Prognostic significance of survivin in rectal cancer patients treated with surgery and postoperative concurrent chemo-radiation therapy

Survivin Small Molecules Inhibitors: Recent Advances and Challenges

Survivin, as a member of the inhibitor of apoptosis proteins (IAPs) family, acts as a suppressor of apoptosis and plays a central role in cell division. Survivin has been considered as an important cancer drug target because it is highly expressed in many types of human cancers, while it is effectively absent from terminally differentiated normal tissues. Moreover, survivin is involved in tumor cell resistance to chemotherapy and radiation. Preclinically, downregulation of survivin expression or function reduced tumor growth induced apoptosis and sensitized tumor cells to radiation and chemotherapy in different human tumor models. This review highlights the role of survivin in promoting cellular proliferation and inhibiting apoptosis and summarizes the recent advances in and challenges of developing small-molecule survivin inhibitors.

Tissue-Based Markers as a Tool to Assess Response to Neoadjuvant Radiotherapy in Rectal Cancer-Systematic Review

According to current guidelines, the current treatment for locally advanced rectal cancer is neoadjuvant therapy, followed by a total mesorectal excision. However, radiosensitivity tends to differ among patients due to tumor heterogeneity, making it difficult to predict the possible outcomes of the neoadjuvant therapy. This review aims to investigate different types of tissue-based biomarkers and their capability of predicting tumor response to neoadjuvant therapy in patients with locally advanced rectal cancer. We identified 169 abstracts in NCBI PubMed, selected 48 reports considered to meet inclusion criteria and performed this systematic review. Multiple classes of molecular biomarkers, such as proteins, DNA, micro-RNA or tumor immune microenvironment, were studied as potential predictors for rectal cancer response; nonetheless, no literature to date has provided enough sufficient evidence for any of them to be introduced into clinical practice.

Prognostic Factors and Treatment of Recurrence after Local Excision of Rectal Cancer

PURPOSE

Indications for local excision in patients with rectal cancer remain controversial. We reviewed factors affecting survival rate and treatment effectiveness in cancer recurrence after local excision among patients with rectal cancer.

MATERIALS AND METHODS

A total of 831 patients was enrolled. Of these, 391 patients were diagnosed with primary rectal cancer and underwent local excision. A retrospective observational study was performed on patients who underwent full-thickness local excision for rectal cancer.

RESULTS

The median duration of follow-up was 61 months. The overall recurrence rate was 11.5%. The rate of local recurrence was 5.1%. Five-year overall survival rate among recurrent patients was 66.8%; the rate among patients who underwent salvage operation due to recurrence was 84.7%, compared with 44.2% among patients treated with non-operative management (p<0.001). Multivariate analysis of disease-free survival identified distance from the anal verge (p=0.038) and histologic grade (p=0.047) as factors predicting poor prognosis. Multivariate analysis of overall survival showed that age (p<0.001), serum carcinoembryonic antigen (CEA) levels (p=0.001), and histologic grade (p=0.013) also affected poor prognosis. In subgroup analysis of patients with recurrence, 25 patients underwent reoperation, while 20 patients did not. For 5-year overall survival rate, there was a significant difference between 84.7% of the reoperation group and 44.2% of the non-operation group (p<0.001).

CONCLUSION

The risk factors affecting overall survival rate after local excision were age 65 years or older, preoperative CEA level 5 or higher, and high histologic grade. In cases of recurrence after local excision of rectal cancer, salvage operation might improve overall survival.

Non-operative management of rectal cancer: understanding tumor biology

The management of locally-advanced rectal cancer involves a combination of chemotherapy, chemoradiation, and surgical resection to provide excellent local tumor control and overall survival. However, aspects of this multimodality approach are associated with significant morbidity and long-term sequelae. In addition, there is growing evidence that patients with a clinical complete response to chemotherapy and chemoradiation treatments may be safely offered initial non-operative management in a rigorous surveillance program. Weighed against the morbidity and significant sequelae of rectal resection, recognizing how to best optimize non-operative strategies without compromising oncologic outcomes is critical to our understanding and treatment of this disease.

Targeting survivin for therapeutic discovery: past, present, and future promises

Survivin, the smallest member of the inhibitor of apoptosis protein (IAP) family, is overexpressed in cells of almost all cancers but not in most normal tissues in adults. Survivin expression is required for cancer cell survival and knocking down its expression or inhibiting its function using molecular approaches results in spontaneous apoptosis. Thus, survivin is an attractive and perhaps ideal target for cancer drug discovery. However, a US Food and Drug Administration (FDA)-approved drug targeting survivin has yet to emerge. In this Foundation Review, we examine and evaluate various strategies that have been used to target survivin and the stages of each survivin inhibitor to help understand this lack of success. We also provide future perspectives moving forward in targeting survivin for drug discovery.

Predictive and Prognostic Molecular Biomarkers for Response to Neoadjuvant Chemoradiation in Rectal Cancer

The standard of care in locally advanced rectal cancer is neoadjuvant chemoradiation (nCRT) followed by radical surgery. Response to nCRT varies among patients and pathological complete response is associated with better outcome. However, there is a lack of effective methods to select rectal cancer patients who would or would not have a benefit from nCRT. The utility of clinicopathological and radiological features are limited due to lack of adequate sensitivity and specificity. Molecular biomarkers have the potential to predict response to nCRT at an early time point, but none have currently reached the clinic. Integration of diverse types of biomarkers including clinicopathological and imaging features, identification of mechanistic link to tumor biology, and rigorous validation using samples which represent disease heterogeneity, will allow to develop a sensitive and cost-effective molecular biomarker panel for precision medicine in rectal cancer. Here, we aim to review the recent advance in tissue- and blood-based molecular biomarker research and illustrate their potential in predicting nCRT response in rectal cancer.