Debating Pros and Cons of Total Neoadjuvant Therapy in Rectal Cancer

A randomized phase 3 trial of total neoadjuvant therapy (induction chemotherapy, neoadjuvant chemoradiation, neoadjuvant chemotherapy, and surgery) vs. standard long-term chemoradiation therapy (neoadjuvant chemoradiation, surgery, and adjuvant chemotherapy) in locally advanced rectal cancer

Purpose

The management of rectal adenocarcinoma has evolved during the last decade, shifting from a conventional neoadjuvant chemoradiotherapy, surgery, and adjuvant chemotherapy in all cases to a total neoadjuvant approach, especially in locally advanced tumors when a sphincter-sparing surgery has been planned. However, the exact indications and the neoadjuvant regimen with the highest response remain unresolved. We aimed to assess whether administering neoadjuvant chemotherapy before and after preoperative chemoradiotherapy could increase the pathological complete response (pCR) rates.

Methods

We conducted a phase 3, multicenter, randomized trial at four hospitals in Iran. Adult patients with a newly diagnosed, biopsy-proven, locally advanced non-metastatic rectal adenocarcinoma with an ECOG performance status of 0-2 were randomly assigned (2:2) to either the total neoadjuvant treatment (TNT) or the standard-of-care groups using a block randomized design. Investigators and participants were not masked to treatment allocation and groups. The TNT group received neoadjuvant chemotherapy with FOLFOX6 (intravenous 85 mg/m2 oxaliplatin and 400 mg/m2 leucovorin, followed by intravenous 400 mg/m2 fluorouracil bolus and then continuous infusion at a dose of 2,400 mg/m2 over 46 h every 14 days for four cycles before and four cycles after chemoradiotherapy), chemoradiotherapy (50.4 Gy during 28 fractions and 800 mg/m2 concurrent oral capecitabine twice daily 5 days per week), and total mesorectal excision. The standard-of-care group received neoadjuvant chemoradiotherapy, total mesorectal excision, and adjuvant chemotherapy (eight cycles). The primary endpoint was the pathological complete response. Safety analyses were conducted on treated patients.

Results

Overall, 25 and 27 patients were enrolled in the TNT and standard-of-care groups, respectively. Both groups were similar in terms of gender, age, and tumor differentiation. The tumors in the standard-of-care group were significantly located closer to the anal verge compared with those in the TNT group (9.4 ± 3.7 cm in TNT vs. 6.8 ± 4 cm in standard, p = 0.02). A pCR was reached in 48% (12/25) and 25.9% (7/27) of patients in the TNT and standard-of-care groups, respectively (p = 0.4). The R0 resection rates were identical between the two groups (92% vs. 88.9%, p = 0.3). Moreover, the toxicity rates were similar between the two groups.

Conclusion

Our results showed that TNT is a safe and feasible treatment approach in patients with rectal cancer and may improve the overall pCR rate compared with standard treatment.

Clinical trial registration

https://irct.behdasht.gov.ir/trial/65666, identifier IRCT20220723055527N1.

Optimal Sequence for Total Neoadjuvant Therapy in Locally Advanced Rectal Cancer: An Evidence-Based Review

INTRODUCTION

Historically, multimodal therapeutic strategies involving preoperative chemoradiotherapy (CRT), surgery, and adjuvant chemotherapy (CT) have been employed to treat locally advanced rectal cancer (LARC). Total Neoadjuvant Therapy (TNT) is showing promise in improving outcomes. Despite its benefits, the optimal sequencing within TNT-whether induction chemotherapy should precede or follow chemoradiotherapy-remains a critical question. This study endeavors to explore the effects of different TNT sequencing strategies on patient outcomes, including tumor downstaging, pathological response, organ preservation, and the balance between efficacy and tolerability.

METHODS

Our methodology entailed a comprehensive literature review conducted on Medline, focusing on recent research, including retrospective studies, systematic reviews, and clinical trials. The review emphasized the comparison of induction chemotherapy versus consolidation chemotherapy within TNT regimens, assessing outcomes such as pathological response, organ preservation rates, and adverse effects. To ensure the selection of appropriate and high-quality studies, specific inclusion and exclusion criteria were applied.

RESULTS

The analysis revealed that induction chemotherapy might lead to decreased adherence to subsequent chemoradiotherapy while offering an early intervention against micrometastasis and potentially improving overall chemotherapy compliance. Conversely, consolidation chemotherapy has been associated with higher pathological complete response (pCR) rates and improved tolerability, indicating its potential for patients requiring local symptom relief or those eligible for a nonoperative management approach. Comparative studies like CAO/ARO/AIO-12 and the OPRA trials have significantly contributed to our understanding, suggesting that while both strategies have distinct advantages, the choice between induction and consolidation chemotherapy should be tailored based on individual patient profiles and tumor characteristics.

CONCLUSION

This narrative review underscores the importance of a nuanced approach to TNT sequencing in locally advanced rectal cancer, highlighting the need for further research to refine treatment strategies.

Is There any Benefit of Addition of Neo-Adjuvant Chemotherapy (FOLFOX4) to Standard Preoperative Treatment of Rectal Cancer? A Randomized Clinical Trial

BACKGROUND

Total neoadjuvant therapy (TNT) before surgical intervention represents a unique therapeutic approach for the management of locally advanced rectal cancer (LARC) and has witnessed a notable rise in utilization within recent years. However, the efficacy and safety of this treatment remain subjects of ongoing debate and investigation. This randomized controlled trial aimed to evaluate the potential impact of administering induction chemotherapy (IC) before the conventional neoadjuvant concomitant chemoradiotherapy (nCRT) in LARC patients.

MATERIALS & METHODS

patients with resectable stage II-III LARC were randomly allocated to receive either biweekly 6 cycles of FOLFOX4 regimen as IC followed by CRT and total mesorectal excision (TME) (experimental group) or nCRT followed by TME (control group). The primary endpoint was the rate of pathological complete response (pCR). The secondary endpoints encompassed the evaluation of treatment-related adverse events as well as the assessment of survival outcomes.

RESULTS

67 patients were enrolled in this study (32 in the experimental group and 35 in the control group). The median age of the patients was 45 years. Stage IIIB was observed in 46.3% of the patients. The patients who underwent induction chemotherapy demonstrated a notably higher rate of achieving pCR in comparison to the control group (28.1% vs 8.6%; P=0.001). There were no statistically significant differences observed in terms of their toxicity profile and survival outcomes.

CONCLUSIONS

Implementation of induction chemotherapy utilizing the FOLFOX4 regimen has demonstrated a notable enhancement in the rate of pathological complete response. However, this improvement does not appear to translate into significant advancements in overall survival outcomes.

Applying the fragility index to randomized controlled trials evaluating total neoadjuvant therapy for rectal cancer: A methodological survey

BACKGROUND

Recently, there has been significant interest in, and adoption of, total neoadjuvant therapy (TNT) for locally advanced rectal cancer (LARC). We designed the present study to assess the robustness of the randomized controlled trials (RCTs) evaluating contemporary TNTs for LARC using the fragility index (FI).

MATERIALS AND METHODS

Relevant articles were identified through a review article by Johnson et al. in the Canadian Journal of Surgery. Dichotomous outcomes within these RCTs were eligible for inclusion if the reported effect size had a p-value < 0.05. The main outcome was FI for each included outcome. Walsh et al.'s method of calculating FI was utilized. Correlations between FI and research characteristics were assessed using the Spearman's rank correlation coefficients. Risk of bias was assessed using Cochrane recommended tools.

RESULTS

Ten RCTs were identified with 25 outcomes having statistically significant differences between groups. Eleven outcomes were time-to-event outcomes, while the remainder were dichotomous outcomes. Approximately half (n = 13) were oncologic outcomes. The median FI was 2 (interquartile range [IQR] 1-16). The number of patients lost to follow-up exceeded the FI in 17 outcomes (68.0 %) and thus these results were considered "fragile". Lower FI was associated with high risk of bias (rho = -0.5594) and greater loss to follow-up (rho = -0.4394), while higher FI was associated with large study size (rho = 0.5120).

CONCLUSIONS

The robustness of outcomes from trials assessing TNT for LARC was found to be questionable. Most outcomes were fragile, as determined by the FI. This survey is limited by the number of included studies.

Total neoadjuvant therapy in rectal cancer: the evidence and expectations

Current management of locally advanced rectal cancer achieves high cure rates, distant metastatic spread being the main cause of patients' death. Total neoadjuvant therapy (TNT) employs (chemo)radiotherapy and combined chemotherapy prior to surgery to improve the treatment outcomes. TNT has been shown to reduce significantly distant metastases, increase disease-free survival by 5 - 10% in 3 years, and finally also overall survival (≈ 5% in 7 years). It proved to double the rate of pathologic complete responses, making it an attractive strategy for non-operative management to avoid permanent colostomy in patients with distal tumors. In addition, it endorses adherence to the therapy due to better tolerance and, potentially, shortens its overall duration. A number of questions related to TNT remain currently unresolved including the indications, preferred radiotherapy and chemotherapy regimens, their sequence, timing of surgery, and role of adjuvant therapy. A stratified approach may be the optimal way to go.

A contemporary assessment of total neoadjuvant therapy (TNT) protocols for locally advanced rectal cancer: adoption and expert perspectives at German Cancer Society (DKG)-certified colorectal cancer centers

PURPOSE

The treatment paradigm for locally advanced rectal cancer (LARC) is shifting toward the total neoadjuvant therapy (TNT) concept, which administered systemic chemotherapy in the neoadjuvant setting, either before or after chemoradiotherapy (CRT) or short-course radiotherapy (SCRT). First results have shown higher pathologic complete response (pCR) rates and a favorable impact on disease-free survival (DFS). Our study aimed to evaluate the current clinical practice and expert opinion regarding TNT for locally advanced rectal cancer across DKG (German Cancer Society)-certified colorectal cancer centers.

METHODS

A comprehensive online questionnaire, constituted of 14 TNT-focused queries targeting patients with locally advanced rectal cancer, was conducted among DKG-certified colorectal cancer centers registered within the database of the Addz (Arbeitsgemeinschaft Deutscher Darmzentren) between December 2022 and January 2023.

RESULTS

A significant majority (68%) indicated that they treated between 0 and 10 patients using a TNT protocol. Only a third (36%) of these centers participated in patient enrollment for a TNT study. Despite this, 84% of centers reported treating patients in a manner analogous to a TNT study, with the RAPIDO regimen being the most prevalent approach, employed by 60% of the respondents. The decision to adopt a TNT approach was primarily influenced by factors, such as the lower third of the rectum (93% of centers), cT4 stage (86% of centers), and a positive circumferential resection margin (80% of centers). Regarding concerns, 65% of the survey respondents expressed no reservations about the TNT concept, while 35% had concerns. In particular, there appears to be disagreement and uncertainty in regard to a clinical complete response and the "Watch and Wait" approach. While some centers adopt the watch-and-wait approach (42%), others only utilize it when extirpation is otherwise necessary (39%), and a portion still proceeds with surgery as initially planned (19%). The survey also addressed unmet needs, which were elaborated in the free-text responses. Overall, there was high interest in participating in planned observational studies.

CONCLUSIONS

This study presents an overview of current clinical practice and unmet needs within DKG-certified German colorectal cancer centers. It is noteworthy that total neoadjuvant therapy (TNT) is predominantly performed outside of clinical trials. Moreover, across the centers, there is significant heterogeneity in handling clinical complete response and adopting the "watch and wait" approach. Further research is needed to establish standardization in the care of locally advanced rectal cancer.

Special Issue "Current Management of Early and Advanced Rectal Cancer"

As expected, surgery for low or ultralow disease remains a challenging issue in rectal cancer treatment [...].

Personalized total neoadjuvant therapy (pTNT) for advanced rectal cancer with tailored treatment sequencing based on clinical stage at presentation

BACKGROUND

This study aimed to assess short-term outcomes of a personalized total neoadjuvant treatment (pTNT) protocol, with treatment sequencing based on clinical stage at presentation.

METHODS

A multidisciplinary pTNT protocol was implemented across two metropolitan hospitals. This consists of two-schema based on clinical stage: patients with distant failure risk were offered induction chemotherapy before chemoradiation (nCRT), and patients with locoregional failure risk received nCRT followed by consolidation chemotherapy. Patients underwent surgical resection unless a complete clinical response (cCR) was achieved, in which case non-operative management (NOM) was offered. A prospective cohort analysis of all patients with rectal cancer who underwent pTNT with curative intent between Jan 2019 and Aug 2022 was performed.

RESULTS

Of 270 patients referred with rectal cancer, 102 received pTNT with curative intent and 79 have completed their treatment thus far. Thirty-three patients (41.8%) received induction chemotherapy and 46 (58.2%) received consolidation chemotherapy per protocol. The percentage of patients with EMVI, resectable M1 disease, cT4 disease, and positive lateral lymph nodes were 54.4%, 36.7%, 27.8% and 15.2%, respectively. Overall, 32 (40.5%) patients had cCR and 4 (5.1%) pCR, and 40 (50.6%) patients had non-operative management. Grade 3 toxicity was reported in 10.1% of patients and only three patients (3.8%) experienced Grade 4 chemotherapy-related toxicity, with no treatment related mortality.

CONCLUSION

Early results with a defined two-schema pTNT protocol are encouraging and suggest that tailoring sequencing to disease risk at presentation may represent the optimal balance between local and distant disease control, as well as treatment toxicity.

Prognostic Impact of TP53 Mutations and Tumor Mutational Load in Colorectal Cancer

The DNA damage response (DDR) is critical for maintaining genome stability, and abnormal DDR—resulting from mutations in DNA damage-sensing and repair proteins—is a hallmark of cancer. Here, we aimed to investigate the predictive power of DDR gene mutations and the tumor mutational load (TML) for survival outcomes in a cohort of 22 rectal cancer patients who received pre-operative neoadjuvant therapy. Univariate analysis revealed that TML-high and TP53 mutations were significantly associated with worse overall survival (OS) with TML-high retaining significance in multivariate analyses. Kaplan–Meier survival analyses further showed TML-high was associated with worse disease-free (p = 0.036) and OS (p = 0.024) results in our patient cohort. A total of 53 somatic mutations were identified in 22 samples with eight (36%) containing mutations in DDR genes, including ATM, ATR, CHEK2, MRE11A, RAD50, NBN, ERCC2 and TP53. TP53 was the most frequently mutated gene, and TP53 mutations were significantly associated with worse OS (p = 0.023) in Kaplan–Meier survival analyses. Thus, our data indicate that TML and TP53 mutations have prognostic value for rectal cancer patients and may be important independent biomarkers for patient management. This suggests that prognostic determination for rectal cancer patients receiving pre-operative neoadjuvant therapy should include consideration of the initial TML and tumor genetic status.

Total Neoadjuvant Therapy for Rectal Cancer in the CAO/ARO/AIO-12 Randomized Phase 2 Trial: Early Surrogate Endpoints Revisited

Background: Early efficacy outcome measures in rectal cancer after total neoadjuvant treatment are increasingly investigated. We examined the prognostic role of pathological complete response (pCR), tumor regression grading (TRG) and neoadjuvant rectal (NAR) score for disease-free survival (DFS) in patients with rectal carcinoma treated within the CAO/ARO/AIO-12 randomized phase 2 trial. Methods: Distribution of pCR, TRG and NAR score was analyzed using the Pearson’s chi-squared test. Univariable analyses were performed using the log-rank test, stratified by treatment arm. Discrimination ability of non-pCR for DFS was assessed by analyzing the ROC curve as a function of time. Results: Of the 311 patients enrolled, 306 patients were evaluable (Arm A:156, Arm B:150). After a median follow-up of 43 months, the 3-year DFS was 73% in both groups (HR, 0.95, 95% CI, 0.63–1.45, p = 0.82). pCR tended to be higher in Arm B (17% vs. 25%, p = 0.086). In both treatment arms, pCR, TRG and NAR were significant prognostic factors for DFS, whereas survival in subgroups defined by pCR, TRG or NAR did not significantly differ between the treatment arms. The discrimination ability of non-pCR for DFS remained constant over time (C-Index 0.58) but was slightly better in Arm B (0.61 vs. 0.56). Conclusion: Although pCR, TRG and NAR were strong prognostic factors for DFS in the CAO/ARO/AIO-12 trial, their value in selecting one TNT approach over another could not be confirmed. Hence, the conclusion of a long-term survival benefit of one treatment arm based on early surrogate endpoints should be stated with caution.