Total Neoadjuvant Therapy in Locally Advanced Rectal Cancer: A Systematic Review and Metaanalysis of Oncological and Operative Outcomes.

BACKGROUND: Total neoadjuvant therapy in rectal cancer refers to the administration of chemoradiotherapy plus chemotherapy before surgery. Recent studies have shown improved pathological complete response and disease-free survival with this approach. However, survival benefits remain unproven. Our objective is to present a metaanalysis of oncological outcomes of total neoadjuvant therapy in locally advanced rectal cancer. PATIENTS AND METHODS: A comprehensive search was performed on PubMed, Medline, and Google Scholars. Studies comparing total neoadjuvant therapy with standard neoadjuvant chemoradiotherapy were included. Data extracted from the individual studies were pooled and a metaanalysis performed. The outcomes of interest are the rate of complete pathological response, nodal response, resection margin, anal preservation, anastomotic leak, local recurrence, distant recurrence, disease-free survival, and overall survival. RESULTS: There were 15 comparative studies with 2437 patients in the neoadjuvant chemoradiotherapy group and 2284 in the total neoadjuvant therapy group. The pooled complete pathological response was 22.3% in the total neoadjuvant therapy group, compared with 14.2% in the standard neoadjuvant chemoradiotherapy group (p < 0.001). Even though there was no difference in local recurrence rate, there was a significantly lower rate of distant recurrence (OR 0.81, p = 0.02), and better 3-year disease-free survival (70.6% vs. 65.3%, respectively, p < 0.001) and overall survival (84.9% vs. 82.3%, respectively, p = 0.006), favoring the total neoadjuvant therapy group. Due to significant heterogeneity in the study protocols, there remains uncertainty on the ideal chemotherapy/radiotherapy sequence. CONCLUSIONS: This study provides supporting evidence on the favorable immediate and intermediate oncological outcomes with the use of total neoadjuvant therapy for locally advanced rectal cancer.

Is neoadjuvant therapy an alternative strategy to immediate surgery in locally perforated colon cancer?

BACKGROUND: Perforations are a rare but serious complication of colorectal cancer. The current standard of treatment is emergent surgery followed by adjuvant chemotherapy. The concern with this approach is not only the uncertainty of achieving a R0 resection but also potential injury to adjacent vessels, nerves and ureters due to inflamed tissue planes. A subset of this patient population with a contained perforation who are clinically stable may have superior oncological outcomes with local sepsis control, neoadjuvant therapy followed by radical resection. The aim of this study is to report on the pre-operative safety profile for neoadjuvant therapy in the setting of an abscess from colon cancer perforation and the short-term oncological surgical quality outcomes. METHODS: In this retrospective observational study, all consecutive perforated colon cancer receiving neoadjuvant therapy from Jan 2010 to Dec 2019 were included. RESULTS: There were 21 patients that met the inclusion criteria. The most common symptom at presentation was abdominal pain (71.4%) and most common site of perforation was sigmoid colon (61.9%). Local sepsis control was achieved with a combination of radiological or surgical drainage, diverting ostomy and/or intravenous antibiotics. Thirteen patients had long-course chemoradiation and eight patients had neoadjuvant chemotherapy. Of these, 13 (61.9%) had tumour regression, with one patient having a pathological complete response. All patients achieved a R0 resection. CONCLUSIONS: In a small subset of patients with colon cancer perforation, this study has demonstrated the potential safe usage of neoadjuvant therapy first before radical surgery to achieve a clear resection margin.

Cutaneous leiomyosarcoma: dermal and subcutaneous.

BACKGROUND AND OBJECTIVES: Leiomyosarcoma of skin (LMS) can be sub-classified on pathology appearances as Dermal or Subcutaneous. The aim of this study was to provide treatment recommendations for these uncommon tumours. METHODS: A retrospective review of all patients with dermal and subcutaneous leiomyosarcoma managed at the Peter MacCallum Cancer Centre, Australia from January 2003 to December 2018 was performed. Eighty-three patients were identified (64 dermal leiomyosarcoma, 19 subcutaneous leiomyosarcoma). RESULTS: Subcutaneous leiomyosarcoma were larger (median size 14 mm dermal, 49 mm subcutaneous, P = 0.01). No patient with a dermal leiomyosarcoma developed metastatic disease compared to 4 of the 19 subcutaneous leiomyosarcoma (5-year overall survivals, 98% and 88%, respectively, P = 0.03). The most common site of metastasis was to the lung. No difference in risk of local recurrence was apparent (5-year recurrence-free survivals were 85% and 78%, respectively, P = 0.17). Adjuvant radiotherapy was used in 16 (25%) dermal leiomyosarcoma patients and 13 (68%) subcutaneous leiomyosarcoma patients (P < 0.001). Local recurrence was uncommon in both tumour subtypes when patients received definitive surgical excision (minimum histological margins of 10 mm as per institutional protocol) regardless of whether radiotherapy was used. The 5-year local recurrence-free survival for dermal leiomyosarcoma treated with radiotherapy was 93% versus 83% without radiotherapy (P = 0.7) and for subcutaneous leiomyosarcoma was 69% and 100%, respectively (P = 0.9). CONCLUSIONS: Dermal leiomyosarcoma have an excellent prognosis, particularly after definitive surgical excision with margins of at least 10 mm. Subcutaneous leiomyosarcoma has poorer outcomes and should be managed by wider excision and considered for adjuvant radiotherapy.

Salvage Surgery for Locoregional Failure in Anal Squamous Cell Carcinoma.

BACKGROUND: Anal squamous cell carcinoma is a rare cancer with a high cure rate, making research into the treatment of locoregional failure difficult. OBJECTIVE: The purpose of this study was to examine factors related to local treatment failure and determine the outcomes of patients undergoing local salvage resection. DESIGN: This was a retrospective cohort study. SETTING: This study was conducted at a quaternary referral center. PATIENTS: Patients with anal squamous cell carcinoma treated with chemoradiotherapy between January 1983 and December 2015 were included. MAIN OUTCOME MEASURES: The influence of patient-, tumor-, and treatment-related factors on the primary outcome measures of locoregional failure, overall survival, and disease-free survival were investigated. RESULTS: Of 467 patients with anal squamous cell carcinoma, 63 experienced locoregional failure with 41 undergoing salvage resection. Twenty-seven patients (38%) had persistent disease and 36 (62%) developed locoregional recurrence. Multivariate analysis identified tumor stage (HR, 3.16; p < 0.002) as an independent predictor of locoregional failure. Thirty abdominoperineal resections and 11 pelvic exenterations were undertaken with no surgical mortality. At a median follow-up of 20 months (range, 4-150 months), 5-year overall and disease-free survival for the salvage cohort was 51% and 47%. Margin positivity was an independent predictor for relapse post-salvage surgery on multivariate analysis (HR, 20.1; p = 0.027). Nineteen patients (48%) developed further relapse, which included all 10 patients with a positive resection margin, 3 of whom underwent re-resection. Of the 19 patients with relapse, 3 remain alive and 2 have persistent disease. LIMITATIONS: Limitations include the retrospective nature of the database, the prolonged time period of the study, and episodes of incomplete data. CONCLUSIONS: Advanced T stage is an independent predictor of local failure in anal squamous cell carcinoma. Most patients can be salvaged, with a positive resection margin being a strong predictor of further relapse and poor outcome. See Video Abstract at http://links.lww.com/DCR/A515.

Outcomes and prognostic factors of multimodality treatment for locally recurrent rectal cancer with curative intent.

PURPOSE: Radical management of locally recurrent rectal cancer (LRRC) can lead to prolonged survival. This study aims to assess outcomes and identify prognostic factors for patients with LRRC treated using a multimodality treatment protocol. METHODS: An analysis of a prospectively maintained institutional database of consecutive patients who underwent radical surgical resection for LRRC was performed. Potential prognostic factors were investigated using a Cox proportional hazards model. RESULTS: Ninety-eight patients were included in this study. A multimodality approach was taken in the majority, including preoperative chemoradiation (78%), intraoperative radiation therapy (47%) and adjuvant chemotherapy (41%). Extended resection was performed where required: bone resection (34%) and lateral pelvic sidewall dissection (31%). The rate of R0 resection was 66%. Estimated rates of 5-year overall survival (OS) and progression-free survival (PFS) were 41.8% (95% CI 32.5-53.7) and 22.5% (95% CI 15.3-33.1). On multivariate analysis, stage III disease at initial primary surgery, a positive margin at initial primary surgery, synchronous or previously resected oligometastases, a lateral or sacral invasive-type pelvic recurrence and the requirement for IORT all predicted for inferior PFS (p < 0.05). Eleven percent of patients subsequently underwent further pelvic surgery for pelvic re-recurrence and had an estimated 5-year OS rate of 54.5% (95% CI 29.0-100.0) from repeat surgery. CONCLUSIONS: Radical multimodality management of LRRC leads to prolonged survival in approximately 40% of patients. Those with sacral or lateral invasive-type recurrence or oligometastatic disease have inferior outcomes and further research is needed to optimise treatment for these groups.

Acute Adverse Events and Postoperative Complications in a Randomized Trial of Preoperative Short-course Radiotherapy Versus Long-course Chemoradiotherapy for T3 Adenocarcinoma of the Rectum: Trans-Tasman Radiation Oncology Group Trial (TROG 01.04).

OBJECTIVE: To compare acute adverse events (AE) and postoperative complication rates in a randomized trial of short-course (SC) versus long-course (LC) preoperative radiotherapy. BACKGROUND: Evidence demonstrates that adding neoadjuvant radiotherapy to surgery offers better local control in the management of rectal cancer. With both SC and LC therapy there is a potential for acute treatment-related toxicity and increased patient morbidity. METHODS: Eligible patients had clinical-stage T3 rectal adenocarcinoma within 12 cm of the anal verge with no evidence of metastasis. SC consisted of pelvic radiotherapy 5 × 5 Gy in 1 week, early surgery and 6 courses of adjuvant chemotherapy. LC was 50.4 Gy administered in 28 fractions during 5.5 weeks, with infusion 5-fluorouracil, surgery in 4 to 6 weeks, and 4 courses of chemotherapy. RESULTS: All SC patients and 93% of LC patients received preoperative planned radiotherapy. There was no 30-day operative mortality. A statistically significant higher percentage of at least 1 AE occurred in the LC group (SC, 72.3%; LC, 99.4%; P < 0.001). There were significant differences in favor of SC for grade 3 AE: radiation dermatitis (0% vs 5.6%, P = 0.003), proctitis (0% vs 3.7% P = 0.016), nausea (0% vs 3.1%, P = 0.029), fatigue (0% vs 3.7%, P = 0.016) and grade 3/4 diarrhea rates (1.3% vs 14.2% P < 0.001). No statistically significant differences in surgical complication rates were seen (SC 53.2 vs 50.4% LC, p = 0.68), although permanent stoma (38.0% vs 29.8%, P = 0.13) and anastomotic breakdown (7.1% vs 3.5%, P = 0.26) rates favored LC with perineal wound complications (38.3% vs 50.0%, P = 0.26) in favor of SC. CONCLUSIONS: LC had significantly higher AEs compared with SC with no statistically significant differences in postoperative complications. There were clinical trends in permanent stoma rates and anastomotic leaks in favor of LC but with an increased perineal wound breakdown rate.

Relative Value of Restaging MRI, CT, and FDG-PET Scan After Preoperative Chemoradiation for Rectal Cancer.

BACKGROUND: Management of rectal cancer has become multidisciplinary and is driven by the stage of the disease, with increased focus on restaging rectal cancer after neoadjuvant therapy. OBJECTIVE: The purpose of this study was to assess the relative impact of restaging after preoperative chemoradiation with FDG-PET scan, CT, and MRI in the management of patients with rectal cancer. DESIGN: This was a retrospective study from a single institution. SETTINGS: This study was conducted at a tertiary cancer center. PATIENTS: A total of 199 patients met the inclusion criteria: patients with rectal adenocarcinoma; staged with positron emission tomography, CT, and MRI; T2 to T4, N0 to N2, M0 to M1; treated with neoadjuvant chemoradiation 50.4 Gy and infusional 5-fluorouracil; and restaged 4 weeks after chemoradiation before surgery between 2003 and 2013. MAIN OUTCOME MEASURES: Comparisons of the tumor stage among different imaging modalities before and after neoadjuvant chemoradiation were performed. The impact of restaging on the management plan was assessed. RESULTS: The stage at presentation was T2, 8.04%; T3, 65.33%; T4, 26.63%; N0, 17.09%; N1, 47.74%; N2, 34.67%; M0, 81.91%; and M1, 18.09%. Changes in disease stage postneoadjuvant chemoradiation were observed in 99 patients (50%). The management plans of 29 patients (15%) were changed. The impact of each restaging modality on management for all of the patients was positron emission tomography, 11%; CT, 4%; and MRI, 4%. In patients with metastatic disease at primary staging, the relative impact of each restaging modality in changing management was positron emission tomography, 32%; CT, 18%; and MRI, 6%. LIMITATIONS: This study was limited by its single-center and retrospective design. Operations were performed 4 weeks after restaging. CONCLUSIONS: Changes in the extent of disease after long-course chemoradiotherapy result in changes of management in a significant percentage of patients. Positron emission tomography has the most significant impact in the change of management overall, and its use in restaging advanced rectal cancer should be further explored.

Molecular biology of anal squamous cell carcinoma: implications for future research and clinical intervention.

Anal squamous cell carcinoma is a human papillomavirus-related disease, in which no substantial advances in treatment have been made in over 40 years, especially for those patients who develop disease relapse and for whom no surgical options exist. HPV can evade the immune system and its role in disease progression can be exploited in novel immunotherapy platforms. Although several studies have investigated the expression and inactivation (through loss of heterozygosity) of tumour suppressor genes in the pathways to cancer, no clinically valuable biomarkers have emerged. Regulators of apoptosis, including survivin, and agents targeting the PI3K/AKT pathway, offer opportunities for targeted therapy, although robust data are scarce. Additionally, antibody therapy targeting EGFR may prove effective, although its safety profile in combination with standard chemoradiotherapy has proven to be suboptimal. Finally, progress in the treatment of anal cancer has remained stagnant due to a lack of preclinical models, including cell lines and mouse models. In this Review, we discuss the molecular biology of anal squamous cell carcinoma, clinical trials in progress, and implications for novel therapeutic targets. Future work should focus on preclinical models to provide a resource for investigation of new molecular pathways and for testing novel targets.

Systematic review of FDG-PET prediction of complete pathological response and survival in rectal cancer.

BACKGROUND: Advances in the management of rectal cancer have resulted in an increased application of multimodal therapy with the aim of tailoring therapy to individual patients. Complete pathological response (pCR) is associated with improved survival and may be potentially managed without radical surgical resection. Over the last decade, there has been increasing interest in the ability of functional imaging to predict complete response to treatment. The aim of this review was to assess the role of (18)F-flurordeoxyglucose positron emission tomography (FDG-PET) in prediction of pCR and prognosis in resectable locally advanced rectal cancer. METHODS: A search of the MEDLINE and Embase databases was conducted, and a systematic review of the literature investigating positron emission tomography (PET) in the prediction of pCR and survival in rectal cancer was performed. RESULTS: Seventeen series assessing PET prediction of pCR were included in the review. Seven series assessed postchemoradiation SUVmax, which was significantly different between response groups in all six studies that assessed this. Nine series assessed the response index (RI) for SUVmax, which was significantly different between response groups in seven series. Thirteen studies investigated PET response for prediction of survival. Metabolic complete response assessed by SUV2max or visual response and RISUVmax showed strong associations with disease-free survival (DFS) and overall survival (OS). CONCLUSION: SUV2max and RISUVmax appear to be useful FDG-PET markers for prediction of pCR and these parameters also show strong associations with DFS and OS. FDG-PET may have a role in outcome prediction in patients with advanced rectal cancer.

Impact of advancing age on treatment and outcomes in anal cancer.

BACKGROUND: Chemoradiotherapy (CRT) for squamous cell carcinoma of the anus (SCCA) may cause significant toxicity, and concerns exist about its tolerability in the elderly. The authors compared tolerability and outcomes across the age groups following CRT for SCCA. METHODS: Single-institution retrospective analysis of patients with localized SCCA treated with CRT. CRT was standardized at 50.4-54 Gy, with concurrent infusional 5-fluorouracil and mitomycin C. Patients were arbitrarily categorized into three groups: Group 1 - age < 50 years; Group 2 - age ≥ 50 and < 70 years; and Group 3 - age ≥ 70 years. RESULTS: Of 284 patients identified, 278 were evaluable. The number of patients in each age group was: Group 1 - 51; Group 2 - 140; and Group 3 - 93. Baseline and treatment characteristics, tumor stage, rates of overall acute toxicity, need for unplanned treatment breaks and chemotherapy delivery were largely similar across the age groups. However, nine patients in Group 3 did not complete CRT, compared with five and none in Groups 1 and 2, respectively (p = 0.006). In addition, five patients in Group 3 had diarrhea requiring treatment break, compared with none in the other two groups (p = 0.004). At a median follow-up 5.3 years, there was no significant difference in overall survival (p = 0.11), disease-free survival (p = 0.22) or local-recurrence free survival (p = 0.34), across the three age groups. CONCLUSIONS: CRT is safe and tolerable in the elderly age group, and provides equivalent disease control rates compared with the younger age group. Age alone should therefore not preclude aggressive curative treatment.

Partially Ablative Body Radiotherapy (PABR): A novel approach for palliative radiotherapy of locally advanced bulky unresectable sarcomas.

BACKGROUND: Locally advanced, bulky, unresectable sarcomas cause significant tumour mass effects, leading to burdensome symptoms. We have developed a novel Partially Ablative Body Radiotherapy (PABR) technique that delivers a high, ablative dose to the tumour core and a low, palliative dose to its periphery aiming to increase overall tumour response without significantly increasing treatment toxicity. AIM: This study aims to report the safety and oncologic outcomes of PABR in patients with bulky, unresectable sarcomas. METHODS AND MATERIALS: A total of 18 patients with histologically proven sarcoma treated with PABR from January 2020 to October 2023 were retrospectively reviewed. The primary endpoints were symptomatic and structural response rates. Secondary endpoints were overall survival, freedom from local progression, freedom from distant progression, and acute and late toxicity rates. RESULTS: All patients had tumours ≥5 cm with a median tumour volume of 985 cc, and the most common symptom was pain. The median age is 72.5 years and 44.5 % were ECOG 2-3. The most common regimen used was 20 Gy in 5 fractions with an intratumoral boost dose of 50 Gy (83.3 %). After a median follow-up of 11 months, 88.9 % of patients exhibited a partial response with a mean absolute tumour volume reduction of 49.5 %. All symptomatic patients experienced symptom improvement. One-year OS, FFLP and FFDP were 61 %, 83.3 % and 34.8 %, respectively. There were no grade 3 or higher toxicities. CONCLUSION: PABR for bulky, unresectable sarcomas appears to be safe and may provide good symptomatic response, tumour debulking, and local control. Further study is underway.

Intensification of Local Therapy With High Dose Rate, Intraoperative Radiation Therapy (HDR-IORT) and Extended Resection for Locally Advanced and Recurrent Colorectal Cancer.

BACKGROUND: We report our long-term experience with high dose rate intraoperative radiotherapy (HDR-IORT) in a single, quaternary institution. PATIENTS/METHODS: From 2004 to 2020, 60 HDR-IORT procedures for locally advanced colorectal cancer (LACC) and 81 for locally recurrent colorectal cancer (LRCC) were done in our institution. Preoperative radiotherapy was done prior to majority of the resections (89%, 125/141). Sixty-nine percent (58/84) of the resections involving pelvic exenterations had >3 en bloc organs resected. HDR-IORT was delivered using a Freiburg applicator. A single 10 Gy fraction was delivered. Margin status was R0 and R1 in 54% (76/141) and 46% (65/141) of the resections, respectively. RESULTS: With a median follow-up time of 4 years, 3-, 5-, and 7- year, overall survival (OS) rates were 84%, 58%, and 58% for LACC and 68%, 41%, and 37% for LRCC, respectively. Local progression-free survival (LPFS) rates were 97%, 93%, and 93% for LACC and 80%, 80%, 80% for LRCC, respectively. For the LRCC group, an R1 resection was associated with worse OS, LPFS, and progression-free survival (PFS), preoperative EBRT was associated with improved LPFS and PFS, and ≥2 years disease-free interval was associated with improved PFS. The most common severe adverse events were postoperative abscess (n = 25) and bowel obstruction (n = 11). There were 68 grade 3 to 4 and no grade 5 adverse events. CONCLUSIONS: Favorable OS and LPFS can be achieved for LACC and LRCC with intensive local therapy. In patients with risk factors for poorer outcomes, optimization of EBRT and IORT, surgical resection, and systemic therapy are required.

pCR and 2-Year Disease-Free Survival: A Combination of the Two Endpoints as a New Classification for Locally Advanced Rectal Cancer Patients-An Updated Pooled Analysis of Eleven International Randomized Trials.

LARC is managed by multimodal treatments whose intensity can be highly modulated. In this context, we need surrogate endpoints to help predict long-term outcomes and better personalize treatments. A previous study identified 2yDFS as a stronger predictor of OS than pCR in LARC patients undergoing neoadjuvant RT. The aim of this pooled analysis was to assess the role of pCR and 2yDFS as surrogate endpoints for OS in a larger cohort. The pooled and subgroup analyses were performed on large rectal cancer randomized trial cohorts who received long-course RT. Our analysis focused on the evaluation of OS in relation to the pCR and 2-year disease status. A total of 4600 patients were analyzed. Four groups were identified according to intermediate outcomes: 12% had both pCR and 2yDFS (the better); 67% achieved 2yDFS but not pCR (the good); 1% had pCR but not 2yDFS; and 20% had neither pCR nor 2yDFS (the bad). The pCR and 2yDFS were favorably associated with OS in the univariate analysis, and 2yDFS maintained a statistically significant association in the multivariate analysis independently of the pCR status. The combination of the pCR and 2yDFS results in a strong predictor of OS, whereas failure to achieve 2yDFS carries a poor prognosis regardless of the pCR status. This new stratification of LARC patients could help design predictive models where the combination of 2yDFS and pCR should be employed as the primary outcome.

Current State of Neoadjuvant Radiotherapy for Rectal Cancer.

Colorectal cancer is the third most commonly diagnosed cancer, with rectal cancer accounting for 30% of cases. The current standard of care curative treatment for locally advanced rectal cancer is (chemo)radiotherapy followed by surgery and adjuvant chemotherapy. Although neoadjuvant radiotherapy has reduced the risk of local recurrence to less than 10%, the risk of distant metastasis remained high at 30% affecting patient survival. In addition, there is a recognition that there is heterogeneity in tumor biology and treatment response with good responders potentially suitable for treatment de-escalation. Therefore, new treatment sequencing and regimens were investigated. Here, we reviewed the evidence for current neoadjuvant treatment options in patients with locally advanced rectal adenocarcinoma, and highlight the new challenges in this new treatment landscape.

Long-term Patterns of Failure and the Value of Blood Prognostic Markers in Anal Cancers Treated With Intensity-Modulated Radiation Therapy.

BACKGROUND: To analyze the long-term outcomes and prognostic value of hematological parameters in anal cancer patients receiving intensity-modulated radiation therapy (IMRT). MATERIALS: Hospital records of consecutive patients with anal squamous cell carcinoma who received curative-intent IMRT according to a standardized contouring protocol between 2010 and 2020 were reviewed. Locoregional failure-free survival (LRFS), distant metastasis-free survival (DMFS), progression-free survival (PFS), and overall survival (OS) were estimated using the Kaplan-Meier method. Coverage of locoregional recurrences by the initial IMRT volumes were assessed. The prognostic value of pretreatment blood counts for PFS and OS were determined using Cox regression analysis. RESULTS: A total of 166 patients were analyzed with a median follow-up of 3.3 years. Forty-six percent and 54% of patients had Stage I-II and IIIA-B cancers, respectively. The 5-year LRFS, DMFS, PFS and OS were 81%, 89%, 65% and 76% respectively. Grade ≥ 3 toxicity occurred in 5% of patients. Of all patients who relapsed, 70% had only locoregional recurrence as first site of failure. Ninety percent of locoregional recurrences were in-field. Hemoglobin, neutrophil and platelet counts were associated with PFS on univariable analysis, but only cancer stage and p16 status remained prognostic on multivariable analysis. Patients with more advanced cancer stages also had higher baseline neutrophil counts. Performance status and neutrophil counts were prognostic for OS on multivariable analysis. CONCLUSION: This study affirms the long-term efficacy and safety of IMRT. Treatment resistance, rather than radiation geographic miss, is a major issue underpinning locoregional recurrences. Pretreatment blood counts were not validated to be independently prognostic for disease recurrence.

Bayesian network structure for predicting local tumor recurrence in rectal cancer patients treated with neoadjuvant chemoradiation followed by surgery.

Background and Purpose: Tumor recurrence, a characteristic of malignant tumors, is the biggest concern for rectal cancer survivors. The epidemiology of the disease calls for a pressing need to improve healthcare quality and patient outcomes. Prediction models such as Bayesian networks, which can probabilistically reason under uncertainty, could assist caregivers with patient management. However, some concerns are associated with the standard approaches to developing these structures in medicine. Therefore, this study aims to compare Bayesian network structures that stem from these two techniques. Patients and Methods: A retrospective analysis was performed on 6754 locally advanced rectal cancer (LARC) patients enrolled in 14 international clinical trials. Local tumor recurrence at 2, 3, and 5-years was defined as the endpoints of interest. Five rectal cancer treating physicians from three countries elicited the expert structure. The algorithmic structure was inferred from the data with the hill-climbing algorithm. Structural performance was assessed with calibration plots and area under the curve values. Results: The area under the curve for the expert structure on the training and validation data was above 0.9 and 0.8, respectively, for all the time points. However, the algorithmic structure had superior predictive performance over the expert structure for all time points of interest. Conclusion: We have developed and internally validated a Bayesian networks structure from experts' opinions, which can predict the risk of a LARC patient developing a tumor recurrence at 2, 3, and 5 years. Our result shows that the algorithmic-based structures are more performant and less interpretable than expert-based structures.

The predictive value of PET/CT for distant recurrences in locally advanced rectal cancer treated with neoadjuvant chemoradiotherapy.

INTRODUCTION: It is well recognized that pathological complete response (pCR) for locally advanced rectal cancer after neoadjuvant chemoradiotherapy (CRT) confers a positive survival advantage. Despite this, a small proportion of patients can develop distant recurrence, and these are the patients that will likely benefit from adjuvant therapy. This study aims to investigate the role of PET/CT as a functional imaging to stratify patients according to their risk of distant recurrence. METHODS: This is a retrospective analysis of a prospectively maintained database in a single quaternary teaching hospital from 2010 to 2019. All consecutive cases of locally advanced rectal cancer with restaging PET/CT were included. The primary outcome measure was 5-year OS and distant recurrence-free survival. RESULTS: A pCR and complete metabolic response (CMR) were identified in 47 (18%) patients and 73 (27.4%) patients respectively. Of these, 26 patients had both pCR and CMR and these patients remained free of local and distant recurrence at their last censored date. Patients with both pCR and CMR achieved the highest 5-year overall survival of 96.2%, followed by those with pCR and incomplete CMR (iCMR) of 85.7%, non-pCR and CMR of 85.1% and non-pCR and iCMR of 83.1%. Independent predictors for 5-year distant recurrence-free survival were pathological and PET metabolic response, nodal staging and lymphovascular invasion (LVI). CONCLUSION: In conclusion, a PET/CT has the potential to better stratify patients of their risk of distant metastasis. However, a larger validation cohort is required before these findings can be translated to clinical utility.

Timing to achieve the highest rate of pCR after preoperative radiochemotherapy in rectal cancer: a pooled analysis of 3085 patients from 7 randomized trials.

PURPOSE: Optimal timing of surgery after neoadjuvant chemoradiotherapy (Nad-CRT) is still controversial in locally advanced rectal cancer (LARC). The primary goal of this study was to determine the best surgical interval (SI) to achieve the highest rate of pathological complete response (pCR) and secondly to evaluate the effect on survival outcomes according to the SI. PATIENTS AND METHODS: Patients data were extracted from the international randomized trials: Accord12/0405, EORTC22921, FFCD9203, CAO/ARO/AIO-94, CAO-ARO-AIO-04, INTERACT and TROG01.04. Inclusion criteria were: age≥ 18, cT3-T4 and cN0-2, no clinical evidence of distant metastasis at diagnosis, Nad-CRT followed by surgery. Pearson's Chi-squared test with Yates' continuity correction for categorical variables, the Mann-Whitney test for continuous variables, Mann-Kendall test, Kaplan-Meier curves with log-rank test, univariate and multivariate logistic regression model was used for data analysis. RESULTS: 3085 patients met the inclusion criteria. Overall, the pCR rate was 14% at a median SI of 6 weeks (range 1-31). The cumulative pCR rate increased significantly when SI lengthened, with 95% of pCR events within 10 weeks from Nad-CRT. At univariate and multivariate logistic regression analysis, lengthening of SI (p< 0.01), radiotherapy dose (p< 0.01), and the addition of oxaliplatin to Nad-CRT (p< 0.01) had a favorable impact on pCR. Furthermore, lengthening of SI was not impact on local recurrences, distance metastases, and overall survival. CONCLUSION: This pooled analysis suggests that the best time to achieve pCR in LARC is at 10 weeks, considering that the lengthening of SI is not detrimental concerning survival outcomes.

Results of phase II trial of intensified neoadjuvant treatment with interdigitating radiotherapy and chemotherapy with oxaliplatin, 5-fluorouracil and folinic acid in patients with locally advanced rectal cancer (PROARCT trial).

BACKGROUND AND PURPOSE: The chemotherapy exposure during chemoradiotherapy for rectal cancer is adequate for radiosensitization but suboptimal for treatment of distant micrometastasis. This study aimed to determine tolerability, dose intensity, response, and toxicity of a novel intensified neoadjuvant treatment approach. MATERIALS AND METHODS: Eligible patients were MRI-staged T3-4NxM0 rectal adenocarcinoma. Treatment consisted of FOLFOX chemotherapy given in weeks 1, 6, and 11 with pelvic radiotherapy (25.2 Gy in 3 weeks in 1.8 Gy/fraction with oxaliplatin and 5-FU continuous infusion) given in weeks 3-5, and weeks 8-10. Surgery was performed 4-6 weeks later. The primary endpoint was tolerability defined as the percentage of patients who were able to complete the planned treatment course. Survival rates were estimated using the Kaplan-Meier method. RESULTS: Median age of the 40 patients was 61.5 years. Rectal MRI-stage was T3 in 88%. Overall, 95% completed the regimen. All patients received 50.4 Gy. Relative dose intensity (≥75%) was 92% and 98% for oxaliplatin and 5-FU, respectively. High grade toxicities included neutropenia (25% grade 3; 7.5% grade 4) and diarrhoea (10%). Pathologic CR rate was 20%. Median follow-up was 54 months. The 5-year overall survival, freedom from relapse, locoregional control, and freedom from distant metastasis of the cohort was 82%, 72%, 97% and 72%. CONCLUSIONS: Delivery of intensified neoadjuvant treatment with interdigitating chemotherapy and radiotherapy is feasible with no increase in acute perioperative complications. A larger prospective study is required to further evaluate the potential survival benefit of this design.

Molecular and genomic characterisation of a panel of human anal cancer cell lines.

Anal cancer is a rare disease that has doubled in incidence over the last four decades. Current treatment and survival of patients with this disease has not changed substantially over this period of time, due, in part, to a paucity of preclinical models to assess new therapeutic options. To address this hiatus, we set-out to establish, validate and characterise a panel of human anal squamous cell carcinoma (ASCC) cell lines by employing an explant technique using fresh human ASCC tumour tissue. The panel of five human ASCC cell lines were validated to confirm their origin, squamous features and tumourigenicity, followed by molecular and genomic (whole-exome sequencing) characterisation. This panel recapitulates the genetic and molecular characteristics previously described in ASCC including phosphoinositide-3-kinase (PI3K) mutations in three of the human papillomavirus (HPV) positive lines and TP53 mutations in the HPV negative line. The cell lines demonstrate the ability to form tumouroids and retain their tumourigenic potential upon xenotransplantation, with varied inducible expression of major histocompatibility complex class I (MHC class I) and Programmed cell death ligand 1 (PD-L1). We observed differential responses to standard chemotherapy, radiotherapy and a PI3K specific molecular targeted agent in vitro, which correlated with the clinical response of the patient tumours from which they were derived. We anticipate this novel panel of human ASCC cell lines will form a valuable resource for future studies into the biology and therapeutics of this rare disease.