chemotherapy (without radiotherapy) followed by curative resection between 2010 and 2017. Reduction in tumor volume (before vs. after neoadjuvant chemotherapy) was measured using magnetic resonance imaging, and a reduction above 60% was defined as a good response. Recurrence and overall survival were evaluated.

RESULTS

The cohort comprised 102 patients. Good response to neoadjuvant chemotherapy was associated with better 5-year recurrence-free survival (good responders: 81.1%, poor responders: 49.0%; p = 0.001) and 5-year overall survival (good responders: 94.9%, poor responders: 80.6%; p = 0.06). In a multivariate analysis, extramural venous invasion on magnetic resonance imaging after neoadjuvant chemotherapy and a tumor volume reduction rate < 60 were found to be significantly and independently associated with worse recurrence-free survival (hazard ratio: 2.74, 95% confidence interval: 1.36-5.50, p = 0.005 and hazard ratio: 3.48, 95% confidence interval: 1.57-7.72, p = 0.002, respectively). Good responders without extramural venous invasion had the best 5-year recurrence-free and overall survival (89.0 and 93.8%, respectively). Poor responders with extramural venous invasion had the worst 5-year recurrence-free and overall survival (21.4 and 50.0%, respectively).

CONCLUSIONS

Reductions in tumor volume after neoadjuvant chemotherapy were associated with a better prognosis in patients with locally advanced lower rectal cancer. Extramural venous invasion was a preoperative prognostic factor.

Surgical and Survival Outcomes Following Pelvic Exenteration for Locally Advanced Primary Rectal Cancer: Results From an International Collaboration

OBJECTIVE

The aim of the study was to analyze data from an international collaboration, and ascertain prognostic indicators that inform clinical decision-making and practices regarding the role of pelvic exenteration for locally advanced primary rectal cancer (LARC).

BACKGROUND

With improved national screening programs fewer patients present with LARC. Despite this, select cohorts of patients require pelvic exenteration. To date, the majority of outcome data are from single-center series.

METHODS

Anonymized data from 14 countries on patients who had pelvic exenteration for LARC between 2004 and 2014 were accumulated. The primary endpoint was overall survival. The impact of resection margin, nodal status, bone resection, and use of neoadjuvant therapy (before exenteration) on survival was evaluated using multivariable analysis.

RESULTS

Of 1291 patients, 778 (60.3%) were male with a median (range) age of 63 (18-90) years; 78.1% received neoadjuvant therapy. Bone resection en bloc was performed in 8.2% of patients (n = 106), and 22.6% (n = 292) had resection combined with flap reconstruction. Negative resection margin (R0 resection) was achieved in 79.9%. The 30-day postoperative mortality was 1.5%.The median overall survival following R0, R1, and R2 resection was 43, 21, and 10 months (P < 0.001) with a 3-year survival of 56.4%, 29.6%, and 8.1%, respectively (P < 0.001); 37.8% of patients experienced one or more major complication. Neoadjuvant therapy increased the risk of 30-day morbidity (P < 0.012). Multivariable analysis identified resection margin and nodal status as significant determinants of overall survival (other than advanced age).

CONCLUSIONS

Attainment of negative resection margins (R0) is the key to survival. Neoadjuvant therapy may improve survival; however, it does so at the increased risk of postoperative morbidity.

Comparing outcomes following total neoadjuvant therapy and following neoadjuvant chemoradiation therapy in patients with locally advanced rectal cancer

BACKGROUND

There is recent interest in treating locally advanced rectal cancer (LARC) patients with total neoadjuvant therapy (TNT). However, whether TNT is associated with improved overall survival (OS) remains unknown. This study compares outcomes following TNT and following neoadjuvant chemoradiation therapy (nCRT) in patients with LARC, clinically defined cT3/4 or node positive disease, using the National Cancer Database.

METHODS

LARC patients diagnosed between 2004-2015 were included. TNT was defined as multi-agent chemotherapy given at least 2 months before RT followed by pre-operative chemoradiation therapy and definitive surgery without adjuvant chemotherapy. nCRT was defined as pre-operative RT and chemotherapy started within 2 weeks from each other followed by definitive surgery with or without adjuvant chemotherapy. Kaplan-Meier curve with logrank test and multivariable Cox proportional hazards regression modelling were used to analyse the primary endpoint of overall survival (OS). Multivariable logistic regression modelling was used for secondary outcomes to determine if TNT is associated with pathological complete response (pCR), defined as ypT0N0, and negative circumferential resection margin (CRM).

FINDINGS

Data from 372 TNT patients and 707 nCRT patients were analysed after a 2:1 propensity matching with replacement. Kaplan-Meier curve showed that OS with TNT was comparable to that with nCRT (p = 0•16). The 5-year OS rates for TNT and nCRT were 73•6% vs. 78•5% (p = 0•20). Multivariable Cox proportional hazards regression modelling confirmed no difference in OS between TNT and nCRT (HR = 1•21, p = 0•25). With TNT, 16•9% patients achieved pCR, whereas 13•1% patients achieved pCR with nCRT (p = 0•12). TNT was not found to be significantly associated with pCR (OR = 1•36, p = 0•13) or negative CRM (OR = 1•77, p = 0•19) in multivariable logistic regression modelling.

INTERPRETATION

With results from current clinical trials pending, our data suggested that TNT and nCRT resulted in similar survival, while TNT led to higher pCR and CRM negative rate, albeit not statistically significant.

Cyclin-dependent kinase 1 targeting improves sensitivity to radiation in BRAF V600E colorectal carcinoma cells

OBJECTIVES

Preoperative chemoradiation is currently the standard of care in locally advanced rectal carcinoma, even though a subset of rectal tumors does not achieve major clinically meaningful responses upon neoadjuvant chemoradiation. At present, no molecular biomarkers are available to predict response to neoadjuvant chemoradiation and select resistant tumors willing more intense therapeutic strategies. Thus, BRAF mutational status was investigated for its role in favoring resistance to radiation in colorectal carcinoma cell lines and cyclin-dependent kinase 1 as a target to improve radiosensitivity in BRAF V600E colorectal tumor cells.

METHODS

Colony-forming assay and apoptotic rates were evaluated to compare the sensitivity of different colon carcinoma cell lines to ionizing radiation and their radiosensitivity upon exposure to BRAF and/or cyclin-dependent kinase 1 inhibitory/silencing strategies. Cyclin-dependent kinase 1 expression/subcellular distribution was studied by immunoblot analysis.

RESULTS

Colon carcinoma BRAF V600E HT29 cells exhibited poor response to radiation compared to BRAF wild-type COLO320 and HCT116 cells. Interestingly, neither radiosensitizing doses of 5-fluoruracil nor BRAF inhibition/silencing significantly improved radiosensitivity in HT29 cells. Of note, poor response to radiation correlated with upregulation/relocation of cyclin-dependent kinase 1 in mitochondria. Consistently, cyclin-dependent kinase 1 inhibition/silencing as well as its targeting, through inhibition of HSP90 quality control pathway, significantly inhibited the clonogenic ability and increased apoptotic rates in HT29 cells upon exposure to radiation.

CONCLUSION

These data suggest that BRAF V600E colorectal carcinoma cells are poorly responsive to radiation, and cyclin-dependent kinase 1 represents a target to improve radiosensitivity in BRAF V600E colorectal tumor cells.

Prognostic significance of neoadjuvant rectal score in locally advanced rectal cancer after neoadjuvant chemoradiotherapy and construction of a prediction model

AIM

To evaluate the prognostic significance of neoadjuvant rectal (NAR) score after neoadjuvant chemoradiotherapy (nCRT) for locally advanced rectal cancer (LARC), and to develop a nomogram predicting disease-free survival (DFS).

METHOD

A total of 522 LARC patients undergoing nCRT and surgery were included. NAR scores were calculated using the equation [5pN-3(cT-pT) + 12]^2/9.61, and classified as low (<8), intermediate (8-16), and high (>16). Clinicopathological and survival outcomes were compared. Cox regression analysis was performed to identify risk factors of DFS. A predicting nomogram was developed and validated internally.

RESULTS

For NAR score classification, 193 (37.0%) were low, 183 (35.0%) were intermediate, and 146 (28.0%) were high. Higher NAR score was associated with fewer pCR, lower tumor regression grade (TRG), and higher ypTNM stage. A total of 5-year DFS for low, intermediate, and high NAR groups was 85.6%, 71.9%, and 47.2%, respectively (P < 0.001). NAR score (HR = 2.488, P = 0.002), TRG (HR = 2.811, P = 0.047), CRM involvement (HR = 2.703, P = 0.002), and IMA nodal metastasis (HR = 2.441, P = 0.001) were independent prognostic factors of DFS. A predicting nomogram was developed with C-index of 0.701.

CONCLUSION

NAR score could help in predicting DFS after nCRT. A nomogram was developed to identify subpopulations with aggressive tumors during clinical decision-making.