Total Neoadjuvant Therapy: A Shifting Paradigm in Locally Advanced Rectal Cancer Management

Adding Boost to Standard Neoadjuvant Radiation for Rectal Cancer Improves Likelihood of Complete Response

BACKGROUND

Pathologic tumor response is a prognostic factor for survival in patients with rectal cancer. Standard neoadjuvant radiation (nRT) dosing for locally advanced rectal cancer ranges from 4500 to 5400 centigray (cGy), but it is unknown if tumor regression differs as a consequence adding a boost to the tumor bed.

METHODS

The National Cancer Database (NCDB) 2006-2016 was used to identify patients 18 years of age and older with clinical stage II and III rectal cancer who received pelvic nRT dosed between 4500 and 5400 cGy. Standard nRT dose (no boost, NB) and dose with boost (DWB) were defined respectively as 4500 and 5040-5400 cGy. Complete pathologic response (pCR) was defined as postoperative pathologic stage of zero. A multivariate logistic regression was performed to evaluate the association between radiation dosing and pCR.

RESULTS

The study cohort was 28,841 patients; the majority received DWB 22,701 (78.7%), while 6140 (21.3%) received NB. pCR was achieved in 3135 (14.4%) patients. On multivariate analysis, patients who received NB were significantly less likely to have complete tumor response (OR 1.41, 95% CI 1.2-1.66, p < 0.001). Other factors significantly associated with pCR included insurance, facility type, tumor characteristics, clinical stage, and time between radiation and surgery.

CONCLUSIONS

This is the first investigation demonstrating that standard dose neoadjuvant radiation for rectal cancer was associated with a lower likelihood of pCR compared with standard dose with boost. Past studies demonstrate that rectal cancer patient survival is strongly correlated with pCR. Prospective trials should focus on examining neoadjuvant radiation dosing to evaluate if DWB improves outcomes.

Harnessing the potential of multimodal radiotherapy in prostate cancer

Radiotherapy in combination with androgen deprivation therapy (ADT) is a standard treatment option for men with localized and locally advanced prostate cancer. However, emerging clinical evidence suggests that radiotherapy can be incorporated into multimodality therapy regimens beyond ADT, in combinations that include chemotherapy, radiosensitizing agents, immunotherapy and surgery for the treatment of men with localized and locally advanced prostate cancer, and those with oligometastatic disease, in whom the low metastatic burden in particular might be treatable with these combinations. This multimodal approach is increasingly recognized as offering considerable clinical benefit, such as increased antitumour effects and improved survival. Thus, radiotherapy is becoming a key component of multimodal therapy for many stages of prostate cancer, particularly oligometastatic disease.

Adjuvant Chemotherapy Use in Patients With Locally Advanced Rectal Cancer: A Single-Institution Experience

BACKGROUND

National Comprehensive Cancer Network guidelines for the treatment of locally advanced rectal cancer advocate neoadjuvant chemoradiotherapy followed by total mesorectal excision and adjuvant chemotherapy (AC). The aim of this retrospective study was to determine our local patterns of AC use and to examine factors that influenced initiation and completion of AC among patients with stage II/III rectal cancer.

PATIENTS AND METHODS

The study population consisted of stage II/III rectal cancer patients who were treated at the University of Rochester from 2011 to 2014. Chart reviews were conducted to determine rates of AC initiation and completion. The documented reasons for failure to initiate or complete AC were examined. A multivariate analysis was also completed to evaluate factors that may have influenced the initiation and use of AC.

RESULTS

Eighty-one patients were included in the analysis. Median age was 62 years, and 53 (65.4%) were male. Median time from surgery to initiation of AC in those who received AC was 8.0 weeks. Forty-seven patients (58.0%) completed their prescribed AC course. Twenty-four patients (29.6%) did not start AC and 9 patients (11.1%) were unable to complete their course of AC. Primary reasons for not undergoing AC were patient preference (37.5%) and prolonged surgical recovery (33.3%). Primary reasons for not completing AC were treatment toxicities (55.5%) and patient preference (22.2%). Multivariate analysis identified a positive association between clinical stage III disease at diagnosis and initiation of AC. There was no independent association between pathologic response to neoadjuvant therapy at time of surgery and receipt of AC.

CONCLUSION

A large proportion of patients at a single academic center did not start or complete their prescribed postoperative AC for locally advanced rectal cancer. Ongoing studies are investigating a total neoadjuvant approach, which may result in better chemotherapy adherence and further improve the pathologic downstaging rate.

Long noncoding RNA LINC00461 mediates cisplatin resistance of rectal cancer via miR-593-5p/CCND1 axis

On account of the acquired drug resistance, the potency of cisplatin-based chemotherapy is far from satisfactory in rectal cancer. Increasing evidence has highlighted the crucial function of aberrantly expressed lncRNAs on the cisplatin resistance in multiple cancers. This research was the first attempt to decipher the underlying function and mechanism of long intergenic non-protein coding RNA 461 (LINC00461) in rectal cancer and also its relation to cisplatin resistance of rectal cancer. Data from this study revealed that LINC00461 expression was upregulated in rectal cancer cells. LINC00461 depletion restrained rectal cancer progression and sensitized rectal cancer cells to cisplatin. Molecular mechanism assays testified that LINC00461 bound with miR-593-5p. Besides, miR-593-5p upregulation improved the sensitivity of rectal cancer cells to cisplatin. Additionally, cyclin D1 (CCND1) was manifested to be a downstream target of miR-593-5p. Furthermore, CCND1 upregulation could reverse the effect of LINC00461 downregulation on rectal cancer progression and cisplatin resistance of rectal cancer. To sum up, LINC00461 mediates cisplatin resistance of rectal cancer by targeting miR-593-5p/CCND1 axis, shedding new light on the treatment of rectal cancer.

Disparities in neoadjuvant radiation dosing for treatment of rectal cancer

BACKGROUND

Certain patients are less likely to undergo appropriate cancer treatment, worsening their overall cancer survival. The purpose of this investigation was to identify factors associated with inadequate neoadjuvant radiation for rectal cancer.

METHODS

The National Cancer Database was queried for patients with locally advanced rectal cancer who received neoadjuvant radiation 2006-2014. Adequate radiation was considered to be 4,500-5,040 cGy. Demographic, hospital and clinical variables were analyzed for association with inadequate radiation.

RESULTS

The study cohort was 34,391 patients; 1,842(5.4%) received inadequate radiation. On multivariate analysis, female gender, older age, other race, government-provided insurance, lower clinical stage and rural location correlated with inadequate radiation.

CONCLUSIONS

Women were 50% less likely than men to receive correct neoadjuvant radiation dosing. Other factors including age, race, insurance, clinical stage, geographic location and neoadjuvant chemotherapy were significantly associated with radiation dosing. These factors should be evaluated to determine if they can be modified to improve outcomes.

[Selection criteria for neoadjuvant chemoradiotherapy of rectal cancer : Neoadjuvant therapy even for locally advanced colon cancer?]

During the last two decades a neoadjuvant treatment concept has been established for an increasing number of malignant tumors of the gastrointestinal tract; however, these concepts are still subject to a constant change concerning the indications and type of treatment. A prime example for this is rectal cancer. The rate of local recurrence in particular was significantly reduced by neoadjuvant therapy but until now it has not been possible to validly show an improvement in overall or disease-free survival. At the beginning of the millennium it was recommended to treat every rectal carcinoma in UICC stages II and III with neoadjuvant therapy, independent of the height localization. In the meantime this has increasingly been relativized and only locally advanced tumors of the middle and lower thirds of the rectum should be pretreated, whereas tumors of the upper third of the rectum should basically be treated in the same way as colon cancer. It is to be expected that there will be further differentiation concerning the indications in this context in the future mainly based on a preoperative magnetic resonance imaging (MRI) examination. At the same time, initial studies for colon cancer show that neoadjuvant chemotherapy can be beneficial and that an optimized computed tomography (CT) scan can be a worthwhile tool with respect to pretherapeutic stratification of patients.

Predicting prognosis according to preoperative chemotherapy response in patients with locally advanced lower rectal cancer

BACKGROUND

Neoadjuvant chemoradiotherapy is regarded as the standard of treatment for locally advanced lower rectal cancer, although some of these cases are systemic, and distant control may be inadequate. Neoadjuvant chemotherapy could compensate for such shortcomings, potentially yielding better survival outcomes. We aimed to stratify patients into prognostic groups on the basis of preoperative factors, including response to neoadjuvant chemotherapy.

METHODS

We retrospectively analyzed patients with locally advanced lower rectal adenocarcinoma (clinical stage II/III with high-risk features of distant metastasis) who were treated with neoadjuvant chemotherapy (without radiotherapy) followed by curative resection between 2010 and 2017. Reduction in tumor volume (before vs. after neoadjuvant chemotherapy) was measured using magnetic resonance imaging, and a reduction above 60% was defined as a good response. Recurrence and overall survival were evaluated.

RESULTS

The cohort comprised 102 patients. Good response to neoadjuvant chemotherapy was associated with better 5-year recurrence-free survival (good responders: 81.1%, poor responders: 49.0%; p = 0.001) and 5-year overall survival (good responders: 94.9%, poor responders: 80.6%; p = 0.06). In a multivariate analysis, extramural venous invasion on magnetic resonance imaging after neoadjuvant chemotherapy and a tumor volume reduction rate < 60 were found to be significantly and independently associated with worse recurrence-free survival (hazard ratio: 2.74, 95% confidence interval: 1.36-5.50, p = 0.005 and hazard ratio: 3.48, 95% confidence interval: 1.57-7.72, p = 0.002, respectively). Good responders without extramural venous invasion had the best 5-year recurrence-free and overall survival (89.0 and 93.8%, respectively). Poor responders with extramural venous invasion had the worst 5-year recurrence-free and overall survival (21.4 and 50.0%, respectively).

CONCLUSIONS

Reductions in tumor volume after neoadjuvant chemotherapy were associated with a better prognosis in patients with locally advanced lower rectal cancer. Extramural venous invasion was a preoperative prognostic factor.

High expression of microRNA-199a-5p is associated with superior clinical outcomes in patients with locally advanced rectal cancer

PURPOSE

We aimed to identify biomarkers of response to preoperative CRT in patients with LARC using comprehensive miRNA analysis.

METHODS

This study included 65 rectal cancer specimens and 89 serum samples from patients diagnosed with LARC and treated with preoperative. All specimens were collected before CRT for evaluation of biologic differences between the good and poor CRT response groups (ypStage 0/I versus II/III/IV). For specific miRNA discovery, 800 miRNAs in 20 rectal cancer specimens were analyzed with a NanoString assay. For validation, a total of 65 tissue and 89 serum samples were tested with reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS

In the discovery set, 16 target miRNAs were detected. In the validation set, higher expression of three miRNAs (miR-199a/b-3p, miR-199a-5p, and miR-199b-5p) was significantly associated with better response to CRT. In the univariate survival analysis, upregulation of these three miRNAs was associated with superior relapse-free survival (RFS) and overall survival (OS). Meanwhile, only a higher level of tissue miR-199a-5p was associated with superior RFS [hazard ratio (HR), 0.0.91; 95% confidence interval (CI) 0.035-0.580; p = 0.002] and OS (HR, 0.272; 95% CI 0.023-0.658; p < 0.001) in the multivariate survival analysis. Also, a higher level of exosomal miR-199b-5p correlated with better response to CRT (p = 0.0397).

CONCLUSION

High expression of tissue miR-199a/b-3p, miR-199a-5p, and miR-199b-5p was significantly associated with response to CRT, and a high level of tissue miR-199a-5p was associated with superior survival outcomes. Also, upregulated exosomal miR-199b-5p correlated with CRT response, reflecting its promise as a circulating biomarker of CRT response in patients with LARC.

LncRNA PART1 regulates colorectal cancer via targeting miR-150-5p/miR-520h/CTNNB1 and activating Wnt/β-catenin pathway

Numerous studies have reported that lncRNAs could play a significant role in carcinogenesis. PART1, as an identified lncRNA, was an oncogene in several cancers. However, the underling mechanism of PART1 regulating colorectal cancer remains unknown. qRT-PCR was used to measure relevant RNAs expression. CCK8 and colony formation were combined to evaluate cell proliferation. Tunel and flow cytometry were performed to access cell apoptosis. Wound healing and Transwell assay testified cell invasion and migration ability. Relevant protein expression level was measured via Western blot assay. TOP/FOP luciferase assay determined the activity of Wnt/β-catenin pathway. According to experiment findings, PART1 was up-regulated in CRC tissues and cell lines. Inhibition of PART1 hindered CRC cell proliferation, invasion and migration, while promoting CRC cell apoptosis. Experiments in vivo also validated this result. Mechanistically, PART1 sponged miR-150-5p/miR-520 h to up-regulate CTNNB1, thus activating Wnt/β-catenin pathway in CRC. In summary, PART1 could up-regulate CTNNB1 via sponging miR-150-5p/miR-520 h.

National Cancer Institute (NCI) state of the science: Targeted radiosensitizers in colorectal cancer

Colorectal cancer (CRC) represents a major public health problem as the second leading cause of cancer-related mortality in the United States. Of an estimated 140,000 newly diagnosed CRC cases in 2018, roughly one-third of these patients will have a primary tumor located in the distal large bowel or rectum. The current standard-of-care approach includes curative-intent surgery, often after preoperative (neoadjuvant) radiotherapy (RT), to increase rates of tumor down-staging, clinical and pathologic response, as well as improving surgical resection quality. However, despite advancements in surgical techniques, as well as sharpened precision of dosimetry offered by contemporary RT delivery platforms, the oncology community continues to face challenges related to disease relapse. Ongoing investigations are aimed at testing novel radiosensitizing agents and treatments that might exploit the systemic antitumor effects of RT using immunotherapies. If successful, these treatments may usher in a new curative paradigm for rectal cancers, such that surgical interventions may be avoided. Importantly, this disease offers an opportunity to correlate matched paired biopsies, radiographic response, and molecular mechanisms of treatment sensitivity and resistance with clinical outcomes. Herein, the authors highlight the available evidence from preclinical models and early-phase studies, with an emphasis on promising developmental therapeutics undergoing prospective validation in larger scale clinical trials. This review by the National Cancer Institute's Radiation Research Program Colorectal Cancer Working Group provides an updated, comprehensive examination of the continuously evolving state of the science regarding radiosensitizer drug development in the curative treatment of CRC.

Molecular and Kinetic Analyses of Circulating Tumor Cells as Predictive Markers of Treatment Response in Locally Advanced Rectal Cancer Patients

Neoadjuvant chemoradiation (NCRT) followed by total mesorectal excision is the standard treatment for locally advanced rectal cancer (LARC). To justify a non-surgical approach, identification of pathologic complete response (pCR) is required. Analysis of circulating tumor cells (CTCs) can be used to evaluate pCR. We hypothesize that monitoring of thymidylate synthase (TYMS) and excision repair protein, RAD23 homolog B (RAD23B), can be used to predict resistance to chemotherapy/radiotherapy. Therefore, the aims of this study were to analyze CTCs from patients with LARC who underwent NCRT plus surgery for expression of TYMS/RAD23B and to evaluate their predictive value. Blood samples from 30 patients were collected prior to NCRT (S1) and prior to surgery (S2). CTCs were isolated and quantified by ISET^®, proteins were analyzed by immunocytochemistry, and TYMS mRNA was detected by chromogenic in situ hybridization. CTC counts decreased between S1 and S2 in patients exhibiting pCR (p = 0.02) or partial response (p = 0.01). Regarding protein expression, TYMS was absent in 100% of CTCs from patients with pCR (p = 0.001) yet was expressed in 83% of non-responders at S2 (p < 0.001). Meanwhile, RAD23B was expressed in CTCs from 75% of non-responders at S1 (p = 0.01) and in 100% of non-responders at S2 (p = 0.001). Surprisingly, 100% of non-responders expressed TYMS mRNA at both timepoints (p = 0.001). In addition, TYMS/RAD23B was not detected in the CTCs of patients exhibiting pCR (p = 0.001). We found 83.3% of sensitivity for TYMS mRNA at S1 (p = 0.001) and 100% for TYMS (p = 0.064) and RAD23B (p = 0.01) protein expression at S2. Thus, TYMS mRNA and/or TYMS/RAD23B expression in CTCs, as well as CTC kinetics, have the potential to predict non-response to NCRT and avoid unnecessary radical surgery for LARC patients with pCR.

Randomized Phase II Trial of Chemoradiotherapy Plus Induction or Consolidation Chemotherapy as Total Neoadjuvant Therapy for Locally Advanced Rectal Cancer: CAO/ARO/AIO-12

PURPOSE

Total neoadjuvant therapy is a new paradigm for rectal cancer treatment. Optimal scheduling of preoperative chemoradiotherapy (CRT) and chemotherapy remains to be established.

PATIENTS AND METHODS

We conducted a multicenter, randomized, phase II trial using a pick-the-winner design on the basis of the hypothesis of an increased pathologic complete response (pCR) of 25% after total neoadjuvant therapy compared with standard 15% after preoperative CRT. Patients with stage II or III rectal cancer were assigned to group A for induction chemotherapy using three cycles of fluorouracil, leucovorin, and oxaliplatin before fluorouracil/oxaliplatin CRT (50.4 Gy) or to group B for consolidation chemotherapy after CRT. Secondary end points included toxicity, compliance, and surgical morbidity.

RESULTS

Of the 311 patients enrolled, 306 patients were evaluable (156 in group A and 150 in group B). CRT-related grade 3 or 4 toxicity was lower (37% v 27%) and compliance with CRT higher in group B (91%, 78%, and 76% v 97%, 87%, and 93% received full-dose radiotherapy, concomitant fluorouracil, and concomitant oxaliplatin in groups A and B, respectively); 92% versus 85% completed all induction/consolidation chemotherapy cycles, respectively. The longer interval between completion of CRT and surgery in group B (median 90 v 45 days in group A) did not increase surgical morbidity. A pCR in the intention-to-treat population was achieved in 17% in group A and in 25% in group B. Thus, only group B (P < .001), but not group A (P = .210), fulfilled the predefined statistical hypothesis.

CONCLUSION

Up-front CRT followed by chemotherapy resulted in better compliance with CRT but worse compliance with chemotherapy compared with group A. Long-term follow-up will assess whether improved pCR in group B translates to better oncologic outcome.

Cost-Effectiveness Analysis of Total Neoadjuvant Therapy Followed by Radical Resection Versus Conventional Therapy for Locally Advanced Rectal Cancer

BACKGROUND

Definitive surgery with total mesorectal excision is the mainstay of treatment for locally advanced rectal cancer. Multimodality therapy improves long-term survival. Current standards advise neoadjuvant chemoradiation followed by radical surgery and adjuvant chemotherapy. Nationally, compliance with adjuvant chemotherapy is only 32%. New research evaluates the effectiveness of total neoadjuvant therapy: complete chemotherapy and chemoradiation before surgery.

OBJECTIVE

The aim of this study is to determine the favored treatment for locally advanced rectal cancer by comparing the cost-effectiveness of total neoadjuvant therapy and the current standard of care.

DESIGN

Decision analytical modeling using long-term costs and 5-year disease-free survival was performed to determine the cost-effectiveness after total neoadjuvant therapy and the current standard of care. Sensitivity analysis was used to investigate the effect of uncertainty in model parameters.

SETTINGS

Centers for Medicare & Medicaid Services billing data perspective was adopted and outcomes modeled according to local and national databases and literature consensus.

PATIENTS

Adult patients with stage II or III rectal cancer were selected.

MAIN OUTCOME MEASURES

Cost-effectiveness in disease-free life-years, incremental cost-effectiveness ratio, and net monetary benefit were determined over a 5-year posttreatment period. The favored strategy was determined based on cost-effectiveness and sensitivity analyses.

RESULTS

Cost-effectiveness for total neoadjuvant therapy was 40,708 $/life-year, and, for conventional therapy, cost-effectiveness was 44,248 $/life-year. Sensitivity analysis showed that, for an estimated total neoadjuvant therapy completion rate of 90%, total neoadjuvant therapy would remain the dominant strategy for any adjuvant chemotherapy completion rate of less than 93%.

LIMITATIONS

The samples used to calculate completion rates are small, and survival probabilities are based on existing literature, local database values, and consensus estimates. The model encompasses a 5-year time period from diagnosis.

CONCLUSIONS

Cost-effectiveness analysis shows that a strategy of total neoadjuvant therapy followed by radical surgery is favored over the current standard of care for locally advanced rectal cancer. Sensitivity analysis shows that a low rate of adjuvant chemotherapy administration plays a key role in decreasing the cost-effectiveness of the current standard of care. See Video Abstract at http://links.lww.com/DCR/A942.

Long non-coding RNA IQCJ-SCHIP1 antisense RNA 1 is downregulated in colorectal cancer and inhibits cell proliferation

Background

IQCJ-SCHIP1 antisense RNA 1 (IQCJ-SCHIP1-AS1) was a functional novel long non-coding RNA (lncRNA) revealed by our previous expression profile. In this study, we aim to investigate its clinical relevance and biological significance in colorectal cancer (CRC).

Methods

We measured the expression levels of IQCJ-SCHIP1-AS1 in 86 paired CRC tissues using quantitative RT-PCR assay, and then analyzed its association with patient prognoses. Moreover, gain-of-function and loss-of-function studies were performed to examine the biological functions of IQCJ-SCHIP1-AS1. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) and gene set enrichment analysis (GSEA) were used to elucidate potential mechanisms of IQCJ-SCHIP1-AS1 in CRC.

Results

More than 2-fold decreased expression of IQCJ-SCHIP1-AS1 was found in half of CRC tissues (53.5%, 46/86). IQCJ-SCHIP1-AS1 down-regulation was correlated with poor differentiation (P=0.025), advanced depth of tumor (P=0.022), lymphatic invasion (P=0.010), advanced tumor stage (P=0.006), and poor prognosis (P=0.0027) in CRC patients. The Cox proportional hazards model demonstrated that IQCJ-SCHIP1-AS1 expression was an independent prognostic factor for CRC (HR =0.247, 95% CI: 0.081-0.752, P=0.014). Moreover, knockdown of IQCJ-SCHIP1-AS1 promoted CRC cell proliferation through increasing cell cycle progression and impairing cell apoptosis. Additionally, bioinformatics analysis showed that differential expression genes in IQCJ-SCHIP1-AS1-depleted CRC cells were enriched in the pathways of cell cycle, DNA replication, and p53.

Conclusions

Our results demonstrate that IQCJ-SCHIP1-AS1 has an indicative tumor suppressor role and appears to be a potential prognostic factor in CRC for the first time.

An experimental strategy unveiling exosomal microRNAs 486-5p, 181a-5p and 30d-5p from hypoxic tumour cells as circulating indicators of high-risk rectal cancer

Tumour hypoxia contributes to poor treatment outcome in locally advanced rectal cancer (LARC) and circulating extracellular vesicles (EVs) as potential biomarkers of tumour hypoxia and adverse prognosis have not been fully explored. We examined EV miRNAs from hypoxic colorectal cancer cell lines as template for relevant miRNAs in LARC patients participating in a prospective biomarker study (NCT01816607). Five cell lines were cultured under normoxia (21% O₂) or hypoxia (0.2% O₂) for 24 h, and exosomes were isolated by differential ultracentrifugation. Using a commercial kit, exosomes were precipitated from 24 patient plasma samples collected at the time of diagnosis. Exosome size distribution and protein cargo were determined by cryo-electron microscopy, nanoparticle tracking analysis, immunoblotting and flow cytometry. The vesicles harboured strong cell line-specific miRNA profiles with 35 unique miRNAs differentially expressed between hypoxic and normoxic cells. Six of these miRNAs were considered candidate-circulating markers of tumour hypoxia in the patients based on the frequency or magnitude of variance in hypoxic versus normoxic cell line experiments and prevalence in patient plasma. Of these, low plasma levels of exosomal miR-486-5p and miR-181a-5p were associated with organ-invasive primary tumour (p = 0.029) and lymph node metastases (p = 0.024), respectively, both attributes of adverse LARC prognosis. In line with this, the plasma level of exosomal miR-30d-5p was elevated in patients who experienced metastatic progression (p = 0.036). Our strategy confirmed that EVs from colorectal cancer cell lines were exosomes containing the oxygen-sensitive miRNAs 486-5p, 181a-5p and 30d-5p, which were retrieved as circulating markers of high-risk LARC.

Neoadjuvant chemoradiation and rectal cancer

Neoadjuvant chemoradiation (NACR) is now standard of care in stage II and III rectal cancer. The advent of this modality of treatment has impacted on the way the pathological evaluation of resection specimens that have been subjected to preoperative chemoradiation is conducted. The gross description, sectioning and microscopic examination have had to be adapted to accommodate the changes induced by NACR. Attempts at introducing a uniform approach to the gross triaging and reporting of these specimens have been met with muted response. There still exists much variation in approach. The purpose of this overview is to highlight some of the newer developments and issues around NACR-treated rectal cancers from a pathological point of view. The NACR-treated resection specimens should be handled in a consistent manner, at least within individual institutions, if not universally. There should be generous sampling with multiple sections taken as tumour is often sequestered deep in the bowel wall. Microscopic examination should be extra vigilant as residual cancer can be present as single cells or small clusters, often deep in the muscularis propria or serosa. Acellular pools of mucin or non-viable tumour cells in mucin within the bowel wall or lymph nodes are not regarded as positive and do not upstage the tumour. The issue of grading of regression has been the subject of much debate, and several approaches have been published. It is recommended that a system that has clinical meaning and use to oncologists be used. Lymph node counts will be reduced after NACR, but reasonable attempts to accrue 12 nodes should be made.

Novelties in treatment of locally advanced rectal cancer

Treatment of locally advanced rectal cancer is evolving through surgical innovation and paradigm shifts in neoadjuvant treatment. Whereas local recurrence was a significant concern before the systematic implementation of neoadjuvant chemoradiation therapy and surgery according to total mesorectal excision principles, distant relapse remains a major drawback. Hence, efforts in recent years have focused on delivering preoperative chemotherapy regimens to overcome compliance issues with adjuvant administration. In parallel, new surgical techniques, including transanal video-assisted total mesorectal excision and robot-assisted surgery, emerged to face the challenge to navigate in the deep and narrow spaces of the pelvis. Furthermore, patients experiencing a complete response after neoadjuvant treatment might even escape surgery within a close surveillance strategy. This novel "watch and wait" concept has gained interest to improve quality of life in highly selected patients. This review summarizes recent evidence and controversies and provides an overview on timely and innovative aspects in the treatment of locally advanced rectal cancer.

Is it Possible to Successfully Treat Locally Advanced Colon Cancer Using Pre-Operative Chemoradiotherapy?

Pre-operative chemoradiotherapy (CRT) is a preferable treatment option for patients with locally advanced rectal cancer. However, few data are available regarding pre-operative CRT for locally advanced colon cancer. Here, we describe two cases of successful treatment with pre-operative CRT and establish evidence supporting this treatment option in patients with locally advanced colon cancer. In the first case, a 65-year-old woman was diagnosed with ascending colon cancer with duodenal invasion. In the second case, a 63-year-old man was diagnosed with a colonic-duodenal fistula due to transverse colon cancer invasion. These case reports will help to establish a treatment consensus for pre-operative CRT in patients with locally advanced colon cancer.

Systematic review of treatment intensification using novel agents for chemoradiotherapy in rectal cancer

BACKGROUND

With the well established shift to neoadjuvant treatment for locally advanced rectal cancer, there is increasing focus on the use of radiosensitizers to improve the efficacy and tolerability of radiotherapy. There currently exist few randomized data exploring novel radiosensitizers to improve response and it is unclear what the clinical endpoints of such trials should be.

METHODS

A qualitative systematic review was performed according to the PRISMA guidelines using preset search criteria across the PubMed, Cochrane and Scopus databases from 1990 to 2017. Additional results were generated from the reference lists of included papers.

RESULTS

A total of 123 papers were identified, of which 37 were included; a further 60 articles were obtained from additional referencing to give a total of 97 articles. Neoadjuvant radiosensitization for locally advanced rectal cancer using fluoropyrimidine-based chemotherapy remains the standard of treatment. The oral derivative capecitabine has practical advantages over 5-fluorouracil, with equal efficacy, but the addition of a second chemotherapeutic agent has yet to show a consistent significant efficacy benefit in randomized clinical assessment. Preclinical and early-phase trials are progressing with promising novel agents, such as small molecular inhibitors and nanoparticles.

CONCLUSION

Despite extensive research and promising preclinical studies, a definite further agent in addition to fluoropyrimidines that consistently improves response rate has yet to be found.

LncRNA NKILA correlates with the malignant status and serves as a tumor-suppressive role in rectal cancer

NF-κB interacting lncRNA (NKILA) has been found to function as a tumor-suppressive role in various human cancers. However, the role of NKILA in rectal cancer is still unknown. The objective of this study is to investigate the clinical value and biological function of NKILA in rectal cancer. The association between NKILA expression and clinical variables including prognosis was estimated in rectal cancer patients. The gain-of-function study of NKILA in rectal cancer cell was conducted to evaluate the effect of NKILA on cell proliferation, migration, invasion, and NF-κB signaling pathway. The results suggested NKILA expression was decreased in rectal cancer tissues and cells, and correlated with clinical stage, T classification, N classification and M classification. NKILA low-expression was an independent poor prognostic factor in rectal cancer patients. NKILA-inhibited rectal cancer cell proliferation, migration, and invasion via suppressing NF-κB signaling. In conclusion, NKILA serves as an antioncogenic lncRNA in rectal cancer.

Trans-perineal minimally invasive surgery during laparoscopic abdominoperineal resection for low rectal cancer

BACKGROUND

Laparoscopic abdominoperineal resection (APR) for low rectal cancer (LRC) is performed worldwide. However, APR involves technical difficulties and often causes intractable perineal complications. Therefore, a novel and secure technique during APR is required to overcome these critical issues. Although the usefulness of the endoscopic trans-anal approach has been documented, no series of the endoscopic trans-perineal approach during laparoscopic APR for LRC has been reported.

METHODS

Trans-perineal minimally invasive surgery (TpMIS) has been used during laparoscopic APR in our institution since April 2014. TpMIS is defined as an endoscopic trans-perineal approach using a single-port device and laparoscopic instruments. In this study, we retrospectively evaluated 50 consecutive patients with LRC who underwent laparoscopic APR at our institution from February 2011 to June 2017 and compared the outcomes of the patients who underwent TpMIS [trans-perineal APR (TpAPR) group, n = 21] versus the conventional trans-perineal approach (conventional group, n = 29). We investigated our experiences with TpMIS in detail and evaluated the safety and utility of TpMIS for patients with LRC. Moreover, major features and difficulties of TpMIS were examined from a surgical viewpoint.

RESULTS

Intraoperative blood loss (median (range) 55 (10-600) vs. 120 (20-1650) ml) and severe perineal wound infection (Clavien-Dindo grade 3, 0 vs. 5 cases) were significantly lower in the TpAPR than conventional group. TpMIS led to a shortened hospital stay (median (range), 14 (10-74) vs. 23 (10-84) days), and neither mortality nor conversion to open surgery occurred in the TpAPR group.

CONCLUSIONS

Magnified visualization via endoscopy provided more accurate dissection and less blood loss during surgery. Minimal skin incisions enabled a reduction in postoperative perineal complications, and consequently shortened the hospital stay. TpMIS during laparoscopic APR is safe and beneficial for patients with LRC.