Neoadjuvant chemoradiation for locally advanced rectal cancer: a systematic review of the literature with network meta-analysis

Targeted Therapy in the Palliative Setting of Colorectal Cancer-Survival and Medical Costs

(1) Background: Targeted therapy is used alone or together with chemotherapy in metastatic colorectal cancer. The aim of this study was to assess overall survival and medical costs in a cohort of patients with metastatic colorectal cancer. (2) Methods: Demographic and clinical characteristics of 337 patients and pathological data of colorectal tumors were retrospectively collected in this population-based study. The overall survival and medical costs for patients receiving chemotherapy plus targeted therapy were compared with those for patients receiving chemotherapy only. (3) Results: Patients administered chemotherapy plus targeted therapy were less frail and had more often RAS wild-type tumors but had higher CEA levels than patients receiving chemotherapy only. No prolonged overall survival could be observed in patients receiving palliative targeted therapy. The medical costs for patients undergoing treatment with targeted therapy were significantly higher than for patients treated only with chemotherapy; they were especially higher in the group receiving targeted therapy early than late in the palliative setting. (4) Conclusions: The use of targeted therapy in metastatic colorectal cancer leads to significantly higher medical costs when used early in the palliative setting. No positive effects of the use of targeted therapy could be observed in this study; therefore, we suggest that targeted therapy be used in later lines of palliative therapy in metastatic colorectal cancer.

Whole lesion histogram analysis of apparent diffusion coefficient predicts therapy response in locally advanced rectal cancer

BACKGROUND

Whole-tumor apparent diffusion coefficient (ADC) histogram analysis is relevant to predicting the neoadjuvant chemoradiation therapy (nCRT) response in patients with locally advanced rectal cancer (LARC).

AIM

To evaluate the performance of ADC histogram-derived parameters for predicting the outcomes of patients with LARC.

METHODS

This is a single-center, retrospective study, which included 48 patients with LARC. All patients underwent a pre-treatment magnetic resonance imaging (MRI) scan for primary tumor staging and a second restaging MRI for response evaluation. The sample was distributed as follows: 18 responder patients (R) and 30 non-responders (non-R). Eight parameters derived from the whole-lesion histogram analysis (ADCmean, skewness, kurtosis, and ADC10^th, 25^th, 50^th, 75^th, 90^th percentiles), as well as the ADCmean from the hot spot region of interest (ROI), were calculated for each patient before and after treatment. Then all data were compared between R and non-R using the Mann-Whitney U test. Two measures of diagnostic accuracy were applied: the receiver operating characteristic curve and the diagnostic odds ratio (DOR). We also reported intra- and interobserver variability by calculating the intraclass correlation coefficient (ICC).

RESULTS

Post-nCRT kurtosis, as well as post-nCRT skewness, were significantly lower in R than in non-R (both P < 0.001, respectively). We also found that, after treatment, R had a larger loss of both kurtosis and skewness than non-R (∆%kurtosis and ∆skewness, P < 0.001). Other parameters that demonstrated changes between groups were post-nCRT ADC10^th, ∆%ADC10^th, ∆%ADCmean, and ROI ∆%ADCmean. However, the best diagnostic performance was achieved by ∆%kurtosis at a threshold of 11.85% (Area under the receiver operating characteristic curve [AUC] = 0.991, DOR = 376), followed by post-nCRT kurtosis = 0.78 × 10^-3 mm²/s (AUC = 0.985, DOR = 375.3), ∆skewness = 0.16 (AUC = 0.885, DOR = 192.2) and post-nCRT skewness = 1.59 × 10^-3 mm²/s (AUC = 0.815, DOR = 168.6). Finally, intraclass correlation coefficient analysis showed excellent intraobserver and interobserver agreement, ensuring the implementation of histogram analysis into routine clinical practice.

CONCLUSION

Whole-tumor ADC histogram parameters, particularly kurtosis and skewness, are relevant biomarkers for predicting the nCRT response in LARC. Both parameters appear to be more reliable than ADCmean from one-slice ROI.

Oncological outcomes of multimodality treatment for patients undergoing surgery for locally recurrent rectal cancer: A systematic review

BACKGROUND

There are several strategies in the management of locally recurrent rectal cancer (LRRC) with the optimum treatment yet to be established. This systematic review aims to compare oncological outcomes in patients undergoing surgery for LRRC who underwent neoadjuvant radiotherapy or chemoradiotherapy (CRT), adjuvant CRT, surgery only or surgery and intraoperative radiotherapy (IORT).

METHODS

A literature search of MEDLINE, EMBASE and CINAHL was performed for studies that reported data on oncological outcomes for the different treatment modalities in patients with LRRC from January 1990 to January 2022. Weighted means were calculated for the following outcomes: postoperative resection status, local control, and overall survival at 3 and 5 years.

RESULTS

Fifteen studies of 974 patients were included and they received the following treatment: 346 neoadjuvant radiotherapy, 279 neoadjuvant CRT, 136 adjuvant CRT, 189 surgery only, and 24 surgery and IORT. The highest proportion of R0 resection was found in the neoadjuvant CRT group followed by neoadjuvant radiotherapy and adjuvant CRT groups (64.07% vs 52.46% vs 47.0% respectively). The neoadjuvant CRT group had the highest mean 5-year local control rate (49.50%) followed by neoadjuvant radiotherapy (22.0%). Regarding the 5-year overall survival rate, the neoadjuvant CRT group had the highest mean of 34.92%, followed by surgery only (29.74%), neoadjuvant radiotherapy (28.94%) and adjuvant CRT (20.67%).

CONCLUSIONS

The findings of this systematic review suggest that neoadjuvant CRT followed by surgery can lead to improved resection status, long-term disease control and survival in the management of LRRC. However, treatment strategies in LRRC are complex and further comparisons, particularly taking into account previous treatments for the primary rectal cancer, are required.

Radiation and chemotherapy variable response induced by tumor cell hypoxia: impact of radiation dose, anticancer drug, and type of cancer

Hypoxia is a condition in which proliferating tumor cells are deprived of oxygen due to limited blood supply from abnormal tumor microvasculature. This study aimed to investigate the molecular changes that occur in tumor cell hypoxia with special emphasis placed on the efficacy of chemotherapeutic and radiation-related effects. Four commercially available chemotherapeutic agents: cisplatin, cyclophosphamide, doxorubicin, and 5-fluorouracil, were tested for their cytotoxic activity on the cancer cell lines PC3 (prostate), HepG2 (liver), and MCF-7 (breast). Tumor cell lines under hypoxia were treated with both IC₅₀ concentrations of the different chemotherapeutic agents and irradiated with 5 and 10 Gy using a ¹³⁷Cs gamma source. Hypoxia-inducible factor-1α (HIF-1α) protein levels were examined using an ELISA assay. Hypoxic cells showed a significant change in cell viability to all chemotherapeutic agents in comparison to normoxic controls. HepG2 cells were more resistant to the cytotoxic drug doxorubicin compared to other cancer cell lines. The flow cytometric analysis showed that hypoxic cells have lower levels of total apoptotic cell populations (early and late apoptosis) compared to normoxic cells suggesting decreased hypoxia-induced apoptosis in cancer cells. The highest reduction in HIF-1α level was observed in the MCF-7 cell line (95.5%) in response to the doxorubicin treatment combined with 10 Gy irradiation of cells. Chemoradiotherapy could result in minimal as well as a high reduction of HIF-1α based on cell type, type of chemotherapy, and amount of ionizing radiation. This study highlights future research work to optimize a combined chemoradiotherapeutic regime in individual cancer cell hypoxia.

A multicenter phase II trial of preoperative chemoradiotherapy with S-1 plus oxaliplatin and bevacizumab for locally advanced rectal cancer

BACKGROUND

We clarified the safety and efficacy of preoperative chemoradiotherapy for locally advanced rectal cancer using a multidrug regimen (S-1 + oxaliplatin + bevacizumab).

METHODS

This multicenter phase II trial involved 47 patients with locally advanced rectal cancer. All patients received S-1 orally (80 mg/m²/day on days 1-5, 8-12, 15-19, and 22-26) and infusions of oxaliplatin (50 mg/m² on days 1, 8, 15, and 22) and bevacizumab (5 mg/kg on days 1 and 15). The total radiation dose was 40 Gy delivered in daily fractions of 2 Gy via the four-field technique. The primary endpoint was the pathological complete response rate. The secondary endpoints were safety (incidence of adverse events) and clinical response, relapse-free survival, overall survival, local recurrence, R0 resection, downstaging, and treatment completion rates.

RESULTS

All 47 patients received chemoradiotherapy, and 44 patients underwent curative resection. Two patients refused surgery and selected a watch-and-wait strategy. The pathological complete response rate was 18.2% in patients who underwent curative resection. The clinical response rate was 91.3% in 46 patients. Concerning hematotoxicity, there was one grade 4 adverse event (2.1%) and seven grade 3 events (14.9%). Diarrhea was the most frequent non-hematotoxic event, and the grade 3 event rate was 25.5%.

CONCLUSIONS

Although preoperative chemoradiotherapy for patients with locally advanced rectal cancer using the S-1 + oxaliplatin + bevacizumab regimen did not achieve the expected pathological complete response rate, this regimen led to an improved clinical response rate.

Adding Adjuvants to Fluoropyrimidine-based Neoadjuvant Chemoradiotherapy for Locally Advanced Rectal Cancer: An Option Worthy of Serious Consideration

The application of fluoropyrimidine-based neoadjuvant chemoradiotherapy (Fu-nCRT) of locally advanced rectal cancer (LARC) has become a common therapeutic regimen. In order to improve the efficacy and enable more patients to benefit from this treatment, an accumulation of studies have been carried out on the auxiliary use of other drugs with Fu-nCRT. However, due to specific challenges and the potential opportunities that coexist in this field, a more reasonable approach to the mode of treatment remains to be explored. In this review, we have summarized the results of the studies on the combination of Fu-nCRT with cytotoxic drugs, anti-tumor angiogenesis, and anti-EGFR agents, as well as the status of the application of immune checkpoint inhibitors in the neoadjuvant therapy of LARC patients.

The impact of circumferential tumour location on the clinical outcome of rectal cancer patients managed with neoadjuvant chemoradiotherapy followed by total mesorectal excision

AIM

To investigate the impact of circumferential tumour location on neoadjuvant chemoradiotherapy (CRT) response and its prognostic value for locally advanced rectal cancer (LARC) patients after CRT and surgery.

METHODS

A retrospective study was performed on 486 patients with LARC who received neoadjuvant CRT and surgical treatment. The rate of pathological complete response (pCR) and survival among patients with anteriorly, laterally, and posteriorly located tumours were compared. Logistic regression was performed to identify pCR predictors.

RESULTS

The anterior tumours exhibited the highest pCR rate of 26.7%, which was slightly higher than the 20.0% and 12.3% for lateral and posterior tumours, respectively (P = 0.006). The 5-year Overall survival (OS) rates after CRT were similar among the anterior, lateral, and posterior groups (anterior vs lateral vs posterior: 81.1% vs 89.9% vs 84.1%, P = 0.6368). Multivariate analysis revealed that the circumferential tumour location, post-CRT serum CEA and post-CRT tumour thickness measured by MRI were independently correlated with achieving pCR.

CONCLUSION

This study is the first, to the best of our knowledge, to show that anterior LARC exhibited the highest pCR rate after neoadjuvant CRT. Patients with anterior rectal cancers do not have different prognoses from those with non-anterior cancers if they undergo neoadjuvant CRT.

Predicting poor response to neoadjuvant chemoradiotherapy for locally advanced rectal cancer: Model constructed using pre-treatment MRI features of structured report template

PURPOSE

To develop a predictive model with pre-treatment magnetic resonance imaging (MRI) findings of the structured report template and clinical parameters for poor responses prediction after neoadjuvant chemoradiotherapy (neoCRT) in locally advanced rectal cancers (LARC) patients.

METHOD

Patients with clinicopathologically confirmed LARC (training and validation datasets, n = 100 and 71, respectively) were enrolled. Patients' clinical data were retrospectively collected. MRI findings of the structured report template were analysed. The tumour regression grade (TRG) system as proposed by Mandard et al was used. Poor response was defined as TRG 3-5. Univariate logistic regression analysis and a lasso regression model were performed to select the significant predictive features from the training set. A nomogram was constructed based on a multivariable logistic regression analysis. Calibration, discrimination, and clinical usefulness of the nomogram were assessed. The calibrative and discriminative ability of our model were compared with those of models including the tumour-node-metastasis (TNM) stage and clinical factors.

RESULTS

The MRI-reported T4b stage, MRI-reported extramural venous invasion (EMVI) positivity, MRI-detected number of positive mesorectal lymph nodes (LNs) > 0, and preoperative oxaliplatin and capecitabine (CAPOX) chemotherapy regimen were incorporated into our nomogram. The nomogram showed good discrimination, with areas under the receiver operating characteristic (ROC) curves of 0·823 and 0·820 in the training and test sets, respectively, and good calibration in both datasets. The decision curve analysis confirmed that the nomogram was clinically useful. The calibrative and discriminative ability of our model were better than those models including the TNM stage and clinical factors.

CONCLUSION

A nomogram based on pre-treatment MRI features of the structured report template and clinical risk factors has potential for use as a non-invasive tool to preoperatively predict poor responses in LARC patients after neoCRT.