Pathological complete response after neoadjuvant therapy for rectal cancer and the role of adjuvant therapy

Magnetic resonance imaging-based radiomics nomogram for the evaluation of therapeutic responses to neoadjuvant chemohormonal therapy in high-risk non-metastatic prostate cancer

PURPOSE

The aim of this study was to assess the potential application of a radiomics features-based nomogram for predicting therapeutic responses to neoadjuvant chemohormonal therapy (NCHT) in patients with high-risk non-metastatic prostate cancer (PCa).

METHODS

Clinicopathologic information was retrospectively collected from 162 patients with high-risk non-metastatic PCa receiving NCHT and radical prostatectomy at our center. The postoperative pathological findings were used as the gold standard for evaluating the efficacy of NCHT. The least absolute shrinkage and selection operator (LASSO) was conducted to develop radiomics signature. Multivariate logistic regression analyses were conducted to identify the predictors of a positive pathological response to NCHT, and a nomogram was constructed based on these predictors.

RESULTS

Sixty-three patients (38.89%) experienced positive pathological response to NCHT. Receiver operating characteristic analyses showed that the area under the curve (AUC) of periprostatic fat (PPF) radiomics signature was 0.835 (95% CI, 0.754-0.898), while the AUC of intratumoral radiomics signature was 0.822 (95% CI, 0.739-0.888). Multivariate logistic regression analysis revealed that PSA level, PPF radiomics signature and intratumoral radiomics signature were independent predictors of positive pathological response. A nomogram based on these three predictors was constructed. The AUC was 0.908 (95% CI, 0.839-0.954). The Hosmer-Lemeshow goodness-of-fit test showed that the nomogram was well calibrated. Decision curve analysis revealed the favorable clinical practicability of the nomogram. The nomogram was successfully validated in the validation cohort. Kaplan-Meier analyses showed that nomogram and positive pathological response were significantly related with survival of PCa.

CONCLUSION

The radiomics-clinical nomogram based on mpMRI radiomics features exhibited superior predictive ability for positive pathological response to NCHT in high-risk non-metastatic PCa.

Pre-Treatment Computed Tomography Radiomics for Predicting the Response to Neoadjuvant Chemoradiation in Locally Advanced Rectal Cancer: A Retrospective Study

Background and Purpose

Computerized tomography (CT) scans are commonly performed to assist in diagnosis and treatment of locally advanced rectal cancer (LARC). This study assessed the usefulness of pretreatment CT-based radiomics for predicting pathological complete response (pCR) of LARC to neoadjuvant chemoradiotherapy (nCRT).

Materials and Methods

Patients with LARC who underwent nCRT followed by total mesorectal excision surgery from July 2010 to December 2018 were enrolled in this retrospective study. A total of 340 radiomic features were extracted from pretreatment contrast-enhanced CT images. The most relevant features to pCR were selected using the least absolute shrinkage and selection operator (LASSO) method and a radiomic signature was generated. Predictive models were built with radiomic features and clinico-pathological variables. Model performance was assessed with decision curve analysis and was validated in an independent cohort.

Results

The pCR was achieved in 44 of the 216 consecutive patients (20.4%) in this study. The model with the best performance used both radiomics and clinical variables including radiomic signatures, distance to anal verge, lymphocyte-to-monocyte ratio, and carcinoembryonic antigen. This combined model discriminated between patients with and without pCR with an area under the curve of 0.926 and 0.872 in the training and the validation cohorts, respectively. The combined model also showed better performance than models built with radiomic or clinical variables alone.

Conclusion

Our combined predictive model was robust in differentiating patients with and without response to nCRT.

Predictive Significance of Mucinous Histology on Pathologic Complete Response Rate Following Capecitabine-Based Neoadjuvant Chemoradiation in Rectal Cancer: a Comparative Study

INTRODUCTION

Currently, neoadjuvant fluoropyrimidine-based chemoradiation followed by surgery is considered the standard of care for locally advanced rectal cancer. The current study aimed to investigate the predictive significance of mucinous histology on the pathologic complete response rate following neoadjuvant chemoradiation in locally advanced rectal cancer and to propose potential new treatment protocol for this specific histology.

MATERIAL AND METHOD

This retrospective study was conducted on 403 patients with locally advanced (clinically T3-4 and/or N1-2) rectal adenocarcinoma who had been treated at three tertiary academic hospitals between 2010 and 2015. Among those 403 patients, 46 (11%) had mucinous rectal cancer (MRC) and 358 (89%) had non-mucinous rectal cancer (NMRC). All patients underwent neoadjuvant chemoradiation with capecitabine followed by low anterior or abdominoperineal resection.

RESULTS

There were 268 men and 135 women with a median age of 55 years (range, 26-82 years). Patients with MRC were younger (p = 0.002) and presented with a larger tumor size (p < 0.001) and a more advanced tumor stage (p = 0.033) compared to the ones with MNRC. In the univariate analysis, female gender (p = 0.009), distal tumor location (p = 0.035), higher tumor stage (p = 0.049), node positivity (p = 0.001), MRC histology (p = 0.017), and high pretreatment CEA level (p = 0.013) were observed to be predictive of a poor pathologic complete response. However, in the multivariate analysis, tumor stage was the single most predictive factor of response to neoadjuvant chemoradiation.

CONCLUSION

Mucinous adenocarcinoma is a significant predictive factor for poor pathologic complete response to neoadjuvant capecitabine-based chemoradiation in patients with locally advanced rectal cancer. New treatment modality based on biomarkers may be considered in future prospective studies because of MRC poor prognosis. Immunotherapy combined with chemotherapy and/or radiotherapy may be an attractive option because of the tumor microsatellite instability-high status.

Improved survival with adjuvant chemotherapy in locally advanced rectal cancer patients treated with preoperative chemoradiation regardless of pathologic response

OBJECTIVE

The aim of this study is to examine the effect of postoperative chemotherapy on survival in patients with stage II or III rectal adenocarcinoma who undergo neoadjuvant chemoradiation (CRT) and surgical resection.

METHODS

A retrospective review of the National Cancer Database (NCDB) from 2006 to 2013 was performed. Cases were analyzed based on pathologic complete response (pCR) status and use of adjuvant therapy. The Kaplan-Meier method was used to estimate overall survival probabilities.

RESULTS

23,045 cases were identified, of which 5832 (25.31%) achieved pCR. In the pCR group, 1513 (25.9%) received adjuvant chemotherapy, and in the non-pCR group, 5966 (34.7%) received adjuvant therapy. In the pCR group, five-year survival probability was 87% (95% CI 84%-89%) with adjuvant therapy and 81% (95% CI 79%-82%) without adjuvant therapy. In the non-pCR group, five-year survival probability was 78% (95% CI 76%-79%) with adjuvant therapy and 70% (95% CI 69%-71%) without adjuvant therapy. In the non-pCR and node-negative subgroup (ypN-), five-year survival probability was 86% (95% CI 84%-88%) with adjuvant therapy and 76% (95% CI 74%-77%) without adjuvant therapy. In the non-pCR and node-positive subgroup (ypN+), five-year survival probability was 67% (95% CI 65%-70%) with adjuvant therapy and 60% (95% CI 58%-63%) without adjuvant therapy.

CONCLUSIONS

Adjuvant chemotherapy in stage II or III rectal adenocarcinoma is associated with increased five-year survival probability regardless of pCR status. We observed similar survival outcomes among non-pCR ypN- treated with adjuvant chemotherapy compared with patients achieving pCR treated with adjuvant chemotherapy.

Disease extent at secondary cytoreductive surgery is predictive of progression-free and overall survival in advanced stage ovarian cancer: An NRG Oncology/Gynecologic Oncology Group study

PURPOSE

GOG 152 was a randomized trial of secondary cytoreductive surgery (SCS) in patients with suboptimal residual disease (residual tumor nodule >1cm in greatest diameter) following primary cytoreductive surgery for advanced stage ovarian cancer. The current analysis was undertaken to evaluate the impact of disease findings at SCS on progression-free survival (PFS) and overall survival (OS).

METHODS

Among the 550 patients enrolled on GOG-152, two-hundred-sixteen patients were randomly assigned following 3cycles of cisplatin and paclitaxel to receive SCS. In 15 patients (7%) surgery was declined or contraindicated. In the remaining 201 patients the operative and pathology reports were utilized to classify their disease status at the beginning of SCS as; no gross disease/microscopically negative N=40 (19.9%), no gross disease/microscopically positive N=8 (4.0%), and gross disease N=153 (76.1%).

RESULTS

The median PFS for patients with no gross disease/microscopically negative was 16.1months, no gross disease/microscopically positive was 13.5months and for gross disease was 11.7months, P=0.002. The median OS for patients with no gross disease/microscopically negative was 51.5months, no gross disease/microscopically positive was 42.6months and for gross disease was 34.9months, P=0.018.

CONCLUSION

Although as previously reported SCS did not change PFS or OS, for those who underwent the procedure, their operative and pathologic findings were predictive of PFS and OS. Surgical/pathological residual disease is a biomarker of response to chemotherapy and predictive of PFS and OS.

Recent surgical advances in colorectal cancer excision: toward optimal outcomes

Colorectal cancer is the third most common cancer affecting both males and females in the western world. Despite all the developments in the current treatment of colorectal cancer, it is still continuing to be an important factor of patient morbidity and mortality worldwide. Surgery is the mainstay of treatment for colorectal cancer. Over the last decade, there have been major changes and developments in the surgical treatment. Understanding the importance of the anatomy, technological advances in minimally invasive surgery and effects of chemoradiotherapy have changed the approaches to colorectal cancer treatment. Today, novel treatment strategies must be targeted not only minimally invasive approaches, but also aiming to increase patients’ quality of life without compromising the oncological principles.

Advances for achieving a pathological complete response for rectal cancer after neoadjuvant therapy

Neoadjuvant therapy has become the standard of care for locally advanced mid-low rectal cancer. Pathological complete response (pCR) can be achieved in 12%–38% of patients. Patients with pCR have the most favorable long-term outcomes. Intensifying neoadjuvant therapy and extending the interval between termination of neoadjuvant treatment and surgery may increase the pCR rate. Growing evidence has raised the issue of whether local excision or observation rather than radical surgery is an alternative for patients who achieve a clinical complete response after neoadjuvant therapy. Herein, we highlight many of the advances and resultant controversies that are likely to dominate the research agenda for pCR of rectal cancer in the modern era.

Advances and challenges in treatment of locally advanced rectal cancer

Dramatic improvements in the outcomes of patients with rectal cancer have occurred over the past 30 years. Advances in surgical pathology, refinements in surgical techniques and instrumentation, new imaging modalities, and the widespread use of neoadjuvant therapy have all contributed to these improvements. Several questions emerge as we learn of the benefits or lack thereof for components of the current multimodality treatment in subgroups of patients with nonmetastatic locally advanced rectal cancer (LARC). What is the optimal surgical technique for distal rectal cancers? Do all patients need postoperative chemotherapy? Do all patients need radiation? Do all patients need surgery, or is a nonoperative, organ-preserving approach warranted in selected patients? Answering these questions will lead to more precise treatment regimens, based on patient and tumor characteristics, that will improve outcomes while preserving quality of life. However, the idea of shifting the treatment paradigm (chemoradiotherapy, total mesorectal excision, and adjuvant therapy) currently applied to all patients with LARC to a more individually tailored approach is controversial. The paradigm shift toward organ preservation in highly selected patients whose tumors demonstrate clinical complete response to neoadjuvant treatment is also controversial. Herein, we highlight many of the advances and resultant controversies that are likely to dominate the research agenda for LARC in the modern era.

Time to adjuvant chemotherapy and survival outcomes among patients with stage 2 to 3 rectal cancer treated with preoperative chemoradiation

BACKGROUND

Previous studies have evaluated the impact of time to adjuvant chemotherapy (AC) on survival in early-stage colon cancer. However, the optimal time to adjuvant chemotherapy (TTAC) in rectal cancer remains unclear. The objective of this study was to identify an optimal TTAC and determine its prognostic effect in stage 2 to 3 rectal cancer.

METHODS

Patients with stage 2 to 3 rectal cancer treated with preoperative chemoradiation and postoperative AC between 1999 and 2008 were included. Predetermined time points of 4, 6, 8, and 12 weeks from date of surgery were analyzed. Cut-point analysis was then used to determine an optimal TTAC, and overall survival at the identified cut-point was evaluated.

RESULTS

A total of 328 eligible patients were identified with a median age of 61 years (range 22-85 years), 70% male, and 75% stage 3 disease. The median TTAC was 7.0 weeks. Initiation of AC at 6 weeks from date of surgery was associated with a significant survival benefit (hazard ratio 0.52, 95% confidence interval 0.31-0.90, P = .017), while no significant association was seen at 4, 8 or 12 weeks (P > .05). The cut-point analysis identified an optimal TTAC of 5.6 weeks association with improved survival compared to those with a TTAC greater than 5.6 weeks (hazard ratio 0.42, 95% confidence interval 0.22-0.82, P = .0087). This cut-point was also found to be a significant prognostic factor in multivariable analysis (P = .04) adjusted for Eastern Cooperative Oncology Group performance status, age, gender, stage, margin status, and grade.

CONCLUSIONS

This study suggests that initiation of AC within an earlier time frame is associated with improved overall survival.

Differences in colon and rectal cancer chemosensitivity

SUMMARY Adjuvant chemotherapy of rectal cancer is not well established. The aim of this review was to compare results of adjuvant treatment of colon and rectal cancer to identify possible clues for the differences in chemosensitivity. Adjuvant chemotherapy of 5-fluorouracil with folinic acid increased survival in colon cancer, but not in rectal cancer. A similar trend is seen for the addition of oxaliplatin. Using identical adjuvant treatment in colon and rectal cancer revealed a similar frequency of liver metastases, but a significant difference in the occurrence of lung (7.3 vs 12.7%) and peritoneal metastases (8.9 vs 4.0%). We hypothesize that the observed difference may be due to the influence of the microenvironment and differences in the expression of resistance genes such as the gene coding for thymidylate synthase. In conclusion, the differing effectiveness of adjuvant treatment of rectal and colon cancer may at least in part be caused by differing patterns of metastases associated with differing chemosensitivity.