Accuracy of deep neural learning models in the imaging prediction of pathological complete response after neoadjuvant chemoradiotherapy for locally advanced rectal cancer: a systematic review.

PURPOSE: Up to 15-27% of patients achieve pathologic complete response (pCR) following neoadjuvant chemoradiotherapy (CRT) for locally advanced rectal cancer (LARC). Deep neural learning (DL) algorithms have been suggested to be a useful adjunct to allow accurate prediction of pCR and to identify patients who could potentially avoid surgery. This systematic review aims to interrogate the accuracy of DL algorithms at predicting pCR. METHODS: Embase (PubMed, MEDLINE) databases and Google Scholar were searched to identify eligible English-language studies, with the search concluding in July 2022. Studies reporting on the accuracy of DL models in predicting pCR were selected for review and information pertaining to study characteristics and diagnostic measures was extracted from relevant studies. Risk of bias was evaluated using the Newcastle-Ottawa scale (NOS). RESULTS: Our search yielded 85 potential publications. Nineteen full texts were reviewed, and a total of 12 articles were included in this systematic review. There were six retrospective and six prospective cohort studies. The most common DL algorithm used was the Convolutional Neural Network (CNN). Performance comparison was carried out via single modality comparison. The median performance for each best-performing algorithm was an AUC of 0.845 (range 0.71-0.99) and Accuracy of 0.85 (0.83-0.98). CONCLUSIONS: There is a promising role for DL models in the prediction of pCR following neoadjuvant-CRT for LARC. Further studies are needed to provide a standardised comparison in order to allow for large-scale clinical application. PROPERO REGISTRATION: PROSPERO 2021 CRD42021269904 Available from: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021269904 .

Application of minimally invasive approaches to pelvic exenteration for locally advanced and locally recurrent pelvic malignancy - A narrative review of outcomes in an evolving field.

INTRODUCTION: Minimally invasive surgical techniques are being successfully used to treat locally advanced and recurrent pelvic malignancy of colorectal origin. This review aims to describe the application of minimally invasive approaches to pelvic exenteration and compare current reported surgical outcomes. METHODS AND RESULTS: A literature search was performed of PubMed, Google Scholar and EMBASE for studies on pelvic exenteration with locally advanced or recurrent rectal cancer utilising minimally invasive techniques. A total of 22 studies were reviewed, including four case reports describing novel approaches. DISCUSSION: Laparoscopic, robotic and trans-anal total mesenteric excision (TaTME) aided pelvic exenteration methods have recently demonstrated low post-operative morbidity and mortality trends. Minimally invasive methods also have improved rates of R0 resection in modest cohort studies. Hybrid methods have also been proposed to overcome observed technical difficulties such as the narrow male pelvis and obese habitus. There is still limited data beyond case report and small cohort studies on challenging patient groups such as those with recurrent rectal cancer or bony involvement, as a consequence of patient selection for these novel approaches. CONCLUSION: International, multicentre studies have provided the best opportunity to explore efficacy of these methods on a larger scale. Further research is required into patient selection, safety and long-term outcomes of these approaches within high volume centres practicing beyond the surgical learning curve.

Melbourne colorectal collaboration: a multicentre review of the impact of COVID-19 on colorectal cancer in Melbourne, Australia.

BACKGROUND: As coronavirus (COVID-19) cases continue to rise, healthcare workers have been working overtime to ensure that all patients receive care in a timely manner. Our study aims to identify the impact and outcomes of COVID-19 on colorectal cancers presentations across the five major colorectal units in Melbourne, Australia. METHODS: This is a retrospective study from a prospectively collected database from the binational colorectal cancer audit (BCCA) registry, as well as inpatient records. All patients with colorectal cancer between Pre-COVID-19 period (1 July 2018-2030 June 2019) and COVID-19 period (1 July 2020-2030 June 2021) were compared. Benign pathology and other cancer types were excluded. RESULTS: A total of 1609 patients were included in the study (700 Pre-COVID-19 period, 906 COVID-19 period). During COVID-19 period, there was a higher proportion of emergency surgery (28.1% vs. 19.8%; P < 0.001), a higher nodal (P = 0.024) and metastatic stage (P = 0.018) at presentation, but no increase in the rate of return to operating theatres (P = 0.240), inpatient death (P = 0.019) or 30-day readmission (P = 0.000). There was also no difference in the post-operative surgical complications (P = 0.118). Utility of neoadjuvant therapy did not increase during the pandemic (P = 0.613). CONCLUSION: The heightened measures in the healthcare system ensured CRC patients still received their surgery in a timely fashion. With the current rise in the new strain of COVID-19 (Omicron), we have to continue to come up with new strategies to provide timely access to CRC care.

Latest evidence on the management of early-stage and locally advanced rectal cancer: a narrative review.

Rectal cancer is a challenging disease process to manage, with a rising incidence in young adults. Several clinical advances have been made in the past decade with regards to optimal treatment strategies in early-stage (T1-2, node negative tumours) and locally advanced cancers (T3-4 and/or nodal positivity) utilizing a multimodal approach of surgery, neoadjuvant chemoradiotherapy, and adjuvant chemotherapy, all aiming to optimize oncological outcomes, while minimizing associated morbidity. This narrative review aimed to summarize trial level evidence apropos the management of early and locally advanced rectal cancer. All relevant prospective clinical trials were identified through a computer-assisted search of PubMed, EMBASE, Medline databases between 1990 and 30 June 2021. With regards to early rectal cancer, there is limited trial-level evidence in the literature. Total mesorectal excision (TME) is the current standard of care, but local excision could be considered in select patients with pT1 tumours, or patients with near or complete clinical response to neoadjuvant CRT. As for locally advanced rectal cancer, the current standard of care consists of long-course chemotheradiotherapy or short-course radiotherapy, followed by TME. However, the role of total neoadjuvant therapy is promising, with respect to both oncological outcomes, as well as in reducing toxicity. Both induction and consolidation chemotherapy treatment approaches have been described in literature, with encouraging early results. The optimal management of rectal cancer is constantly evolving. More research is needed to investigate the long-term oncological and functional outcomes following new multimodal therapies in the management of early-stage and locally advanced rectal cancer.

High-dimensional analyses reveal a distinct role of T-cell subsets in the immune microenvironment of gastric cancer.

OBJECTIVES: To facilitate disease prognosis and improve precise immunotherapy of gastric cancer (GC) patients, a comprehensive study integrating immune cellular and molecular analyses on tumor tissues and peripheral blood was performed. METHODS: The association of GC patients' outcomes and the immune context of their tumors was explored using multiplex immunohistochemistry (mIHC) and transcriptome profiling. Potential immune dysfunction mechanism/s in the tumors on the systemic level was further examined using mass cytometry (CyTOF) in complementary peripheral blood from selected patients. GC cohorts with mIHC and gene expression profiling data were also used as validation cohorts. RESULTS: Increased CD4+FOXP3+ T-cell density in the GC tumor correlated with prolonged survival. Interestingly, CD4+FOXP3+ T cells had a close interaction with CD8+ T cells rather than tumor cells. High densities of CD4+FOXP3+ T cells and CD8+ T cells (High-High) independently predicted prolonged patient survival. Furthermore, the interferon-gamma (IFN-γ) gene signature and PDL1 expression were up-regulated in this group. Importantly, a subgroup of genomically stable (GS) tumors and tumors with chromosomal instability (CIN) within this High-High group also had excellent survival. The High-High GS/CIN tumors were coupled with increased frequencies of Tbet+CD4+ T cells and central memory CD4+ T cells in the peripheral blood. CONCLUSION: These novel findings identify the combination of CD8+ T cells and FOXP3+CD4+ T cells as a significant prognostic marker for GC patients, which also could potentially be targeted and applied in the combination therapy with immune checkpoint blockades in precision medicine.