Optimisation of preoperative assessment in patients diagnosed with rectal cancer

Sense and non-sense of imaging in the era of organ preservation for rectal cancer

This review summarizes the current applications and benefits of imaging modalities for organ preservation in the treatment of rectal cancer. The concept of organ preservation in the treatment of rectal cancer has revolutionized the way rectal cancer is managed. Initially, organ preservation was limited to patients with locally advanced rectal cancer who needed neoadjuvant therapy to reduce tumor size before surgery and achieved complete response. However, neoadjuvant therapy is now increasingly utilized for smaller and less aggressive tumors to achieve primary organ preservation. Additionally, more intensive neoadjuvant strategies are employed to improve complete response rates and increase the chances of successful organ preservation. The selection of patients for organ preservation is a critical component of treatment, and imaging techniques such as digital rectal exam, endoscopy, and MRI are commonly used for this purpose. In this review, we provide an overview of what imaging modalities should be chosen and how they can aid in the selection and follow-up of patients undergoing organ-preserving strategies.

Metformin with neoadjuvant chemoradiation to improve pathologic response in rectal cancer: A pilot phase I/II trial

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A prospective pilot phase I/II study on metformin given concurrently with neoadjuvant chemoradiation (CRT) in non-diabetic rectal cancer patients.

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Three patients had a clinical complete response (cCR) and did not have surgical resection.

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Of the 12 patients who underwent surgery, there were two pCRs. For the combined pCR/cCR rate of 33% (95% CI 19–47%), a total of 85 patients will be required to yield a 95% CI with a 10% margin of error.

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These pilot results are encouraging, and will serve to refine the design and conduct of a future phase 2 trial to determine whether adding metformin to CRT improves pCR/cCR rates.

Purpose

Neoadjuvant radiotherapy with or without chemotherapy decreases the risk of local recurrence after surgery for rectal cancer. Emerging data suggest that diabetic patients on metformin may have improved cancer outcome after radiotherapy. A single institutional pilot study was performed to determine if metformin given concurrently with long course chemoradiation (CRT) may improve pathologic complete response (pCR) in non-diabetic rectal cancer patients. The study was designed to construct a confidence interval (CI) for the pCR rate to determine the sample size for a phase 2 trial.

Methods

Non-diabetic patients with biopsy confirmed rectal cancer deemed candidates for long course neoadjuvant CRT were invited to participate. Radiation consisted of 50.4 Gy in 28 daily fractions with concurrent daily capecitabine (825 mg/m² twice daily). Participants self-administered metformin (500 mg of twice daily) 2 weeks prior to, during and for 4 weeks after CRT.

Results

A total of 16 patients were accrued. One patient withdrew from the study. Only grade 1 or 2 adverse events were observed. Three patients had a clinical complete response (cCR) and did not undergo surgery. Of the 12 patients who underwent surgery, there were two pCRs. For the combined pCR/cCR rate of 33% (95% CI 19–47%), a total of 85 patients will be required to yield a 95% CI with a 10% margin of error.

Conclusions

Adding metformin to neoadjuvant CRT for rectal cancer does not appear to enhance toxicities. These results will be used to refine the design and conduct of a future phase 2 trial to determine whether adding metformin to CRT improves pCR/cCR rates.

High-Intensity vs Low-Intensity Knowledge Translation Interventions for Surgeons and Their Association With Process and Outcome Measures Among Patients Undergoing Rectal Cancer Surgery

IMPORTANCE

Surgeon-directed knowledge translation (KT) interventions for rectal cancer surgery are designed to improve patient measures, such as rates of permanent colostomy and in-hospital mortality, and to improve survival.

OBJECTIVE

To evaluate the association of sustained, iterative, integrated KT rectal cancer surgery interventions directed at all surgeons with process and outcome measures among patients undergoing rectal cancer surgery in a geographic region.

DESIGN, SETTING, AND PARTICIPANTS

This quality improvement study used administrative data from patients who underwent rectal cancer surgery from April 1, 2004, to March 31, 2015, in 14 health regions in Ontario, Canada. Follow-up was completed on March 31, 2020.

EXPOSURES

Surgeons in 2 regions were offered intensive KT interventions, including annual workshops, audit and feedback sessions, and, in 1 of the 2 regions, operative demonstrations, from 2006 to 2012 (high-intensity KT group). Surgeons in the remaining 12 regions did not receive these interventions (low-intensity KT group).

MAIN OUTCOMES AND MEASURES

Among patients undergoing rectal cancer surgery, proportions of preoperative pelvic magnetic resonance imaging (MRI), preoperative radiotherapy, and type of surgery were evaluated, as were in-hospital mortality and overall survival. Logistic regression models with an interaction term between group and year were used to assess whether process measures and in-hospital mortality differed between groups over time.

RESULTS

A total of 15 683 patients were included in the analysis (10 052 [64.1%] male; mean [SD] age, 65.9 [12.1] years), of whom 3762 (24.0%) were in the high-intensity group (2459 [65.4%] male; mean [SD] age, 66.4 [12.0] years) and 11 921 (76.0%) were in the low-intensity KT group (7593 [63.7%] male; mean [SD] age, 65.7 [12.1] years). A total of 1624 patients (43.2%) in the high-intensity group and 4774 (40.0%) in the low-intensity KT group underwent preoperative MRI (P < .001); 1321 (35.1%) and 4424 (37.1%), respectively, received preoperative radiotherapy (P = .03); and 967 (25.7%) and 2365 (19.8%), respectively, received permanent stoma (P < .001). In-hospital mortality was 1.6% (59 deaths) in the high-intensity KT group and 2.2% (258 deaths) in the low-intensity KT group (P = .02). Differences remained significant in multivariable models only for permanent stoma (odds ratio [OR], 1.67; 95% CI, 1.24-2.24; P < .001) and in-hospital mortality (OR, 0.67; 95% CI, 0.51-0.87; P = .003). In both groups over time, significant increases in the proportion of patients undergoing preoperative MRI (from 6.3% to 67.1%) and preoperative radiotherapy (from 16.5% to 44.7%) occurred, but there were no significant changes for permanent stoma (25.4% to 25.3% in the high-intensity group and 20.0% to 18.3% in the low-intensity group) and in-hospital mortality (0.8% to 0.8% in the high-intensity group and 2.2% to 1.8% in the low-intensity group). Time trends were similar between groups for measures that did or did not change over time. Patient overall survival was similar between groups (hazard ratio, 1.00; 95% CI, 0.90-1.11; P = .99).

CONCLUSIONS AND RELEVANCE

In this quality improvement study, between-group differences were found in only 2 measures (permanent stoma and in-hospital mortality), but these differences were stable over time. High-intensity KT group interventions were not associated with improved patient measures and outcomes. Proper evaluation of KT or quality improvement interventions may help avoid opportunity costs associated with ineffective strategies.

Quality indicator selection for the Canadian Partnership against Cancer rectal cancer project: A modified Delphi study

AIM

It is well established that (i) magnetic resonance imaging, (ii) multidisciplinary cancer conference (MCCs), (iii) preoperative radiotherapy, (iv) total mesorectal excision surgery and (v) pathological assessment as described by Quirke are key processes necessary for high quality, rectal cancer care. The objective was to select a set of multidisciplinary quality indicators to measure the uptake of these clinical processes in clinical practice.

METHOD

A multidisciplinary panel was convened and a modified two-phase Delphi method was used to select a set of quality indicators. Phase 1 included a literature review with written feedback from the panel. Phase 2 included an in-person workshop with anonymous voting. The selection criteria for the indicators were strength of evidence, ease of capture and usability. Indicators for which ≥90% of the panel members voted 'to keep' were selected as the final set of indicators.

RESULTS

During phase 1, 68 potential indicators were generated from the literature and an additional four indicators were recommended by the panel. During phase 2, these 72 indicators were discussed; 48 indicators met the 90% inclusion threshold and included eight pathology, five radiology, 11 surgical, six radiation oncology and 18 MCC indicators.

CONCLUSION

A modified Delphi method was used to select 48 multidisciplinary quality indicators to specifically measure the uptake of key processes necessary for high quality care of patients with rectal cancer. These quality indicators will be used in future work to identify and address gaps in care in the uptake of these clinical processes.

Watch and wait approach in rectal cancer: Current controversies and future directions

According to the main international clinical guidelines, the recommended treatment for locally-advanced rectal cancer is neoadjuvant chemoradiotherapy followed by surgery. However, doubts have been raised about the appropriate definition of clinical complete response (cCR) after neoadjuvant therapy and the role of surgery in patients who achieve a cCR. Surgical resection is associated with significant morbidity and decreased quality of life (QoL), which is especially relevant given the favourable prognosis in this patient subset. Accordingly, there has been a growing interest in alternative approaches with less morbidity, including the organ-preserving watch and wait strategy, in which surgery is omitted in patients who have achieved a cCR. These patients are managed with a specific follow-up protocol to ensure adequate cancer control, including the early identification of recurrent disease. However, there are several open questions about this strategy, including patient selection, the clinical and radiological criteria to accurately determine cCR, the duration of neoadjuvant treatment, the role of dose intensification (chemotherapy and/or radiotherapy), optimal follow-up protocols, and the future perspectives of this approach. In the present review, we summarize the available evidence on the watch and wait strategy in this clinical scenario, including ongoing clinical trials, QoL in these patients, and the controversies surrounding this treatment approach.

The Canadian Partnership Against Cancer Rectal Cancer Project: Protocol for a Pan-Canadian, Multidisciplinary Quality Improvement Initiative to Optimize the Quality of Rectal Cancer Care

BACKGROUND

Over the last 2 decades, the use of multimodal strategies, including total mesorectal excision (TME) surgery, preoperative chemotherapy, multidisciplinary case conference, pelvic magnetic resonance imaging, and pathologic assessment using Quirke method, has led to significant improvements in oncologic outcomes for patients with rectal cancer. Although the literature supports claims on the effectiveness of these multimodal strategies, the uptake of these multimodal strategies varies considerably among centers, suggesting that the best evidence is not always implemented into clinical practice.

OBJECTIVE

This study aims to perform a quality improvement initiative to (1) identify existing gaps in care for these multimodal strategies and (2) implement knowledge translation (KT) interventions to close these gaps to optimize quality of care for patients with rectal cancer across high-volume centers in Canada.

METHODS

Process indicators for the selected multimodal strategies to optimize rectal cancer care will be selected and prospectively collected for all patients with stages 1 to 3 rectal cancer undergoing TME surgery. KT interventions, including audit and feedback, opinion leaders, and community of practice, will be implemented to increase the uptake of these clinical strategies.

RESULTS

The uptake of the process indicators over time and the effect of the uptake of the process indicators on short- and long-term oncologic outcomes will be evaluated for each multimodal strategy.

CONCLUSIONS

This quality improvement initiative will identify existing gaps in care for the selected multimodal strategies and implement KT interventions to close these gaps. The results of this study will inform further efforts to optimize rectal cancer care.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/15535.

Management of rectal cancer in Canada: an evidence-based comparison of clinical practice guidelines

Background

Rectal cancer requires a multidisciplinary and multimodality treatment approach. Clinical practice guidelines (CPGs) provide a framework for delivering consistent, evidence-based health care. We compared provincial/territorial CPGs across Canada to identify areas of variability and evaluate their quality.

Methods

We retrieved CPGs from Canadian organizations responsible for cancer care oversight and evaluated their quality and developmental methodology using the AGREE-II instrument. Recommendations for diagnostic and staging investigations, treatment by stage, and post-treatment surveillance of stage I–III rectal cancers were abstracted and compared.

Results

We identified 7 sets of CPGs for analysis, varying in content, presentation, quality, and year last updated. Differences were noted in locoregional staging: 4 recommended magnetic resonance imaging over endorectal ultrasonography, 2 recommended either modality, and 3 specified scenarios for one over the other. Recommendations also varied for use of staging computed tomography of the chest versus chest radiography and for surgical management and indications for transanal excision. Recommendations for neoadjuvant therapy in stage II/III disease also differed: 3 guidelines recommended long-course chemoradiation over short-course radiation therapy alone, while 3 others recommended short-course radiation in specific clinical scenarios. Adjuvant chemotherapy for stage II/III disease was uniformly recommended, with variable protocols. The use of proctosigmoidoscopy and interval/duration of endoscopic post-treatment surveillance varied among guidelines.

Conclusion

Canadian CPGs vary in their recommendations for staging, treatment, and surveillance of rectal cancer. Some of these differences reflect areas with limited definitive evidence. Consistent guidelines with uniform implementation across provinces/territories may lead to more equitable care to patients.

Grey areas and evidence gaps in the management of rectal cancer as revealed by comparing recommendations from clinical guidelines

BACKGROUND

While the management of nonmetastatic and oligometastatic rectal cancer has rapidly evolved over the last few decades, many grey areas and highly debated topics remain that foster significant variation in clinical practice. We aimed to identify controversial points and evidence gaps in this disease setting by systematically comparing recommendations from national and international clinical guidelines.

METHODS

Twenty-six clinical questions reflecting practical challenges in the routine management of nonmetastatic and oligometastatic rectal cancer patients were selected. Recommendations from the ESMO, NCCN, JSCCR, Australian and Ontario guidelines were extrapolated and compared using a 4-tier classification system (i.e., identical/very similar, similar, slightly different, different). Overall agreement between guidelines (i.e., substantial/complete disagreement, partial disagreement, partial agreement, substantial/complete agreement) was assessed for each clinical question and compared against the highest level of available evidence by using the χ² statistic test.

RESULTS

Guidelines were in substantial/complete agreement, partial agreement, partial disagreement, and substantial/complete disagreement for 8 (30.8%), 2 (7.7%), 7 (26.9%), and 9 (34.6%) clinical questions, respectively. High level of evidence supported clinical recommendations in 3/10 cases (30%) where guidelines were in agreement and in 10/16 cases (62.5%) where guidelines were in disagreement (χ² = 2.6, p = 0.106). Agreement was frequently reached for questions regarding diagnosis, staging, and radiology/pathology pro-forma reporting, while disagreement characterised most of the treatment-related topics.

CONCLUSIONS

Substantial variation exists across clinical guidelines in the recommendations for the management of nonmetastatic and oligometastatic rectal cancer. This variation is only partly explained by the lack of supporting, high-level evidence.

Nodal staging in the rectal cancer follow-up MRI after chemoradiotherapy: use of morphology, size, and diffusion criteria

AIM

To analyse changes in post-neoadjuvant follow-up magnetic resonance imaging (MRI) staging accuracy for malignant adenopathies in rectal cancer, by comparing size criteria with morphological criteria using high-resolution T2-weighted sequences, as well as variations when adding diffusion-weighted imaging.

METHODS AND MATERIALS

The present study was a cross-sectional study of a database including 46 1.5-T MRI examinations (2011-2016) from patients with biopsy-proven rectal cancer and chemoradiotherapy treatment before surgery. All cases were reviewed by three radiologists individually, who were blinded to any clinical information. The radiologists were experienced in rectal cancer (3-6 years) and evaluated the presence of malignant nodes in each patient. Malignancy was determined using morphological, size (5 mm), and diffusion criteria separately, as well as morphology plus diffusion. Each case was assessed four times: (1) evaluation of morphological criteria; (2) size criteria; (3) evaluation only using diffusion (b-values 50, 400, and 800); and (4) diffusion plus morphological criteria. Histological staging of surgical specimens was the reference standard. Statistical analysis included accuracy (area under the receiver operating characteristic [ROC] curve [AUC]), sensitivity, specificity, and positive/negative predictive values (PPV/NPV) for each radiologist, and group agreement (Fleiss' kappa).

RESULTS

Mean values using morphological criteria were: AUC 0.78, sensitivity 77.7%, specificity 73.8%, PPV 66.1%, NPV 85.2%. Using size criterion: AUC 0.75, sensitivity 62.9%, specificity 83.2%, PPV 74.1%, NPV 80%. Added diffusion yielded no improvement, and yielded worse results by itself.

CONCLUSIONS

Although morphological criteria showed better results in accuracy, sensitivity, and NPV, size criterion yielded the best specificity and PPV. Adding diffusion did not demonstrate a clear advantage over the criteria by themselves. Thus, mixed size-morphology criteria could have the greatest diagnostic value for follow-up N-staging.

Outcomes of patients in the national cancer database treated non-surgically for localized rectal cancer

Background

Some patients undergo a non-operative approach to localized rectal adenocarcinoma either because they decline surgery or because their medical comorbidities preclude surgical intervention. Published studies reporting excellent outcomes with a "wait-and-see" approach have been small and highly-selected. We aimed to analyze survival outcomes and prognostic factors for patients with localized rectal adenocarcinoma in the National Cancer Database (NCDB) undergoing definitive radiation without surgical intervention.

Methods

The NCDB was queried for patients with non-metastatic rectal adenocarcinoma treated with definitive radiotherapy who did not undergo a surgical resection either because the patient refused surgery, surgery was medically contraindicated, or surgery was otherwise unplanned. Patient, tumor and treatment-related characteristics were compared between those treated with 45-50.3 Gray (Gy), 50.4-54 Gy and >54 Gy. Survivals were compared using the Log-Rank test. Univariate and multivariate Cox regression analyses were performed. Survivals were then compared utilizing a robust inverse-probability-weighted regression adjustment method with nearest-neighbor matching.

Results

Eight thousand four hundred and eight patients were included for analysis. After case-matching and adjusting for significant prognostic factors, patients receiving 50.4-54 Gy had a significantly longer median, 1- and 5-year overall survival (OS) (49.4 months, 85.8%, 44.7%) compared with patients receiving 45-50.3 or >54 Gy (37.2 months, 79.2%, 38.4% and 34.2 months, 84.5%, 35.3%, respectively; Log rank P value <0.0001).

Conclusions

In an unselected group of patients treated at NCDB-participating institutions, survival rates with a non-surgical approach to non-metastatic rectal adenocarcinoma are much lower than those reported in well-selected single-institutional studies. Moderate dose escalation from 50.4-54 Gy was associated with better OS compared with doses <50.4 Gy or >54 Gy after adjusting for significant covariant.

Comparison Between Laparoscopic and Open Resection Following Neoadjuvant Chemoradiotherapy for Mid-Low Rectal Cancer Patients: A Meta-Analysis

INTRODUCTION

The optimal approach of resection for mid-low rectal cancer after neoadjuvant chemoradiotherapy (nCRT) is still controversial. The aim of this meta-analysis was to clarify the safety and feasibility of laparoscopic surgery compared with open resection.

MATERIALS AND METHODS

We performed a literature search for studies on PubMed, Embase and Cochrane Library up to March 1, 2018. Review Manager software was applied for data analysis. We used weighted mean difference (WMD) for continuous parameters and odds ratio (OR) for dichotomous variables. Confidence interval (CI) was set at 95% and a P value <.05 was considered statistically significant.

RESULTS

A total of seven studies met the inclusion criteria for the meta-analysis: 466 patients in laparoscopic group and 491 in open group. The pooled result revealed that laparoscopic resection had a favorable blood loss (WMD = -116.88 mL; 95% CI: -189.78 to -43.99; P = .002), analogous lymph nodes harvest (WMD = -0.30; 95% CI: -1.29 to 0.70; P = .56), less postoperative complications (OR = 0.63; 95% CI: 0.46-0.88; P = .006), shorter time to pass first flatus (WMD = -0.76 day; 95% CI: -1.00 to -0.51; P < .00001), and stay in hospital (WMD = -2.71 days; 95% CI: -4.54 to -0.88; P = .004), despite similar operating time (WMD = 11.17 minutes; 95% CI: -14.37 to 36.70; P = .39).

CONCLUSIONS

Laparoscopic resection might be a technically safe and feasible approach for mid-low rectal cancer patients after nCRT compared with open resection.

Utilization of short-course radiation therapy for patients with nonmetastatic rectal adenocarcinoma in the United States

Purpose

Preoperative short-course radiation therapy (SCRT) for patients with nonmetastatic rectal adenocarcinoma has been studied in European trials, but is not often used in the United States. We aim to describe the utilization of preoperative SCRT among patients with nonmetastatic rectal cancer in the National Cancer Database and describe factors associated with its use.

Methods and materials

The National Cancer Database was queried for patients treated with preoperative radiation therapy followed by surgery for nonmetastatic rectal adenocarcinoma between 2004 and 2014. Patient, tumor, and treatment-related characteristics were compared between patients treated with SCRT (20-25 Gy in <7 fractions) and patients treated with long-course radiation therapy (45-70 Gy in ≥ 25 fractions). Univariate and multivariate Cox regression analyses were used to evaluate factors associated with overall survival. Survival rates were compared using an inverse-probability-weighted regression adjustment method.

Results

A total of 42,336 patients were included for analysis of which 41,867 patients (98.9%) were treated with long-course radiation therapy and 469 patients (1.1%) with SCRT. Patients treated with SCRT were older, had more comorbidities, had earlier T-stage, and were more likely to be clinically node-negative. Patients treated with SCRT were more likely to be treated at an academic center, have Medicare insurance, and be treated without chemotherapy. Patients treated with SCRT had lower pathological complete response rates (4.3% vs 6.9%; P < .001) and higher rates of positive circumferential resection margins (8.3% vs 5.2%; P = .001). On multivariate analysis, radiation fractionation was not significantly associated with overall survival.

Conclusions

SCRT is used for only approximately 1% of patients treated preoperatively for nonmetastatic rectal cancer in the United States. The results of recently completed randomized trials may further inform patterns of practice in the United States and abroad.

Transanal total mesorectal excision (taTME) in a single-surgeon setting: refinements of the technique during the learning phase

BACKGROUND

Transanal total mesorectal excision (taTME) is a safe and effective technique. We have progressively developed a systematic approach in the single-surgeon setting. The aim of this study was to compare our early vs late single-surgeon taTME experience as well as present the technical and logistical modifications that were crucial to achieve successful implementation of a taTME program.

METHODS

Review of prospectively collected data on 27 patients who had taTME in June 2015-September 2016 (early cohort) was included and compared with 43 patients who underwent taTME in October 2016-September 2017 (late cohort). Procedures were performed by a single-surgeon team at Health Sciences North (Sudbury, Ontario, Canada). Inclusion criteria were T1-3 or downstaged T4 mid- and low-rectal lesions. Cases of non-neoplastic disease were excluded. Outcomes assessed included mesorectal integrity, margin status, operative time, complications, morbidity, length of stay and 30-day readmission.

RESULTS

A total of 70 cases were included. Patients were divided into early (27 patients, 14 males; mean age 60.74 ± 9.77 years) and late (43 patients, 29 males; mean age 63.48 ± 10.85 years) cohorts. During the early phase, procedural modifications including regular takedown of the splenic flexure, intra-corporeal division of the mesentery, liberal use of a Pfannenstiel incision for extraction, abundant washing of the surgical field and regular use of the ICG technology were progressively introduced. There was no mortality nor statistically significant difference between the early and late cohort in terms of morbidity (33.3 vs 39.4% p = 0.727), anastomotic leak (14.8 vs 4.6% p = 0.19), operating time (5.05 ± 1.26 vs 4.96 ± 1.14 h p = 0.755), length of stay (4.0 ± 2.54 vs 4.81 ± 3.63 days p = 0.394) and CRM negative margin (96.3 vs. 97.7% p = 0.999), and no incomplete specimens were obtained on either cohort.

CONCLUSIONS

This study confirms the safety and effectiveness of single-surgeon implementation of taTME technique. Technical challenges experienced in this setting were not obstacles for further refinement and to establish a tendency towards better outcomes. Overcoming technical challenges is possible, familiarity with taTME is slow yet progressive, and improvement tends to occur with experience.

The effect of prone and supine treatment positions for the pre-operative treatment of rectal cancer on organ-at-risk sparing and setup reproducibility using volumetric modulated arc therapy

Background and purpose

To compare organ-at-risk doses and setup reproducibility using the prone and supine orientations in volumetric modulated arc therapy (VMAT) for rectal cancer.

Materials and methods

Seventeen consecutive rectal cancer patients undergoing preoperative radiation were selected and setup in either the prone (N = 8) or supine (N = 9) position. All patients were treated using posteriorly-applied VMAT. Bladder and small bowel dose and cone beam CT (CBCT) reproducibility metrics were retrospectively collected.

Results

Dose metrics for bladder and small bowel did not show significant differences between the prone and supine orientations. The prone data had a trend for smaller irradiated volumes than supine for the small bowel at lower doses—V20 (prone: 135 ± 99 cm³; supine: 201 ± 162 cm³) and V30 (prone: 78 ± 71 cm³; supine: 105 ± 106 cm³). At higher doses, the trend reversed as exemplified by the small bowel V50.4 (prone: 20 ± 28 cm³; supine: 10 ± 14 cm³). CBCT data showed that rotational errors in pitch and roll were significantly larger for the prone vs. supine orientation (pitch: 2.0° ± 1.3° vs. 0.8° ± 1.1° p < 0.001; roll: 1.0° ± 0.9° vs. 0.3° ± 0.5°, p < 0.001).

Conclusions

Bladder and small bowel doses were not significantly different when comparing VMAT plans developed for the prone and supine orientations. The supine orientation demonstrated improved setup reproducibility.

Local Excision of Rectal Cancer

Local excision (LE) of early-stage rectal cancer avoids the morbidity associated with radical surgery but has historically been associated with inferior oncologic outcomes. Newer techniques, including transanal endoscopic microsurgery (TEM) and transanal minimally invasive surgery (TAMIS), have been developed to improve the quality of LE and extend the benefits of LE to tumors in the more proximal rectum. This article provides an overview of conventional LE, TEM, and TAMIS techniques, including indications for their use and pertinent literature on their associated outcomes for rectal cancer.

Impact of Duration of Neoadjuvant Radiation on Rectal Cancer Survival: A Real World Multi-center Retrospective Cohort Study

BACKGROUND

The utility of neoadjuvant radiotherapy (nRT) for the treatment of stage II and III rectal cancer is well-established. However, the optimal duration of nRT in this setting remains controversial. Using a population-based cohort of patients with stage II and III rectal cancer (RC) treated with curative intent, our aims were to (1) examine the patterns of nRT use and (2) explore the relationship between different nRT schedules and survival in the real-world setting.

METHODS

This is a multi-center retrospective cohort study based on population-based data from 5 regional comprehensive cancer centers in British Columbia, Canada. We analyzed patients diagnosed with clinical stage II or III RC from 2006 to 2010 and treated with either short-course (SC) or long-course (LC) nRT prior to curative intent surgery. Logistic regression models were constructed to determine the factors associated with the course of nRT delivered to patients. Kaplan-Meier methods and Cox regression that accounted for known prognostic factors were used to evaluate the relationship between nRT schedule and overall (OS), disease-free (DFS), local recurrence-free (LRFS), and distant recurrence-free survival (DRFS).

RESULTS

We identified 427 patients: the median age was 65 years (range, 31 to 94 years), 67% were men, 87% had T3 or T4 tumors, and 74% had N1 or N2 disease. Among them, 241 (56%) received SC and 186 (44%) received LC. Adjusting for confounders, patients with N1 or N2 disease were more likely to undergo LC (odds ratio [OR], 5.08; 95% confidence interval [CI], 2.51-11.22; P < .0001 and OR, 8.35; 95% CI, 3.35-22.39; P < .0001, respectively), whereas older age patients were less likely to receive LC (OR, 0.95; 95% CI, 0.94-0.98; P < .0001). In Kaplan-Meier analysis, there were no significant differences observed in OS, DFS, LRFS, and DRFS between SC and LC. Likewise, multivariate analyses demonstrated that OS (hazard ratio [HR], 0.91; 95% CI, 0.61-1.37; P = .66), DFS (HR, 1.06; 95% CI, 0.68-1.64; P = .80), LRFS (HR, 0.79; 95% CI, 0.39-1.57; P = .50) and DRFS (HR, 0.99; 95% CI, 0.60-1.61; P = .95) were similar regardless of nRT schedules. Additional baseline clinical and tumor characteristics did not influence outcomes (all P > .05).

CONCLUSION

Appropriate preoperative selection of SC versus LC nRT for locally advanced RC based on patient and tumor characteristics was not associated with differences in survival outcomes in the real-world setting.