A Review of Neoadjuvant Chemoradiotherapy for Locally Advanced Rectal Cancer

RBBP6 increases radioresistance and serves as a therapeutic target for preoperative radiotherapy in colorectal cancer

Radiotherapy (RT) can be used as preoperative treatment to downstage initially unresectable locally rectal carcinoma, but radioresistance and recurrence remain significant problems. Retinoblastoma binding protein 6 (RBBP6) has been implicated in the regulation of cell cycle, apoptosis and chemoresistance both in vitro and in vivo. The present study investigated whether the inhibition of RBBP6 expression would improve radiosensitivity in human colorectal cancer cells. After SW620 and HT29 cells were exposed to radiation, the levels of RBBP6 mRNA and protein increased over time in both cells. Moreover, a significant reduction in clonogenic survival and a decrease in cell viability in parallel with an obvious increase in cell apoptosis were demonstrated in irradiated RBBP6‐knockdown cells. Transfection with RBBP6 shRNA improved the levels of G2‐M phase arrest, which blocked the cells in a more radiosensitive period of the cell cycle. These observations indicated that cell cycle and apoptosis mechanisms may be connected with tumor cell survival following radiotherapy. In vivo, the tumor growth rate of nude mice in the RBBP6‐knockdown group was significantly slower than that in other groups. These results indicated that RBBP6 overexpression could resist colorectal cancer cells against radiation by regulating cell cycle and apoptosis pathways, and inhibition of RBBP6 could enhance radiosensitivity of human colorectal cancer.

Role of Chemotherapy in the Neoadjuvant/Adjuvant Setting for Patients With Rectal Adenocarcinoma Undergoing Chemoradiotherapy and Surgery or Radiotherapy and Surgery

Rectal cancer has been successfully managed in the last couple of decades. In the USA, as the initial approach, neoadjuvant concurrent chemoradiation has been associated not only with decrease in tumor size and recurrence but also with higher resection rate with minimal side effects. Data support that addition of chemotherapy to radiotherapy is superior to radiotherapy alone in the neoadjuvant setting. Recent debates have addressed the question of administration of adjuvant chemotherapy following surgery. In this article, we discuss the role of chemotherapy in both the neoadjuvant and the adjuvant settings for locally advanced rectal cancer.

Predictive factors for early- and late-onset surgical site infections in patients undergoing elective colorectal surgery. A multicentre, prospective, cohort study

BACKGROUND

Surgical site infections (SSIs) are the leading cause of healthcare-associated infections in acute care hospitals in Europe. However, the risk factors for the development of early-onset (EO) and late-onset (LO) SSI have not been elucidated.

AIM

This study investigated the predictive factors for EO-SSI and LO-SSI in a large cohort of patients undergoing colorectal surgery.

METHODS

We prospectively followed-up adult patients undergoing elective colorectal surgery in 10 hospitals (2011-2014). Patients were divided into three groups: EO-SSI, LO-SSI, or no infection (no-SSI). The cut-off defining EO-SSI and LO-SSI was seven days (median time to SSI development). Different predictive factors for EO-SSI and LO-SSI were analysed, comparing each group with the no-SSI patients.

FINDINGS

Of 3701 patients, 320 (8.6%) and 349 (9.4%) developed EO-SSI and LO-SSI, respectively. The rest had no-SSI. Patients with EO-SSI were mostly males, had colon surgery and developed organ-space SSI whereas LO-SSI patients frequently received chemotherapy or radiotherapy and had incisional SSI. Male sex (odds ratio (OR): 1.92; P < 0.001), American Society of Anesthesiologists' physical status >2 (OR: 1.51; P = 0.01), administration of mechanical bowel preparation (OR: 0.7; P = 0.03) and stoma creation (OR: 1.95; P < 0.001) predicted EO-SSI whereas rectal surgery (OR: 1.43; P = 0.03), prolonged surgery (OR: 1.4; P = 0.03) and previous chemotherapy (OR: 1.8; P = 0.03) predicted LO-SSI.

CONCLUSION

We found distinctive predictive factors for the development of SSI before and after seven days following elective colorectal surgery. These factors could help establish specific preventive measures in each group.

Morphologic predictors of pathological complete response to neoadjuvant chemoradiotherapy in locally advanced rectal cancer

Purpose

To evaluate the value of morphological parameters that can be obtained conveniently by MRI for predicting pathologically complete response (pCR) in patients with rectal cancer.

Materials and Methods

A cohort of 101 patients was examined using MRI before and after Neoadjuvant chemoradiotherapy (nCRT). Morphological parameters including maximum tumor area (MTA), maximum tumor length (MTL) and maximum tumor thickness (MTT), as well as cylindrical approximated tumor volume (CATV), distance to anal verge (DTA), and the reduction rates were evaluated by two experienced readers independently.

Results

Post-nCRT MTA and MTL, reduction rates and pre-nCRT DTA were proved to be significantly different between pCR and non-pCR with the AUCs of 0.672-0.853. The sensitivity and specificity for assessing pCR were 61.1-89.9% and 59.0-80.7% respectively. No significant correlation between pre-nCRT size measurements and pCR was obtained.

Conclusion

The convenient morphological measurements may be useful for predicting pCR with moderate sensitivity and specificity. Combining these predictors with the aim of building diagnostic model should be explored.

Pim-3 as a potential predictor of chemoradiotherapy resistance in locally advanced rectal cancer patients

Approximately 30% of locally advanced rectal cancer patients might not benefit from chemoradiotherapy; however, the response to neoadjuvant chemoradiotherapy in these cases is difficult to predict. Pim-3 is a member of the provirus integration site for a moloney murine leukemia virus family of proteins that contributes to cell proliferation, survival, and chemotherapy resistance. Therefore, the relationship between Pim-3 expression and response to neoadjuvant chemoradiotherapy in rectal cancer patients is important to evaluate. 175 rectal cancer patients who underwent neoadjuvant treatment enrolled in this study. The relationship between Pim-3 expression on immunohistochemical analysis of rectal cancer tissue, which was obtained before treatment, the response to chemoradiotherapy and survival was investigated. The patients with no Pim-3 expression were more likely to achieve a pathologic complete response to chemoradiotherapy than patients with Pim-3 expression (P = 0.001). Cox multivariate analysis showed that the significant prognostic factors were Pim-3 expression (P = 0.003) and the number of neoadjuvant chemotherapy cycles (P = 0.005) for overall survival. Neoadjuvant chemotherapy cycles (P = 0.007), adjuvant chemotherapy cycles (P = 0.004) and pathology types (P = 0.049) were significant prognostic factors for disease-free survival. Pim-3 is a potential predictive biomarker for the response of rectal cancer to chemoradiotherapy.

Neoadjuvant radiochemotherapy decreases the total amount of tumor infiltrating lymphocytes, but increases the number of CD8+/Granzyme B+ (GrzB) cytotoxic T-cells in rectal cancer

Although neoadjuvant radiochemotherapy (nRCTx) is an established oncological treatment in patients with advanced rectal cancer, little is known about its effects on the tumor microenvironment. Quantity and composition of tumor infiltrating lymphocytes (TILs) are known to influence patients' prognosis but nRCTx-induced modifications are still unclear. We determined the composition of the immune cell infiltrate in rectal cancer after nRCTx and its influence on tumor regression, local recurrence rate and survival. We investigated density and composition of tumor infiltrating CD3⁺ and CD8⁺ T-cells and the quantity and ratio of CD8⁺/GrzB⁺ T-cells to CD8⁺ T-cells in 130 rectal cancers after nRCTx compared to a cohort of 30 primarily resected rectal cancers. Furthermore, we analyzed 22 pretherapeutic rectal cancer biopsies, later treated with nRCTx and surgery to evaluate nRCTx-induced modifications of the tumor microenvironment. The total numbers of CD3⁺ and CD8⁺ T-cells in tumor stroma (p < 0.001) and tumor epithelium (p < 0.001 CD3; 0.002 CD8) were significantly lower in rectal cancers after nRCTx compared to primarily resected cases, while the ratio of CD8⁺/GrzB⁺ T-cells to CD8⁺ T-cells was significantly increased in the nRCTx cohort (p < 0.001). In multivariate analyses, CD8⁺/GrzB⁺ T-cells in the tumor stroma were significantly associated with high regression grade and a lower likelihood of local recurrence (p = 0.029). nRCTx modifies the tumor microenvironment of rectal cancer leading to a total decrease of TILs, but a relative increase in CD8⁺/GrzB⁺ T-cells in the tumor stroma. CD8⁺/GrzB⁺ T-cells may contribute to local tumor control and the better outcome.

Current issues of preoperative radio(chemo)therapy and its future evolution in locally advanced rectal cancer

Neoadjuvant therapies are effective for local control and tumor downstaging. Up to date, preoperative long-course chemoradiotherapy and short-course radiotherapy are the two primary guideline-recommended neoadjuvant therapies for locally advanced rectal cancer patients. However, clinicians throughout the world are trying their best to further optimize the regimens and concepts of neoadjuvants. Hence, there is an urgent need to summarize evidence regarding indications of neaoadjuvant therapies and relative merits of current standard regimens. In addition, we also reviewed the optimized regimens mainly based on short-course radiotherapy with delayed surgery, consolidation chemotherapy, induction chemotherapy, chemotherapy alone without radiation and concepts in terms of organ preservation and personalized treatments to further explore the future evolution of neoadjuvant therapies in rectal cancer.

Clinical and Prognostic Significance of Pathological and Inflammatory Markers in Mucinous Rectal Cancer Patients Receiving Neoadjuvant Chemoradiotherapy and Curative Surgery

Background

The aim of this study was to investigate the clinical and prognostic significance of pathological and inflammatory marker in mucinous rectal cancer patients receiving neoadjuvant chemoradiotherapy and curative surgery.

Material/Methods

We retrospectively evaluated the patient records of mucinous rectal cancer patients receiving neoadjuvant chemoradiotherapy and curative surgery at Liaoning Cancer Hospital and Institute from January 2006 to December 2013. The relationship between overall survival (OS) and clinicopathologic variables, pretreatment neutrophil-to-lymphocyte ratio (NLR), pretreatment platelet-to-lymphocyte ratio (PLR), pretreatment lymphocyte-to-monocyte ratio (LMR), and other biomarkers were analyzed by using Kaplan-Meier analysis and log-rank testing. Subsequently a Cox proportional hazard model was used to calculate hazard ratios for the risk of death.

Results

A total of 100 mucinous rectal cancer patients were included for analysis during the study period. The median age at presentation was 60.5 years (range, 26–81 years). The median overall survival (OS) for the whole group was 94 months. On univariate analysis, time interval from CCRT to operation (HR 0.37, p=0.03), lymphovascular invasion (HR 3.23, p=0.009), pretreatment NLR (HR 3.87, p=0.012), and LMR (HR 0.31, p=0.002) were significant prognostic factors for OS. In a multivariate analysis, pretreatment LMR was found to be an independent prognostic factor for overall survival (HR, 0.43; 95%CI, 0.18 to 1.00, p=0.045).

Conclusions

Pretreatment lymphocyte-to-monocyte ratio is a useful prognostic marker of OS in patients with mucinous rectal carcinoma treated with neoadjuvant chemoradiotherapy and curative surgery.

Rectal Carcinoma: Demographics and Clinicopathological Features from Pakistani Population Perspective

Background

Colorectal carcinoma is ranked as the second most common cancer diagnosis in females and third in males. It is the third leading cause of cancer-related deaths worldwide. Disease burden has been attributed to a myriad of factors comprising genetic, environmental, and dietary factors. Rectal cancer has been shown to demonstrate variance according to the geographical location.

Methods

A retrospective review of 477 rectal cancer patients treated at Shaukat Khanum Memorial Cancer Hospital & Research Centre from 2006 to 2014 was performed. Demographic and clinicopathological features were compared between the two age groups (≤40 or >40 years). These included sex, ethnicity, family history of cancer, the location of tumor, clinical staging, histopathological type, and response to chemoradiation. Chi-square was used to compare the frequencies between the two age groups. p-value < 0.05 was taken as significant.

Results

Mean age of the study group was 44.62 ± 16.11 years. 43.8% were ≤40 years of age, and 70.2% were male. 50.3% patients belong to Punjab province, 287 (60.2%) had lower rectal cancer, family history of cancer was present in 82 (17.2%) patients. 432 (90.5%) patients had T1/T2 disease and 296 (62.1%) had N2 disease. Metastatic disease at presentation was observed in 37 (7.8%). Progressive disease was found in 90 (18%) patients.

Conclusion

High frequency of young onset rectal cancers and the lack of family history emphasize the need of indigenous strategies and national awareness of this disease for an early identification of these patients.

Prognosis and value of preoperative radiotherapy in locally advanced rectal signet-ring cell carcinoma

As well known, signet-ring cell carcinoma (SRCC) is a rare histological subtype of colorectal adenocarcinoma, which has been associated with poor prognosis and resistant to non-surgery therapy compared with common adenocarcinoma. In this study, we assessed the effect of preoperative radiotherapy (PRT) for locally advanced rectal SRCC in a large patient group from the Surveillance, Epidemiology, and End Results program (SEER, 1988–2011) database. SRCC was found in 0.9% (n = 622) rectal cancer (RC) patients in our study. In the PRT setting, SRCC had significantly worse cancer-specific survival than mucinous adenocarcinoma and nonmucinous adenocarcinoma patients (log-rank, P < 0.001). In terms of SRCC, stage III RC patients benefited from PRT (log-rank, P < 0.001) while stage II did not (P = 0.095). The multivariate Cox proportional hazard model showed that PRT was an independent benefit factor in stage III rectal SRCC patients (HR, 0.611; 95% CI, 0.407–0.919; P = 0.018). In conclusion, SRCC was an independent predictor of poor prognosis in stage III RC patients, but not in stage II. In the PRT setting of locally advanced RC, SRCC patients had significantly worse prognosis. PRT was an independent prognostic factor associated with improved survival in stage III rectal SRCC.