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). Ann Surg. 2017;265:882-888. [PMID: 27631775 DOI: 10.1097/sla.0000000000001987]

Intensity-modulated radiation therapy can reduce acute toxicities in long-course neoadjuvant radiation therapy combined with S-1 for locally advanced rectal cancer

BACKGROUND

The purpose of this study was to compare outcomes and adverse events between three-dimensional conformal radiation therapy (3D-CRT) and intensity-modulated radiation therapy (IMRT) in patients undergoing long-course neoadjuvant radiation therapy (NA-RT) for locally advanced rectal adenocarcinoma (LARC).

METHODS

We retrospectively analyzed a total of 47 consecutive patients who received NA-RT for LARC between January 2011 and September 2022. Seven and 40 patients were diagnosed with clinical stages II and III, respectively. The prescribed dose per fraction was 1.8 Gy for total doses of 45 or 50.4 Gy. Seventeen and 30 patients received 3D-CRT and IMRT, respectively. NA-RT was delivered with concurrent chemotherapy of oral administration of S-1.

RESULTS

Planned NA-RT was completed without any treatment interruption in 43 of the 47 patients. Two patients experienced treatment interruption, and two patients discontinued due to grade ≥ 3 toxicities. No significant differences were observed between patients receiving 3D-CRT and IMRT in local control, progression-free survival, and overall survival (P = 0.488, 0.259, and 0.636, respectively). Patients receiving IMRT showed significantly fewer non-hematological grade ≥ 2 acute toxicities than those receiving 3D-CRT (33.3% vs. 70.6%, P = 0.018). In addition, patients who received IMRT tended to have less intestinal toxicity of grade ≥ 2 than those who received 3D-CRT (P = 0.057).

CONCLUSION

IMRT significantly reduced grade ≥ 2 acute toxicities without compromising oncologic outcomes compared to 3D-CRT. Therefore, IMRT may be considered as a current standard treatment in the total neoadjuvant therapy era.

The Prevalence of 5-Fluorouracil and Capecitabine Cardiotoxicity: A Systematic Review and Meta-Analysis

Background

The incidence of cardiotoxicity events in patients who use 5-fluorouracil (5-FU) and capecitabine monotherapy remains unclear since previous studies reported the prevalence in patients who used combination regimens. We aimed to systematically review and meta-analyze the incidence of cardiotoxicity in fluorouracil and capecitabine monotherapy users.

Methods

The study protocol was registered with PROSPERO (CRD42023441627). Systematic searches were conducted in five databases (CINAHL, OpenGrey, PubMed, ScienceDirect, and Scopus). The Cochrane Risk-of-Bias tool and the Risk Of Bias In Non-randomized Studies were used to evaluate the risk of bias. Pooled prevalence and 95% confidence interval (CI) were calculated using the DerSimonian-Laird random effect models. The funnel plot was used to assess the publication bias.

Results

Eighty studies were included. There were 24 randomized controlled trials (RCTs) with low to high risk of bias and 56 non-RCTs with critical risk of bias. The pooled prevalence of cardiotoxicity from 5-FU was 3.5% (95% CI: 2.7 - 4.2; P < 0.001; I2 = 73.86%). The pooled prevalence of cardiotoxicity in capecitabine users was 2.8% (95% CI: 1.6 - 4.0; P < 0.001; I2 = 72.62%).

Conclusions

The prevalence of cardiotoxicity from 5-FU and capecitabine was classified as common. Cardiotoxicity may have not been associated with the cumulative dose of 5-FU or capecitabine.

Localized Rectal Cancer: Indian Consensus and Guidelines

The rising incidence of colorectal cancer (CRC) in India, particularly the prevalence of rectal cancer over colon cancer (0.7:1), has been a growing concern in recent decades; especially notable is the trend of increasing cases among young CRC patients. Given the diverse treatment approaches for rectal cancer globally and the varying economic capacities of patients in low to middle-income countries (LMICs) like India, it is essential to establish consensus guidelines that are specifically tailored to meet the needs of these patients. To achieve this, a panel comprising 30 eminent rectal cancer experts convened to conduct a comprehensive and impartial evaluation of existing practices and recent advancements in the field. Through meticulous scrutiny of published literature and a consensus-building process that involved voting on pertinent questions, the panel formulated management strategies. These recommendations are the result of a rigorous, evidence-based process and encapsulate the collective wisdom and judgment of leading authorities in the field.

Executive Summary of the American Radium Society on Appropriate Use Criteria for Nonoperative Management of Rectal Adenocarcinoma: Systematic Review and Guidelines

For patients with rectal cancer, the standard approach of chemotherapy, radiation therapy, and surgery (trimodality therapy) is associated with significant long-term toxicity and/or colostomy for most patients. Patient options focused on quality of life (QOL) have dramatically improved, but there remains limited guidance regarding comparative effectiveness. This systematic review and associated guidelines evaluate how various treatment strategies compare to each other in terms of oncologic outcomes and QOL. Cochrane and Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) methodology were used to search for prospective and retrospective trials and meta-analyses of adequate quality within the Ovid Medline database between January 1, 2012, and June 15, 2023. These studies informed the expert panel, which rated the appropriateness of various treatments in 6 clinical scenarios through a well-established consensus methodology (modified Delphi). The search process yielded 197 articles that advised voting. Increasing data have shown that nonoperative management (NOM) and primary surgery result in QOL benefits noted over trimodality therapy without detriment to oncologic outcomes. For patients with rectal cancer for whom total mesorectal excision would result in permanent colostomy or inadequate bowel continence, NOM was strongly recommended as usually appropriate. Restaging with tumor response assessment approximately 8 to 12 weeks after completion of radiation therapy/chemoradiation therapy was deemed a necessary component of NOM. The panel recommended active surveillance in the setting of a near-complete or complete response. In the setting of NOM, 54 to 56 Gy in 27 to 31 fractions concurrent with chemotherapy and followed by consolidation chemotherapy was recommended. The panel strongly recommends primary surgery as usually appropriate for a T3N0 high rectal tumor for which low anterior resection and adequate bowel function is possible, with adjuvant chemotherapy considered if N+. Recent data support NOM and primary surgery as important options that should be offered to eligible patients. Considering the complexity of multidisciplinary management, patients should be discussed in a multidisciplinary setting, and therapy should be tailored to individual patient goals/values.

Efficacy and safety of combining short-course neoadjuvant chemoradiotherapy with envafolimab in locally advanced rectal cancer patients with microsatellite stability: A phase II PRECAM experimental study

BACKGROUND

Conventional neoadjuvant chemoradiotherapy (nCRT) yields a pathologic complete response (pCR) rate of 15%-30% for locally advanced rectal cancer (LARC). This study ventures to shift this paradigm by incorporating short-course nCRT with immunotherapy, specifically Envafolimab, to achieve improved treatment efficacy and possibly redefine the standard of care for LARC.

MATERIALS AND METHODS

The PRECAM study is a prospective, single-arm, phase 2 clinical trial for LARC in patients with microsatellite stable (MSS) tumors. Participants received short-course radiotherapy (25Gy/5f), followed by two cycles of CAPEOX chemotherapy and six weekly doses of Envafolimab, a PD-L1 antibody, before total mesorectal excision surgery. The primary endpoint was the pCR rate.

RESULTS

From April to December 2022, 34 patients were enrolled, of whom 32 completed the study, each diagnosed with an MSS rectal adenocarcinoma. All patients underwent preoperative CRT combined with Envafolimab. Remarkably, a pCR rate of 62.5% (20/32) was attained, and a significant pathologic response rate of 75% (24/32) was achieved. Additionally, 21 of 32 participants achieved a neoadjuvant rectal (NAR) score below 8, suggesting an effective treatment response. Common adverse events included tenesmus (78.1%), diarrhea (62.5%), and leukocyte decrease (40.6%). Two Grade 3 adverse events were noted, one related to liver function abnormality and the other to a decrease in platelet count. Surgical procedures were performed in all cases, with minor complications, including ileus, infections, and anastomotic leakage. As of this report, there have been no reported cases of recurrence or death during the follow-up period, ranging from 12 to 20 months.

CONCLUSION

In LARC patients exhibiting MSS tumors, combining short-course nCRT with Envafolimab demonstrated favorable efficacy, leading to a significant pCR rate. Minor adverse effects and surgical complications were observed. These preliminary but promising results underscore the potential of this approach and call for further exploration and validation through a randomized controlled trial.

Radiotherapy for Rectal Cancer: How Much is Enough?

Though resection has been the mainstay of treatment for nonmetastatic rectal cancer over the past century, radiation has become an increasingly integral component of care for locally advanced disease. Today, two predominant radiotherapy approaches-hyperfractionated chemoradiotherapy and "short-course" radiation-are widely utilized to reduce local recurrence and, in some cases, cure disease. Both have been incorporated into total neoadjuvant therapy (TNT) regimens and achieved excellent local control and superior complete response rates compared to chemoradiation alone. Additionally, initial results of "watch and wait" protocols utilizing either radiation modality have been promising. Yet, differences do exist; though short course is cheaper and more convenient for patients, recently published data may show superior complete response and local recurrence rates with chemoradiation. Ultimately, direct comparisons of short-course radiotherapy against chemoradiation within the TNT framework are needed to identify optimal radiation regimens in the treatment of locally advanced rectal cancer.

Treatment of Locally Advanced Rectal Cancer in the Era of Total Neoadjuvant Therapy: A Systematic Review and Network Meta-Analysis

Importance

Treatment of locally advanced rectal cancer (LARC) involves neoadjuvant chemoradiotherapy plus total mesorectal excision and adjuvant chemotherapy. However, total neoadjuvant therapy (TNT) protocols (ie, preoperative chemotherapy in addition to radiotherapy) may allow better adherence and early treatment of distant micrometastases and may increase pathological complete response (pCR) rates.

Objective

To assess the efficacy and tolerability of TNT protocols for LARC.

Data Sources

MEDLINE, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), and Web of Science Core Collection electronic databases and ClinicalTrials.gov for unpublished studies were searched from inception to March 2, 2024.

Study Selection

Randomized clinical trials including adults with LARC who underwent rectal resection as a final treatment were included. Studies including nonoperative treatment (watch-and-wait strategy), treatments other than rectal resection, immunotherapy, or antiangiogenic agents were excluded. Among the initially identified studies, 2.9% met the selection criteria.

Data Extraction and Synthesis

Two authors independently screened the records and extracted data. Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA)-compliant pairwise and network meta-analyses with a random-effects model were performed in a frequentist framework, and the certainty of evidence was assessed according to the confidence in network meta-analysis approach.

Main Outcomes and Measures

The primary outcome was pCR, defined as the absence of residual tumor at pathological assessment after surgery. Secondary outcomes included tolerability, toxic effects, perioperative outcomes, and long-term survival.

Results

Of 925 records identified, 27 randomized clinical trials, including 13 413 adults aged 18 years or older (median age, 60.0 years [range, 42.0-63.5 years]; 67.2% male) contributed to the primary network meta-analysis. With regard to pCR, long-course chemoradiotherapy (L-CRT) plus consolidation chemotherapy (relative risk [RR], 1.96; 95% CI, 1.25-3.06), short-course radiotherapy (S-RT) plus consolidation chemotherapy (RR, 1.76; 95% CI, 1.34-2.30), and induction chemotherapy plus L-CRT (RR, 1.57; 95% CI, 1.09-2.25) outperformed standard L-CRT with single-agent fluoropyrimidine-based chemotherapy. Considering 3-year disease-free survival, S-RT plus consolidation chemotherapy (RR, 1.08; 95% CI, 1.01-1.14) and induction chemotherapy plus L-CRT (RR, 1.12; 95% CI, 1.01-1.24) outperformed L-CRT, in spite of an increased 5-year locoregional recurrence rate of S-RT plus consolidation chemotherapy (RR, 1.65; 95% CI, 1.03-2.63).

Conclusions and Relevance

In this systematic review and network meta-analysis, 3 TNT protocols were identified to outperform the current standard of care in terms of pCR rates, with good tolerability and optimal postoperative outcomes, suggesting they should be recognized as first-line treatments.

Efficient combination of radiotherapy and CAR-T - A systematic review

Chimeric antigen receptor T (CAR-T) cell therapy, a groundbreaking immunotherapy. However, it faces formidable challenges in treating solid tumors, grappling with issues like poor trafficking, limited penetration, and insufficient persistence within the tumor microenvironment (TME). CAR-T cells are engineered to express receptors that target specific cancer antigens, enhancing their ability to recognize and eliminate cancer cells. This review paper explores the intricate interplay between CAR-T therapy and radiotherapy (RT), investigating their synergistic potential. Radiotherapy, a standard cancer treatment, involves using high doses of radiation to target and damage cancer cells, disrupting their ability to grow and divide. We highlight that RT modulates the TME, augments antigen presentation, and promotes immune cell infiltration, bolstering CAR-T cell-mediated tumor eradication. Molecular insights shed light on RT-induced alterations in tumor stroma, T cell recruitment promotion, and induction of immunogenic cell death. Noteworthy, strategies, such as combining hypofractionated radiotherapy with myeloid-derived suppressor cell blockade, underscore innovative approaches to enhance CAR-T cell therapy in solid tumors. Bridging indications for RT and CAR-T cells in hematological malignancies are discussed, emphasizing scenarios where RT strategically enhances CAR-T cell efficacy. The paper critically evaluates the RT as a bridge compared to traditional chemotherapy, highlighting timing and dosage considerations crucial for optimizing CAR-T therapy outcomes. In summary, the paper provides valuable insights into the intricate molecular mechanisms activated by RT and innovative strategies to improve CAR-T cell therapy, fostering a deeper understanding of their combined potential in cancer treatment.

What affects the selection of diverting ileostomy in rectal cancer surgery: a single-center retrospective study

BACKGROUND

The selection of diverting ileostomy (DI) is controversial. This study aimed to explore the factors affecting the selection of diverting ileostomy (DI) following laparoscopic low anterior resection for rectal cancer.

METHODS

This retrospective, case-control study included patients who underwent laparoscopic-assisted sphincter-saving surgery for mid-low rectal cancer from January 2019 to June 2021. Univariate and multivariate analyses were performed on the patient's clinicopathological characteristics and pelvic dimensions measured by abdominopelvic electron beam computed tomography.

RESULTS

A total of 382 patients were included in the analysis, of which 182 patients (47.6%) did not undergo DI, and 200 patients (52.4%) underwent DI. The univariate analysis suggested that male sex (p = 0.003), preoperative radiotherapy (p < 0.001), patients with an anastomosis below the levator ani plane (p < 0.001), the intertuberous distance (p < 0.001), the sacrococcygeal distance (p = 0.025), the mid pelvis anteroposterior diameter (p = 0.009), and the interspinous distance (p < 0.001) were associated with performing DI. Multivariate analysis confirmed that preoperative radiotherapy (p = 0.037, odds ratio [OR] = 2.98, 95% confidence interval [CI] = 1.07-8.30), anastomosis below the levator ani plane (p < 0.001, OR = 7.09, 95% CI = 4.13-12.18), and the interspinous distance (p = 0.047, OR = 0.97, 95% CI = 0.93-1.00) were independently associated with performing DI.

CONCLUSION

Pelvic parameters also influence the choice of DI. According to this single-center experience, patients with a shorter interspinous distance, particularly narrow pelvic with an interspinous distance of < 94.8 mm, preoperative radiotherapy, and anastomosis below the levator ani plane, prefer to have a DI and should be adequately prepared by the physician.

Quality of Surgical Outcome Reporting in Randomised Clinical Trials of Multimodal Rectal Cancer Treatment: A Systematic Review

INTRODUCTION

Randomised controlled trials (RCTs) continue to provide the best evidence for treatment options, but the quality of reporting in RCTs and the completeness rate of reporting of surgical outcomes and complication data vary widely. The aim of this study was to measure the quality of reporting of the surgical outcome and complication data in RCTs of rectal cancer treatment and whether this quality has changed over time.

METHODS

Eligible articles with the keywords ("rectal cancer" OR "rectal carcinoma") AND ("radiation" OR "radiotherapy") that were RCTs and published in the English, German, Polish, or Italian language were identified by reviewing all abstracts published from 1982 through 2022. Two authors independently screened and analysed all studies. The quality of the surgical outcome and complication data was assessed based on fourteen criteria, and the quality of RCTs was evaluated based on a modified Jadad scale. The primary outcome was the quality of reporting in RCTs and the completeness rate of reporting of surgical results and complication data.

RESULTS

A total of 340 articles reporting multimodal therapy outcomes for 143,576 rectal cancer patients were analysed. A total of 7 articles (2%) met all 14 reporting criteria, 13 met 13 criteria, 27 met from 11 to 12 criteria, 36 met from 9 to 10 criteria, 76 met from 7 to 8 criteria, and most articles met fewer than 7 criteria (mean 5.5 criteria). Commonly underreported criteria included complication severity (15% of articles), macroscopic integrity of mesorectal excision (17% of articles), length of stay (18% of articles), number of lymph nodes (21% of articles), distance between the tumour and circumferential resection margin (CRM) (26% of articles), surgical radicality according to the site of the primary tumour (R0 vs. R1 + R2) (29% of articles), and CRM status (38% of articles).

CONCLUSION

Inconsistent surgical outcome and complication data reporting in multimodal rectal cancer treatment RCTs is standard. Standardised reporting of clinical and oncological outcomes should be established to facilitate comparing studies and results of related research topics.

Omentoplasty in Patients Undergoing Abdominoperineal Resection After Long-Course Chemoradiation for Locally Advanced and Locally Recurrent Rectal Cancer: A Comparative Single-Institution Cohort Study

BACKGROUND

Omentoplasty is a commonly performed procedure after abdominoperineal resection for rectal cancer, but its effectiveness to reduce pelviperineal complications is not firmly established.

OBJECTIVE

This study aimed to assess the impact of omentoplasty on postoperative outcomes after long-course (chemo) radiotherapy and abdominoperineal resection in patients with locally advanced and locally recurrent rectal cancer.

DESIGN

Retrospective cohort study.

SETTINGS

Single center.

PATIENTS

All patients with locally advanced and locally recurrent rectal cancer undergoing abdominoperineal resection after neoadjuvant (chemo)radiation in a tertiary referral center between 2008 and 2020 were retrospectively reviewed.

MAIN OUTCOME MEASURES

Multivariable logistic and linear regression analyses were performed to analyze the association between omentoplasty and pelviperineal complications, duration of nasogastric tube drainage, and length of hospital stay.

RESULTS

A total of 305 patients were analyzed, of whom 245 underwent omentoplasty (80%). Pelviperineal complications occurred in 151 patients (50%) overall, in 125 patients (51%) with omentoplasty, and in 26 patients (43%) without omentoplasty. Independent predictors of pelviperineal complications in multivariable analyses were smoking (OR 2.68; 95% CI, 1.46-4.94) and high BMI (OR 1.68; 95% CI, 1.00-2.83), but not omentoplasty (OR 1.36; 95% CI, 0.77-2.40). The mean duration of nasogastric tube drainage was longer after omentoplasty (6 vs 4 d) with a significant association in multivariable analysis (β coefficient 1.97; 95% CI, 0.35-3.59). Patients undergoing omentoplasty had a significantly longer hospital stay (14 vs 10 d), and omentoplasty remained associated with a prolonged hospital stay after adjusting for confounding (β coefficient 3.05; 95% CI, 0.05-5.74).

LIMITATIONS

Retrospective design.

CONCLUSION

Omentoplasty was not associated with a reduced risk of the occurrence of short-term pelviperineal complications after abdominoperineal resection in patients undergoing long-course (chemo)radiotherapy. Furthermore, in patients undergoing omentoplasty, prolonged duration of nasogastric tube drainage and hospital stay was observed. See Video Abstract at http://links.lww.com/DCR/C124 .

OMENTOPLASTIA EN PACIENTES SOMETIDOS A RESECCIN ABDOMINOPERINEAL DESPUS DE QUIMIORRADIOTERAPIA DE CURSO LARGO PARA EL CNCER DE RECTO LOCALMENTE AVANZADO Y LOCALMENTE RECURRENTE ESTUDIO DE COHORTE COMPARATIVO DE UNA SOLA INSTITUCIN

ANTECEDENTES:La omentoplastía es un procedimiento que se realiza comúnmente después de la resección abdominoperineal por cáncer de recto, pero su efectividad para reducir las complicaciones pelvicoperineales no está firmemente establecida.OBJETIVO:Evaluar el impacto de la omentoplastía en las complicaciones pelvicoperineales a corto plazo y los resultados postoperatorios después quimioradioterapia de curso largo y resección abdominoperineal en pacientes con cáncer de recto localmente avanzado y localmente recurrente.DISEÑO:Estudio de cohorte retrospectivo.ESCENARIO:Centro único.PACIENTES:Se revisaron retrospectivamente todos los pacientes con cáncer de recto localmente avanzado y localmente recurrente sometidos a resección abdominoperineal después de quimioradiación neoadyuvante en un centro de referencia de tercer nivel entre 2008 y 2020.PRINCIPALES MEDIDAS DE RESULTADO:Se realizaron análisis de regresión lineal y logística multivariable para examinar la asociación entre la omentoplastía y las complicaciones pelvicoperineales (p. ej., problemas de heridas perineales y abscesos pélvicos), la duración del drenaje por sonda nasogástrica y la duración de la estancia hospitalaria.RESULTADOS:Se analizaron un total de 305 pacientes de los cuales 245 fueron sometidos a omentoplastía (80%). Las complicaciones pelvicoperineales ocurrieron en 151 pacientes (50%) en general, y en 125 (51%) y 26 (43%) de los pacientes con o sin omentoplastía, respectivamente. Los predictores independientes de complicaciones pelvicoperineales en análisis multivariable fueron el tabaquismo (OR 2.68, IC del 95% 1.46 a 4.94) y un IMC alto (OR 1.68, IC del 95% 1.00 a 2.83), pero no la omentoplastía (OR 1.36, IC del 95% 0.77 a 2.40) . La duración media del drenaje por sonda nasogástrica fue mayor después de la omentoplastía (6 frente a 4 días) con una asociación significativa en el análisis multivariable (coeficiente β 1.97, IC del 95%: 0.35-3.59). Los pacientes que se sometieron a una omentoplastía tuvieron una estancia hospitalaria significativamente más larga (14 frente a 10 días), y la omentoplastía permaneció asociada con una estancia hospitalaria prolongada después de ajustar por factores de confusión (coeficiente β 3.05, IC del 95%: 0.05-5.74).LIMITACIONES:Diseño retrospectivo.CONCLUSIÓN:La omentoplastía no se asoció con un riesgo reducido de aparición de complicaciones pelvicoperineales a corto plazo después de la resección abdominoperineal en pacientes sometidos a quimioradioterapia de larga duración. Adicionalmente, en los pacientes sometidos a omentoplastía se observó una duración prolongada del drenaje por sonda nasogástrica y la estancia hospitalaria. Consulte Video Resumen en http://links.lww.com/DCR/C124 . (Traducción-Dr. Jorge Silva Velazco ).

Cancer nanomedicine in preoperative therapeutics: Nanotechnology-enabled neoadjuvant chemotherapy, radiotherapy, immunotherapy, and phototherapy

Surgical resection remains a mainstay in the treatment of malignant solid tumors. However, the use of neoadjuvant treatments, including chemotherapy, radiotherapy, phototherapy, and immunotherapy, either alone or in combination, as a preoperative intervention regimen, have attracted increasing attention in the last decade. Early randomized, controlled trials in some tumor settings have not shown a significant difference between the survival rates in long-term neoadjuvant therapy and adjuvant therapy. However, this has not hampered the increasing use of neoadjuvant treatments in clinical practice, due to its evident downstaging of primary tumors to delineate the surgical margin, tailoring systemic therapy response as a clinical tool to optimize subsequent therapeutic regimens, and decreasing the need for surgery, with its potential for increased morbidity. The recent expansion of nanotechnology-based nanomedicine and related medical technologies provides a new approach to address the current challenges of neoadjuvant therapy for preoperative therapeutics. This review not only summarizes how nanomedicine plays an important role in a range of neoadjuvant therapeutic modalities, but also highlights the potential use of nanomedicine as neoadjuvant therapy in preclinical and clinic settings for tumor management.

Patient-reported Bowel Function and Bowel-related Quality of Life After Pelvic Radiation for Rectal Adenocarcinoma: The Impact of Radiation Fractionation and Surgical Resection

INTRODUCTION

Multimodality treatment for locally advanced rectal cancer (LARC) can include long-course radiotherapy (LCRT) or short course radiotherapy (SCRT). Nonoperative management is increasingly pursued for those achieving a complete clinical response. Data regarding long-term function and quality-of-life (QOL) are limited.

METHODS

Patients with LARC treated with radiotherapy from 2016 to 2020 completed the Functional Assessment of Cancer Therapy- General (FACT-G7), the Low Anterior Resection Syndrome Score (LARS) and the Fecal Incontinence QOL Scale (FIQOL). Univariate and multivariable linear regression analyses identified associations between clinical variables including radiation fractionation and the use of surgery versus non-operative management.

RESULTS

Of 204 patients surveyed, 124 (60.8%) responded. Median (interquartile range) time from radiation to survey completion was 30.1 (18.3-43) months. Seventy-nine (63.7%) respondents received LCRT, and 45 (36.3%) received SCRT; 101 (81.5%) respondents underwent surgery, and 23 (18.5%) pursued nonoperative management. There were no differences in LARS, FIQoL or FACT-G7 between patients receiving LCRT versus SCRT. On multivariable analysis, only nonoperative management was associated with lower LARS score signifying less bowel dysfunction. Nonoperative management and female sex were associated with a higher FIQoL score signifying less disruption and distress from fecal incontinence issues. Finally, lower BMI at the time of radiation, female sex, and higher FIQoL score were associated with higher FACT-G7 scores signifying better overall QOL.

CONCLUSIONS

These results suggest long-term patient-reported bowel function and QOL may be similar for individuals receiving SCRT and LCRT for the treatment of LARC, but nonoperative management may lead to improved bowel function and QOL.

New Opportunities for Minimizing Toxicity in Rectal Cancer Management

Advances in multimodal management of locally advanced rectal cancer (LARC), consisting of preoperative chemotherapy and/or radiotherapy followed by surgery with or without adjuvant chemotherapy, have improved local disease control and patient survival but are associated with significant risk for acute and long-term morbidity. Recently published trials, evaluating treatment dose intensification via the addition of preoperative induction or consolidation chemotherapy (total neoadjuvant therapy [TNT]), have demonstrated improved tumor response rates while maintaining acceptable toxicity. In addition, TNT has led to an increased number of patients achieving a clinical complete response and thus eligible to pursue a nonoperative, organ-preserving, watch and wait approach, thereby avoiding toxicities associated with surgery, such as bowel dysfunction and stoma-related complications. Ongoing trials using immune checkpoint inhibitors in patients with mismatch repair-deficient tumors suggest that this subgroup of patients with LARC could potentially be treated with immunotherapy alone, sparing them the toxicity associated with preoperative treatment and surgery. However, the majority of rectal cancers are mismatch repair-proficient and less responsive to immune checkpoint inhibitors and require multimodal management. The synergy noted in preclinical studies between immunotherapy and radiotherapy on immunogenic tumor cell death has led to the design of ongoing clinical trials that explore the benefit of combining radiotherapy, chemotherapy, and immunotherapy (mainly of immune checkpoint inhibitors) and aim to increase the number of patients eligible for organ preservation.

Radioimmunotherapy in colorectal cancer treatment: present and future

Colorectal cancer (CRC) is a deadly form of cancer worldwide. Patients with locally advanced rectal cancer and metastatic CRC have a poor long-term prognosis, and rational and effective treatment remains a major challenge. Common treatments include multi-modal combinations of surgery, radiotherapy, and chemotherapy; however, recurrence and metastasis rates remain high. The combination of radiotherapy and immunotherapy (radioimmunotherapy [RIT]) may offer new solutions to this problem, but its prospects remain uncertain. This review aimed to summarize the current applications of radiotherapy and immunotherapy, elaborate on the underlying mechanisms, and systematically review the preliminary results of RIT-related clinical trials for CRC. Studies have identified several key predictors of RIT efficacy. Summarily, rational RIT regimens can improve the outcomes of some patients with CRC, but current study designs have limitations. Further studies on RIT should focus on including larger sample sizes and optimizing the combination therapy regimen based on underlying influencing factors.

A systematic review and network meta-analysis of randomised controlled trials comparing neoadjuvant treatment strategies for stage II and III rectal cancer

AIM

Multiple neoadjuvant therapy strategies have been used and compared for rectal cancer and there has been no true consensus as to the optimal neoadjuvant therapy regimen. The aim is to identify and compare the neoadjuvant therapies available for stage II and III rectal cancer.

DESIGN

A systematic literature review was performed, from inception to August 2022, of the following databases: MEDLINE, EMBASE, Science Citation Index Expanded, Cochrane Library. Only randomized controlled trials comparing neoadjuvant therapies for stage II and III rectal cancer were considered. Stata was used to draw network plots, and a Bayesian network meta-analysis was conducted through models utilizing the Markov Chain Monte Carlo method in WinBUGS.

RESULTS

A total of 58 articles were included based on 41 randomised controlled trials, reporting on 12,404 participants that underwent 15 neoadjuvant treatment regimens. No significant difference was identified between treatments for major or total postoperative complications, anastomotic leak rates, or sphincter-saving surgery. Straight to surgery (STS) ranked as best treatment for preoperative toxicity but ranked worst treatment for positive resection margins and complete response. STS had significantly increased positive resection margins compared to long-course chemoradiotherapy with short-wait (LCCRT-SW) or long-wait (LCCRT-LW) to surgery, or short-course radiotherapy with short-wait (SCRT-SW) or immediate surgery (SCRT-IS). LCCRT-SW or LCCRT-LW resulted in significantly increased complete response rates compared to STS. LCCRT-LW significantly improved 2-year overall survival compared to STS, SCRT-IS, SCRT-SW. Total neoadjuvant therapy regimes with short-course radiotherapy followed by consolidation chemotherapy (SCRT-CT-SW), induction chemotherapy followed by long-course chemoradiotherapy (CT-LCCRT-S), long-course chemoradiotherapy followed by consolidation chemotherapy (LCCRT-CT-S), significantly improved positive resection margins, complete response, and disease-free survival compared to STS. Chemotherapy with monoclonal antibodies followed by long-course chemoradiotherapy (CT+MAB-LCCRT+MAB-S) significantly improved complete response and positive resection margins compared to STS, and 2-year disease-free survival compared to STS, SCRT-IS, SCRT-SW, SCRT-CT-SW, LCCRT-SW, LCCRT-LW. CT+MAB-LCCRT+MAB-S ranked as best treatment for disease-free survival and overall survival.

CONCLUSIONS

Conventional neoadjuvant therapies with short-course radiation or long-course chemoradiotherapy have oncological benefits compared to no neoadjuvant therapy without increasing perioperative complication rates. Prolonged wait to surgery may improve oncological outcomes. Total neoadjuvant therapies provide additional benefits in terms of complete response, positive resection margins, and disease-free survival. Monoclonal antibody therapy may further improve oncological outcomes but currently is only applicable to a small subgroup of patients and requires further validation.

Acute toxicities of patients with locally advanced rectal cancer treated with intensified chemoradiotherapy within the CAO/ARO/AIO-12 trial: comparing conventional versus VMAT planning at a single center

In locally advanced rectal cancer (LARC) neoadjuvant chemoradiotherapy is regarded as standard treatment. We assessed acute toxicities in patients receiving conventional 3D-conformal radiotherapy (3D-RT) and correlated them with dosimetric parameters after re-planning with volumetric modulated arc therapy (VMAT). Patients were randomized within the multicenter CAO/ARO/AIO-12 trial and received 50.4 Gy in 28 fractions and simultaneous chemotherapy with fluorouracil and oxaliplatin. Organs at risk (OAR) were contoured in a standardized approach. Acute toxicities and dose volume histogram parameters of 3D-RT plans were compared to retrospectively calculated VMAT plans. From 08/2015 to 01/2018, 35 patients with LARC were treated at one study center. Thirty-four patients were analyzed of whom 1 (3%) was UICC stage II and 33 (97%) patients were UICC stage III. Grade 3 acute toxicities occurred in 5 patients (15%). Patients with acute grade 1 cystitis (n = 9) had significantly higher D_mean values for bladder (29.4 Gy vs. 25.2 Gy, p < 0.01) compared to patients without bladder toxicities. Acute diarrhea was associated with small bowel volume (grade 2: 870.1 ccm vs. grade 0-1: 647.3 ccm; p < 0.01) and with the irradiated volumes V5 to V50. Using VMAT planning, we could reduce mean doses and irradiated volumes for all OAR: D_mean bladder (21.9 Gy vs. 26.3 Gy, p < 0.01), small bowel volumes V5-V45 (p < 0.01), D_mean anal sphincter (34.6 Gy vs. 35.6 Gy, p < 0.01) and D_mean femoral heads (right 11.4 Gy vs. 25.9 Gy, left 12.5 Gy vs. 26.6 Gy, p < 0.01). Acute small bowel and bladder toxicities were dose and volume dependent. Dose and volume sparing for all OAR could be achieved through VMAT planning and might result in less acute toxicities.

Predictors of Definitive Treatment Interruptions of Long-Course Neoadjuvant Chemoradiotherapy in Locally Advanced Rectal Cancer

Introduction To identify predictors of definitive treatment interruptions (DTI) of the neoadjuvant long-course radiotherapy (LCRT) in locally advanced rectal cancer (LARC), and to determine their impact on clinical outcomes. Methods Patients with stage II-III LARC treated between 2009-2018 were retrospectively analyzed (n=101, median FU 49.5 months). Logistic regression models evaluated the impact of relevant clinical variables on grade 3 or greater (G3+) acute toxicity, definitive treatment interruption (DTI), pCR, and definitive ostomy (dOST) rates. The secondary outcomes were LRC, MFS, PFS, CSS, and OS. Results The incidences of grade 3 and 4 toxicities were 25.3%, and 1.1%, respectively. The most common G3+ toxicities were peri-anal dermatitis (14.7%) and diarrhea (7.4%), which were more frequent in females (p=0.040) and tumors close to the anal verge (p=0.019). In this study, 11 patients (10.9%) developed DTI, which was associated with these G3+ events (p<0.001). Resection occurred after 7.1 weeks (median, IQR:6.1-8.9). Downstaging occurred in 57.4% (17.8% pCR), 88% achieved negative margins and the dOST rate was 56.4%. The five-year LRC, MFS, PFS, CSS and OS were: 94.4%, 78.9%, 74.7%, 85.2% and 81.6%, respectively. DTI events did not impact any outcome. The factors associated with loco-regional failure were close/positive margins (p<0.001) and stage ypIII (p=0.002). Conclusions: Tumors close to the anal verge and female sex were associated with increased G3+ toxicity, which was predictive of DTI. The resultant partial/complete omission of the planned boost, however, dose did not increase the chance of LR. Further studies to clarify the benefit and optimal timing to deliver the boost are warranted, especially for positive margins.

Zebrafish Avatars of rectal cancer patients validate the radiosensitive effect of metformin

Neoadjuvant chemoradiation (nCRT) followed by surgery represents the standard of care in patients with locally advanced rectal cancer. Increasing radiotherapy (RT) doses and chemotherapy cycles with 5FU have been associated with increased rates of complete response, however these strategies imply significant toxicity. In the last years, epidemiologic findings have demonstrated that metformin is associated with significantly higher rates of pathological complete response to nCRT. Also, pre-clinical studies using cell lines provide evidence for the radiosensitive effect of metformin. However, no studies have been performed using rectal cancer patient samples to test this radiosensitive effect of metformin and compared it to the standard 5FU. Here, we designed an experimental study to compare both radiosensitizers in the zebrafish xenograft model (zAvatar), using rectal cancer surgical specimens and diagnostic biopsies. Patient zAvatars confirmed that metformin has indeed a powerful in vivo radiosensitizer effect, similar to 5FU. Our work confirms that metformin constitutes a promising less toxic alternative to the standard 5FU, which could be game changing in elderly/frail patients to optimize tumor regression.

Incidence and risk factors for parastomal hernia with a permanent colostomy

AIM

This study aims to explore the incidence and risk factors for permanent colostomy complicated with a parastomal hernia (PSH) after rectal cancer resection.

METHODS

This was a retrospective study of gastrointestinal surgery performed from January 2013 to December 2017 in patients with colorectal cancer treated at the Affiliated Hospital of Qingdao University. The relevant clinical variables of the patient were analyzed. Kaplan-Meier, univariate, and Cox multivariate analyses were used to evaluate the influencing factors and morbidity of PSH.

RESULTS

Among the 211 patients, 65 developed PSH. The cumulative incidence reached 33.5% at 62 months. In the multivariate Cox survival analysis, the results showed that being a woman, aged ≥65 years, having a body mass index (BMI) ≥ 25 kg/m² , diabetes, and Clavien-Dindo Grade III and IV complications were risk factors for the occurrence of PSH.

CONCLUSION

In our study, the incidence of PSH increased annually and reached a maximum of 33.5% after 62 months. Among the patient-related factors, female sex, age ≥65 years, BMI ≥ 25 kg/m² , diabetes, and postoperative Clavien-Dindo Grade III and IV complications were significantly associated with the development of PSH. Therefore, intervention measures to prevent patients with this risk factor are advisable.

Efficacy and Safety of Preoperative Radiotherapy Versus Chemoradiotherapy in Advanced Rectal Cancer: A Meta-analysis of Randomized Controlled Trials

OBJECTIVE

This meta-analysis was conducted to evaluate the safety and efficacy of preoperative radiotherapy (RT) combined with surgery and preoperative chemoradiotherapy (CRT) combined with surgery for locally advanced rectal cancer.

METHODS

PubMed, EMBASE and Cochrane Library were searched to collect published randomized controlled trials of preoperative radiotherapy or preoperative CRT combined with surgery for the treatment of locally advanced rectal cancer. Studies were screened according to inclusion and exclusion criteria, and quality was evaluated; RevMan 5.3 software was used for meta-analysis.

RESULTS

In total, 7 related studies involving 3100 patients with locally advanced rectal cancer were evaluated. The pathological complete response rate, negative lymph node rate, R0 resection rate, and incidence of grade III/IV adverse reactions were lower in the RT group than in the CRT group. In the absence of postoperative chemotherapy, the 5-year local recurrence rate of RT was higher than that of CRT, but there was no significant difference between the groups among those who underwent postoperative chemotherapy. Moreover, there was no significant difference between the groups with regard to the 5-year survival rate, anal-preserving rate, or incidence of anastomotic leakage.

CONCLUSION

Preoperative CRT is better than preoperative RT for the treatment of advanced rectal cancer, though the adverse reaction rate is higher.

New Frontiers in Management of Early and Advanced Rectal Cancer

It is important to understand advances in treatment options for rectal cancer. We attempt to highlight advances in rectal cancer treatment in the form of a systematic review. Early-stage rectal cancer focuses on minimally invasive endoluminal surgery, with importance placed on patient selection as the driving factor for improved outcomes. To achieve a complete pathologic response, various neoadjuvant chemoradiation regimens have been employed. Short-course radiation therapy, total neoadjuvant chemotherapy, and others provide unique advantages with select patient populations best suited for each. With a clinical complete response, a "watch and wait" non-operative surveillance has been introduced with preliminary equivalency to radical resection. Various modalities for total mesorectal excision, such as robotic or transanal, have advantages and can be utilized in select patient populations. Tumors demonstrating solid organ or peritoneal spread, traditionally defined as unresectable lesions conveying a terminal diagnosis, have recently undergone advances in hepatic and pulmonary metastasectomy. Hepatic and pulmonary metastasectomy has demonstrated clear advantages in 5-year survival over standard chemotherapy. With the peritoneal spread of colorectal cancer, HIPEC with cytoreductive therapy has emerged as the preferred treatment. Understanding the various therapeutic interventions will pave the way for improved patient outcomes.

Uses of Personal Health Records for Communication Among Colorectal Cancer Survivors, Caregivers, and Providers: Interview and Observational Study in a Human-Computer Interaction Laboratory

BACKGROUND

Personal health records (PHRs) may be useful for patient self-management and participation in communication with their caregivers and health care providers. As each potential participant's role is different, their perception of the best uses of a PHR may vary.

OBJECTIVE

The perspectives of patients, caregivers, and providers were all evaluated concurrently in relation to a PHR developed for colorectal cancer (CRC) survivors.

METHODS

We explored group perceptions of a CRC PHR prototype. Scenario-based testing across eight use cases, with semistructured follow-up interviews, was videotaped in a human-computer interaction laboratory with patients, caregivers, and health care providers. Providers included oncologists, gastroenterologists, and primary care physicians. Discrete observations underwent grounded theory visual affinity analysis to identify emergent themes.

RESULTS

Observations fell into three major themes: the network (who should be granted access to the PHR by the patient), functions (helpful activities the PHR enabled), and implementation (how to adopt the PHR into workflow). Patients wanted physician access to their PHR, as well as family member access, especially when they lived at a distance. All groups noted the added value of linking the PHR to an electronic health record, self-tracking, self-management, and secure messaging. Patients and caregivers also saw information in the PHR as a useful memory tool given their visits to multiple doctors. Providers had reservations about patients viewing raw data, which they were not prepared to interpret or might be inaccurate; patients and caregivers did not express any reservations about having access to more information. Patients saw PHR communication functions as a potential tool for relationship building. Patients and caregivers valued the journal as a tool for reflection and delivery of emotional support. Providers felt the PHR would facilitate patient-physician communication but worried that sharing journal access would make the doctor-patient relationship less professional and had reservations about the time burden of reviewing. Strategies suggested for efficient adoption into workflow included team delegation. Establishment of parameters for patient uses and provider responses was perceived as good standard practice.

CONCLUSIONS

PHR perceptions differed by role, with providers seeing the PHR as informational, while patients and caregivers viewed the tool as more relational. Personal health records should be linked to electronic health records for ease of use. Tailoring access, content, and implementation of the PHR is essential. Technology changes have the potential to change the nature of the patient-physician relationship. Patients and providers should establish shared expectations about the optimal use of the PHR and explore how emerging patient-centered technologies can be successfully implemented in modern medical practice to improve the relational quality of care.

Preoperative short-course radiotherapy followed by consolidation chemotherapy for treatment with locally advanced rectal cancer: a meta-analysis

Background

The addition of consolidation chemotherapy to preoperative short-course radiotherapy during the prolonged interval between the completion of radiation and surgery in locally advanced rectal cancer (LARC) could enhance pathologic response and might act on potential micrometastasis. We performed this meta-analysis to evaluate whether short-course radiotherapy followed by consolidation chemotherapy (SCRT/CCT) could be a neoadjuvant treatment option compared with conventional long-course chemoradiotherapy (LCCRT).

Methods

We searched the PubMed, EMBASE, MEDLINE, and Cochrane Library databases. The primary endpoints were pathological outcomes, and the secondary endpoints included survival rate, sphincter preservation rate, R0 resection rate and toxicity. RevMan 5.3 was used to calculate pooled risk ratio (RRs) and 95% confidence intervals (CIs).

Results

A total of seven eligible studies and 1865 participants were included in this meta-analysis. Compared with the LCCRT, SCRT/CCT increased pathologic complete response (pCR) rate [RR = 1.74, 95% CI (1.41, 2.15), P < 0.01] and led to a lower proportion of patients with adjuvant pathologic tumor stage 3–4 (ypT3-4) disease [RR = 0.88, 95% CI (0.80, 0.97), P = 0.01] or lymph node positive (ypN +) disease [RR = 0.83, 95% CI (0.71, 0.98), P = 0.02]. In addition, the disease-free survival (DFS) was better in SCRT/CCT group [RR = 1.10, 95% CI (1.02, 1.18), P = 0.01], while overall survival rate and toxicity and surgical procedures were similar between two groups.

Conclusion

Based on better pathological outcomes and DFS in SCRT/CCT group, we recommended preoperative short-course radiotherapy followed by consolidation chemotherapy as the optional neoadjuvant treatment for LARC.

A Prognostic Nomogram for T3N0 Rectal Cancer After Total Mesorectal Excision to Help Select Patients for Adjuvant Therapy

Background

The recurrence rate of T3N0 rectal cancer after total mesorectal excision (TME) is relatively low, meaning that not all patients need adjuvant therapy (AT) (radiotherapy, chemotherapy, or chemoradiotherapy).

Methods

Patients diagnosed with pT3N0M0 rectal cancer after TME were analyzed using the SEER database, of which 4367 did not receive AT and 2794 received AT. Propensity score matching was used to balance the two groups in terms of confounding factors. Cox proportional hazards regression analysis was used to screen independent prognostic factors, which were then used to establish a nomogram. The patients were then divided into three groups with X-tile software according to their risk scores. We enrolled 334 patients as external validation.

Results

The C-index of the model was 0.725 (95% confidence interval: 0.694–0.756). We divided the patients into three different risk layers based on the nomogram prediction scores, and found that AT did not improve the prognosis of low- and moderate-risk patients, while high-risk patients benefited from AT. External validation data also support the above conclusions.

Conclusion

This study developed a nomogram that effectively and comprehensively evaluates the prognosis of T3N0 rectal cancer patients after TME. After using the nomogram, we recommend AT for high-risk patients, but not for low- and moderate-risk patients.

Trends in the use of short-course radiation therapy for rectal cancer in New South Wales, Australia

INTRODUCTION

Trends in the use of short-course radiation therapy (RT) for rectal cancer in Australia are unknown. The purpose of this study was to compare short-course RT and long-course chemoradiation (CRT) utilisation in the neoadjuvant treatment of rectal cancer in New South Wales (NSW).

METHODS

Patients who received neoadjuvant RT (2009-2014) for rectal cancer were identified from the NSW Central Cancer Registry. Univariate and multivariable analyses were performed to investigate factors associated with receipt of short-course RT.

RESULTS

A total of 1196 (81%) patients received long-course CRT, and 274 (19%) patients received short-course RT. Receipt of short-course RT was associated with older age: 54% in patients ≥80 years, and 11% in patients <50 years (P < 0.0001). Patients with T2 disease (30%) were more likely to receive short-course RT, compared with T3 (19%) or T4 (8%) disease (P = 0.002). Patients with N0 (23%) disease were more likely to be treated with short-course RT, compared with N+ (16%) (P = 0.03). The proportion of short-course RT delivered to patients with Charlson Comorbidity Index (CCI) ≥ 2 (28%) was higher than patients with CCI = 0 (17%) (P = 0.002). There was wide variation in the proportion of short-course RT used across residence local health districts (5-29%) (P < 0.0001).

CONCLUSION

In rectal cancer patients treated with neoadjuvant RT in NSW, 19% received short-course RT. The use of short-course RT was associated with older age, comorbidities and less advanced disease. Wide variation across NSW was identified and future research investigating factors for the variation will be useful.

Radiotherapy regimens for rectal cancer: long-term outcomes and health-related quality of life in the Stockholm III trial

BACKGROUND

The Stockholm III trial randomly assigned 840 patients to short-course radiotherapy of 5 × 5 Gy with surgery within 1 week (SRT), short-course radiotherapy of 5 × 5 Gy with surgery after 4-8 weeks (SRT-delay), or long-course radiotherapy of 25 × 2 Gy with surgery after 4-8 weeks (LRT-delay). This study details the long-term oncological outcomes and health-related quality of life (HRQoL).

METHODS

Patients with biopsy-proven resectable adenocarcinoma of the rectum were included. Primary outcome was time to local recurrence (LR), and secondary endpoints were distant metastases (DMs), overall survival (OS), recurrence-free survival (RFS), and HRQoL. Patients were analysed in a three-arm randomization and a short-course radiotherapy comparison.

RESULTS

From 1998 to 2013, 357, 355, and 128 patients were randomized to the SRT, SRT-delay, and LRT-delay groups respectively. Median follow-up time was 5.7 (range 5.3-7.6) years. Comparing patients in the three-arm randomization, the incidence of LR was three of 129 patients, four of 128, and seven of 128, and DM 31 of 129 patients, 38 of 128, and 38 of 128 in the SRT, SRT-delay, and LRT-delay groups respectively. In the short-course radiotherapy comparison, the incidence of LR was 11 of 357 patients and 13 of 355, and DM 88 of 357 patients and 82 of 355 in the SRT and SRT-delay groups respectively. No comparisons showed statistically significant differences. Median OS was 8.1 (range 6.9-11.2), 10.3 (range 8.2-12.8), and 10.5 (range 7.0-11.3) years after SRT, SRT-delay, and LRT-delay respectively. Median OS was 8.1 (range 7.2-10.0) years after SRT and 10.2 (range 8.5-11.7) years after SRT-delay. There were no statistically significant differences in HRQoL.

CONCLUSION

After a follow-up of 5 years, delaying surgery for 4-8 weeks after radiotherapy treatment with 5 × 5 Gy was oncologically safe. Long-term HRQoL was similar among the treatment arms.

TRIAL REGISTRATION NUMBER

NTC00904813.

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.

[Radiation Oncology - Recent Status]

Radiation Oncology - Recent Status Abstract. We summarize the most important developments and innovations in the field over the past years and illustrate resulting external radiation treatment schedules and related treatment tolerance, focusing on hypofractionation.

Neoadjuvant Modified Short-Course Radiotherapy Followed by Delayed Surgery for Locally Advanced Rectal Cancer

Simple Summary

Both short- and long-course neoadjuvant radiotherapy (NA-RT) followed by surgery have been adopted as standard treatments for locally advanced rectal cancer (LARC). We hypothesized that a modified short-course radiotherapy (mSC-RT) using an accelerated hyperfractionated regimen, with a dose of 2.5 Gy twice daily up to a total dose of 25 Gy in 10 fractions, can provide a favorable therapeutic ratio in comparison with the conventional regimens. Ninety-seven consecutive LARC patients undergoing mSC-RT followed by delayed surgery were analyzed in this retrospective study. Additionally, potential prognostic factors for overall survival (OS) were also assessed. The results showed that mSC-RT followed by delayed surgery achieved equivalent anti-tumor efficacy and acute toxicity that were comparable with long- and short-course NA-RT, respectively. A neutrophil-to-lymphocyte ratio (NLR) ≥ 1.83 was independently associated with poor OS in LARC patients receiving mSC-RT. Thus, mSC-RT can be a promising alternative to both standard long- and short-course NA-RT regimens.

Abstract

This study aimed to assess the clinical outcomes and predictive factors of neoadjuvant modified short-course radiotherapy (mSC-RT) for locally advanced rectal cancer (LARC). Data from 97 patients undergoing mSC-RT followed by radical surgery for LARC were retrospectively analyzed. A 2.5 Gy dose twice daily up to a total dose of 25 Gy in 10 fractions was administered through mSC-RT, and this was delivered with oral chemotherapy in 95 (97.9%) patients. Radical surgery was performed 6 (range, 3–13) weeks after mSC-RT. The median follow-up among surviving patients was 43 (8–86) months. All patients completed neoadjuvant radiotherapy with no acute toxicity grade ≥ 3. Three- and five-year local control rates were 96.3% and 96.3%, respectively. Three- and five-year overall survival (OS) rates were 92.7% and 79.8%, respectively. Univariate analyses revealed that poor OS was associated with no concurrent administration of capecitabine, C-reactive-protein-to-albumin ratio ≥ 0.053, carcinoembryonic antigen ≥ 3.4 ng/mL, and neutrophil-to-lymphocyte ratio (NLR) ≥ 1.83 (P = 0.045, 0.001, 0.041, and 0.001, respectively). Multivariate analyses indicated that NLR ≥ 1.83 was independently associated with poor OS (p = 0.018). mSC-RT followed by delayed surgery for LARC was deemed feasible and resulted in good clinical outcomes, whereas poor OS was associated with high NLR.

CD133 Expression Predicts Relapse in Patients With Locally Advanced Rectal Cancer Treated With Neoadjuvant Chemotherapy

AIM

The aim of the present study was to explore the association between CD133 expression and postoperative relapses in patients with locally advanced rectal cancer (LARC) who received neoadjuvant chemotherapy (NAC).

PATIENTS AND METHODS

We retrospectively examined 52 patients with LARC (cT3-4, Nany, M0) who received oxaliplatin-based NAC before surgery. CD133 expression was evaluated using immunohistochemistry and divided into low and high expression groups.

RESULTS

High CD133 expression was observed in 22 patients (42.3%). Patients with high CD133 expression had more frequent vessel invasion and relapse than those with low CD133 expression (p=0.013 and p=0.036, respectively). Comparing the low with high CD133 expression groups, the 4-year relapse-free survival rates were 82.2% vs. 46.3% (p=0.009). Multivariate analysis indicated that CD133 expression was an independent risk factor for relapse (HR=3.138; 95%CI=1.046-9.412; p=0.041).

CONCLUSION

CD133 expression may be a predictive biomarker for postoperative relapse in patients with LARC who received NAC before surgery.

Initial experience of preoperative short-course radiotherapy followed by oxaliplatin-based consolidation chemotherapy for locally advanced rectal cancer

PURPOSE

We analyzed the safety and feasibility of preoperative short-course radiotherapy (SCRT) followed by consolidation chemotherapy for patients with locally advanced rectal cancer (LARC).

METHODS

From April 2018 to May 2019, 19 patients with LARC were treated with SCRT followed by three cycles of consolidation chemotherapy with leucovorin, fluorouracil, and oxaliplatin (FOLFOX6) before surgery. Adjuvant chemotherapy relied on oxaliplatin. Tumor response, patient compliance, and toxicities were analyzed.

RESULTS

The median age was 60 years (range 44-71), and 16 of the patients were male. The median tumor height was 5 cm (range 0-9) from anal verge. All patients received a total dose of 25 Gy in five fractions. The number of cycles of FOLFOX6 before surgery was three in 17, four in one, five in one. Five patients required dose reductions in consolidation chemotherapy. The median interval between initiation of SCRT and surgery was 10.6 weeks (range 8.6-16.4). A pathologic complete response was seen in two patients (11%). Grade III toxicities to the preoperative treatment were seen in five patients (26%): diarrhea in two, a decreased white blood cell count in one, and anemia in two. Postoperative complications arising within 30 days developed in five patients (26%). During the median follow-up period of 20.4 months, there was no tumor recurrence.

CONCLUSION

Preoperative SCRT followed by oxaliplatin-based consolidation chemotherapy showed acceptable toxicity and feasibility in patients with LARC. Prospective randomized trials are warranted to verify the efficacy and safety of this treatment strategy compared with conventional long-course concurrent chemoradiotherapy.

Short course radiotherapy and delayed surgery for locally advanced rectal cancer in frail patients: is it a valid option?

OBJECTIVE

The endpoint of the present study was to evaluate the outcomes of short-course radiotherapy (SCRT) and SCRT with delayed surgery (SCRT-DS) on a selected subgroup of frail patients with locally advanced middle/low rectal adenocarcinoma.

METHODS

From January 2008 to December 2018, a total of 128 frail patients with locally advanced middle-low rectal adenocarcinoma underwent SCRT and subsequent restaging for eventual delayed surgery. Rates of complete pathological response, down-staging, disease free survival (DFS) and overall survival (OS) were analyzed.

RESULTS

128 patients completed 5 × 5 Gy pelvic radiotherapy. 69 of these were unfit for surgery; 59 underwent surgery 8 weeks (average time: 61 days) after radiotherapy. Downstaging of T occurred in 64% and down-staging of N in 50%. The median overall survival (OS) of SCRT alone was 19.5 months. The 1-year, 2-year, 3-year and 5-year OS was 48%, 22%, 14% and 0% respectively. In the surgical group, the median disease-free survival (DFS) and median OS were, respectively, 67 months (95% CI 49.8-83.1 months) and 72.1 months (95% CI 57.5-86.7 months). The 1, 2, 3, 5-year OS was 88%, 75%, 51%, 46%, respectively. Post-operative morbidity was 22%, mortality was 3.4%.

CONCLUSIONS

Frail patients with advanced rectal cancer are often "unfit" for long-term neoadjuvant chemoradiation. A SCRT may be considered a valid option for this group of patients. Once radiotherapy is completed, patients can be re-evaluated for surgery. If feasible, SCRT and delayed surgery is the best option for frail patients.

Prognostic impact of at least 12 lymph nodes after neoadjuvant therapy in rectal cancer: A meta-analysis

BACKGROUND

The number of dissected lymph nodes (LNs) in rectal cancer after neoadjuvant therapy has a controversial effect on the prognosis.

AIM

To investigate the prognostic impact of the number of LN dissected in rectal cancer patients after neoadjuvant therapy.

METHODS

We performed a systematic review and searched PubMed, Embase (Ovid), MEDLINE (Ovid), Web of Science, and Cochrane Library from January 1, 2000 until January 1, 2020. Two reviewers examined all the publications independently and extracted the relevant data. Articles were eligible for inclusion if they compared the number of LNs in rectal cancer specimens resected after neoadjuvant treatment (LNs ≥ 12 vs LNs < 12). The primary endpoints were the overall survival (OS) and disease-free survival (DFS).

RESULTS

Nine articles were included in the meta-analyses. Statistical analysis revealed a statistically significant difference in OS [hazard ratio (HR) = 0.76, 95% confidence interval (CI): 0.66-0.88, I² = 12.2%, P = 0.336], DFS (HR = 0.76, 95%CI: 0.63-0.92, I² = 68.4%, P = 0.013), and distant recurrence (DR) (HR = 0.63, 95%CI: 0.48-0.93, I² = 30.5%, P = 0.237) between the LNs ≥ 12 and LNs < 12 groups, but local recurrence (HR = 0.67, 95%CI: 0.38-1.16, I² = 0%, P = 0.348) showed no statistical difference. Moreover, subgroup analysis of LN negative patients revealed a statistically significant difference in DFS (HR = 0.67, 95%CI: 0.52-0.88, I² = 0%, P = 0.565) between the LNs ≥ 12 and LNs < 12 groups.

CONCLUSION

Although neoadjuvant therapy reduces LN production in rectal cancer, our data indicate that dissecting at least 12 LNs after neoadjuvant therapy may improve the patients’ OS, DFS, and DR.

Targeted Delivery of DNA Framework-Encapsulated Native Therapeutic Protein into Cancer Cells

A protein-based therapy is significantly challenged by the successful delivery of native proteins into the targeted cancer cells. We address this challenge here using an all-sealed divalent aptamer tetrahedral DNA framework (asdTDF) delivery platform, in which the protein drug is encapsulated inside the cavity of the framework stoichiometrically via a reversible chemical bond. The ligase-assisted seal of the nicks results in highly enhanced TDF stability of the against nuclease digestion to effectively protect the therapeutic protein from degradation. In addition, the divalent aptamer sequences incorporated into the framework favor it with a target-specific and efficient delivery capability. Importantly, upon being readily delivered into the targeted cancer cells, endogenous glutathione can trigger the release of the native therapeutic protein from the TDF in a traceless fashion by cleaving the reversible chemical bond, thereby leading to effective apoptosis of the specific cancer cells.

Rectal prolapse following short-course radiotherapy for rectal cancer: report of a case

Palliative short-course radiotherapy may be considered as an alternative to abdominoperineal resection in elderly patients with advanced rectal cancer.

A 92-year-old woman was diagnosed with a rectal prolapse after short-course radiotherapy; 2 months before she was diagnosed with advanced lower rectal cancer. A curative approach was declined. Therefore, a palliative short-course radiotherapy followed. Two weeks after termination of radiotherapy, a symptomatic rectal prolapse has been observed. Endoscopy confirmed a tumor completely included in the prolapsing rectum. A rectal prolapse resection by Altemeier’s technique was performed. Histological examination downgraded the tumor staging to ypT1 M0.

This case discusses whether the prolapse was preexisting and led to overstaging the tumor or whether the prolapse is a new-onset complication of the radiotherapy.

It seems of paramount importance to detect preexisting rectal prolapse to avoid overstaging. If presumed rectal prolapse was not present before therapy, rectal prolapse may represent a new-onset adverse event of short-course radiotherapy.

Should Short-Course Neoadjuvant Radiation Therapy Be Applied for Low-Lying Rectal Cancer? A Systematic Review and Meta-Analysis of the Randomized Trials

PURPOSE

National Comprehensive Cancer Network guidelines recommend either long-course chemoradiation (LC) or short-course radiation (SC, 5 × 5 Gy) for rectal cancer before total mesorectal excision. However, they do not recommend SC for low-lying tumors. As early toxicity of SC is lower than that of LC, and postoperative complications as well as late toxicity are similar, the probable reason is a notion that for low-lying tumors LC may be more effective than SC in assuring local control.

METHODS AND MATERIALS

A systematic review and meta-analysis of the randomized trials comparing SC with LC was performed to test the hypothesis that for low-lying tumors, LC is superior to SC in reducing the risk of local failure.

RESULTS

The systematic search identified 4 trials including, in total, 421 patients with tumors <5 cm from the anal verge; 221 were randomized to SC and 200 to LC. The meta-analysis showed that the difference in local failure rate between SC and LC was insignificant; the pooled odds ratio was 0.87, 95% confidence interval 0.53 to 1.44, P = .59. Heterogeneity between trials was insignificant; I² = 0.0%, P = .47.

CONCLUSIONS

Our meta-analysis does not support the notion that LC given before total mesorectal excision is superior to SC in reducing the risk of local failure in low-lying tumors.

Metformin as an Alternative Radiosensitizing Agent to 5-Fluorouracil During Neoadjuvant Treatment for Rectal Cancer

BACKGROUND

Neoadjuvant chemoradiation for locally advanced rectal cancer combining 5-fluorouracil with radiation increases tumor regression compared with radiation alone. However, it occurs at the cost of significant treatment-related toxicity. Patients with rectal cancer using metformin have been associated with improved response to radiotherapy.

OBJECTIVE

The purpose of this study was to evaluate the radiosensitizing effects of metformin in vitro and in vivo and compare it with a standard combination of radiation/5-fluorouracil.

DESIGN

Colorectal cancer cell lines SW480, HT29, and HCT116 were used as models. Cell viability was compared under treatments with radiation, radiation/5-fluorouracil, metformin, radiation/metformin, and radiation/5-fluorouracil/metformin. Nude mice were injected subcutaneously with SW480 cells and treated for 1 week with radiation/5-fluorouracil, metformin, radiation/metformin, or radiation/5-fluorouracil/metformin. Tumor volume was evaluated for 4 weeks after treatment completion. The phosphorylation status of key proteins of the PI3K/Akt/mTOR pathway was determined by immunoblots.

SETTINGS

This was an experimental study conducted in vitro and in vivo.

PATIENTS

Animal models/cell lines were used.

MAIN OUTCOME MEASURES

The end point was to investigate how metformin compares with 5-fluorouracil as a radiosensitizer.

RESULTS

All cell lines significantly decreased cell viability after treatment with radiation/metformin when compared with radiation alone. Radiation/metformin was superior to radiation/5-fluorouracil in SW480 (37% vs 74%; p < 0.001). In HT29 and in HCT116, radiation/metformin was inferior to radiation/5-fluorouracil (40.0% vs 13.8%, p < 0.001 and 40.0% vs 7.0%, p < 0.001), mainly because of increased 5-fluorouracil toxicity (≤20% of cell viability). In vivo assays indicated that radiation/metformin treatment was comparable with radiation/5-fluorouracil (557 vs 398 mm; p > 0.05) and that the addition of metformin to the standard radiation/5-fluorouracil did not improve tumor response (349 mm; p > 0.05). Metformin exerted strong PI3K/Akt/mTOR pathway inactivation effects after 24-hour exposure (increasing pAMPK, p < 0.01; decreasing pAkt, p < 0.01; and pS6, p <0.05).

LIMITATIONS

In vitro and in vivo chemoradiation regimens cannot be directly translated to human delivery methods.

CONCLUSIONS

Metformin enhances tumor response to radiation in vitro and in vivo. Metformin is an attractive alternative radiosensitizing agent to be considered in future studies/trials. See Video Abstract at http://links.lww.com/DCR/B219. LA METFORMINA COMO AGENTE RADIOSENSIBILIZADOR ALTERNATIVO A 5FU DURANTE EL TRATAMIENTO NEOADYUVANTE PARA CÁNCER DE RECTO: La quimiorradiación neoadyuvante para el cáncer de recto localmente avanzado que combina 5FU con radiación aumenta la regresión tumoral en comparación con la radiación sola. Sin embargo, se produce a costa de una toxicidad significativa relacionada con el tratamiento. Los pacientes con cáncer de recto que usan metformina se han asociado con una mejor respuesta a la radioterapia.Evaluar los efectos radiosensibilizantes de metformina in vitro e in vivo y compararlo con la combinación estándar de radiación / 5FU.Se usaron como modelos las líneas celulares de cáncer colorrectal SW480, HT29 y HCT116. La viabilidad celular se comparó en tratamientos con radiación, radiación / 5FU, metformina, radiación / metformina y radiación / 5FU / metformina. A los ratones desnudos se les inyectó por vía subcutánea células SW480 y fueron tratados durante una semana con radiación / 5FU, metformina, radiación / metformina o radiación / 5FU / metformina. El volumen tumoral se evaluó durante 4 semanas después de la finalización del tratamiento. El estado de fosforilación de las proteínas clave de la vía PI3K / Akt / mTOR se determinó mediante inmunotransferencias.Estudio experimental in vitro e in vivo.Modelo animal / líneas celulares.El punto final fue investigar cómo la metformina se compara con 5FU como un radiosensibilizador.Todas las líneas celulares disminuyeron significativamente la viabilidad celular después del tratamiento con radiación / metformina en comparación con la radiación sola. La radiación / metformina fue superior a la radiación / 5FU en SW480 (37% frente a 74%; p <0,001). En el HT29 y el HCT116 la radiación / metformina fue inferior a la radiación / 5FU (40% vs 13.8%, p <0.001 y 40% vs 7%, p <0.001; respectivamente), debido principalmente al aumento de la toxicidad de 5FU (≤20% de la célula viabilidad). Los ensayos in vivo indicaron que el tratamiento con radiación / metformina era comparable a la radiación / 5FU (557 vs 398 mm, p > 0.05), y que la adición de metformina a la radiación estándar / 5FU no mejoró la respuesta tumoral (349 mm, p > 0.05). La metformina ejerció fuertes efectos de inactivación de la vía PI3K / Akt / mTOR después de 24 horas de exposición (aumentando pAMPK p < 0.01, disminuyendo pAkt, p < 0.01; y pS6, p < 0.05).Los regímenes de CRT in vitro e in vivo no se pueden traducir directamente a los métodos de entrega en humanos.La metformina mejora la respuesta tumoral a la radiación in vitro e in vivo. La metformina es un agente alternativo de radiosensibilización atractivo para ser considerado en futuros estudios / ensayos. Consulte Video Resumen en http://links.lww.com/DCR/B219. (Traducción-Dr Gonzalo Hagerman).

A phase 1 trial of the safety, tolerability and biological effects of intravenous Enadenotucirev, a novel oncolytic virus, in combination with chemoradiotherapy in locally advanced rectal cancer (CEDAR)

BACKGROUND

Chemoradiotherapy remains the standard of care for locally advanced rectal cancer. Efforts to intensify treatment and increase response rates have yet to yield practice changing results due to increased toxicity and/or absence of increased radiosensitization. Enadenotucirev (EnAd) is a tumour selective, oncolytic adenovirus which can be given intravenously. Pre-clinical evidence of synergy with radiation warrants further clinical testing and assessment of safety with radiation.

METHODS

Eligibility include histology confirmed locally advanced rectal cancer that require chemoradiation. The trial will use a Time-to-Event Continual Reassessment Model-based (TiTE-CRM) approach using toxicity and efficacy as co-primary endpoints to recommend the optimal dose and treatment schedule 30 patients will be recruited. Secondary endpoints include pathological complete response the neoadjuvant rectal score. A translational program will be based on a mandatory biopsy during the second week of treatment for 'proof-of-concept' and exploration of mechanism. The trial opened to recruitment in July 2019, at an expected rate of 1 per month for up to 4 years.

DISCUSSION

Chemoradiation with Enadenotucirev as a radiosensitiser in locally Advanced Rectal cancer (CEDAR) is a prospective multicentre study testing a new paradigm in radiosensitization in rectal cancer. The unique ability of EnAd to selectively infect tumour cells following intravenous delivery is an exciting opportunity with a clear translational goal. The novel statistical design will make efficient use of both toxicity and efficacy data to inform subsequent studies.

TRIAL REGISTRATION

ClinicalTrial.gov, NCT03916510. Registered 16th April 2019.

COVID-19: hypofractionation in the Radiation Oncology Department during the 'state of alarm': first 100 patients in a private hospital in Spain

During the COVID-19 pandemic, Spain declared a ‘state of alarm’ on 14 March 2020. In our Radiation Oncology Department, experienced in administering hypofractionated treatments (partial irradiation in breast cancer, moderate hypofractionation in localized prostate cancer, etc), we have increased the hypofractionated treatment indications. We are only deferring the start of non-urgent treatments such as prostate tumours under androgen deprivation or benign brain tumours which are candidates for radiosurgery such as meningiomas or acoustic neuroma.

In this hypofractionation era we find that we have decreased the number of sessions per patient and that we can evaluate the last years with the fractionation index (FI) (calculated by dividing the total number of fractions administered in the department by the total number of patients treated). We have gone from 14.4 in 2018 to 13.78 in 2019, excluding brachytherapy.

We report the results of the first 100 patients who have experienced radiotherapy treatment since the state of alarm (66 women and 34 men). In these patients, the FI is 12.12—lower than previous years.

Clinical Implementation of Preoperative Short-Course Pencil Beam Scanning Proton Therapy for Patients With Rectal Cancer

Purpose

For treatment of rectal cancer, pencil beam scanning proton therapy (PBS-PT) may reduce radiation exposure to normal tissues compared with 3-dimensional conformal photon radiation therapy (3DCRT) or volumetric modulated arc photon radiation therapy (VMAT). The purpose of this study was to report the clinical implementation and dosimetric analysis of preoperative short-course PBS-PT for rectal cancer.

Methods and Materials

Eleven patients with stage IIA-IVB rectal cancer received preoperative short-course (25 Gy in 5 fx) PBS-PT between 2018 and 2019 preceding curative-intent total mesorectal excision. PBS-PT plans were generated using single-field optimization with 2 posterior-oblique fields. Verification computed tomography scans were performed on the first 3 days of treatment. Each patient had a backup 3DCRT and VMAT plan.

Results

Clinical target volume coverage was similar between PBS-PT, 3DCRT, and VMAT. PBS-PT had statistically significant reductions in dose to the small bowel, large bowel, bladder, and femoral heads across multiple dosimetric parameters. All patients completed PBS-PT as planned without need for replanning. All computed tomography verification scans demonstrated good target coverage with clinical target volume V100 > 95%.

Conclusions

Preoperative short-course PBS-PT has been successfully implemented and offers a significant reduction of dose to normal tissues. Prospective studies are warranted to evaluate if dosimetric advantages translate into clinical benefit.

Altered fractionation short-course radiotherapy for stage II-III rectal cancer: a retrospective study

Purpose

To report the long-term outcomes of neoadjuvant altered fractionation short-course radiotherapy in 271 consecutive patients with stage II-III rectal cancer.

Patients and Methods: This was a retrospective single institution study with median follow-up of 101 months (8.4 years). Patients who were alive at the time of analysis in 2018 were contacted to obtain functional outcome data (phone interview). Radiotherapy consisted of 25 Gy in 10 fractions of 2.5 Gy administered twice daily. Median time interval to surgery was 5 days.

Results

Local relapse was observed in 12 patients (4.4%) after a median of 28 months. Overall survival after 5 and 10 years was 73 and 55.5%, respectively (corresponding disease-free survival 65.5 and 51%). Of all patients without permanent stoma, 79% reported no low anterior resection syndrome (LARS; 0–20 points), 9% reported LARS with 21–29 points and 12% serious LARS (30–42 points).

Conclusion

The present radiotherapy regimen was feasible and resulted in low rates of local relapse. Most patients reported good functional outcomes.

Comparison of long course and short course preoperative radiotherapy in the treatment of locally advanced rectal cancer: a systematic review and meta-analysis

BACKGROUND

rectal cancer (RC) is one of the most prevalent malignancies worldwide and different preoperative radiotherapies may lead to different outcomes. This meta-analysis aimed to compare the effectiveness of long-course (LC) and short-course radiotherapy (SC), with or without chemotherapy, for locally advanced rectal cancer.

METHODS

studies published up to March 31st 2018 were retrieved from PubMed, Medline, Cochrane and EMABSE. Randomized control or consort control trials that reported the outcomes of short or long course radiotherapy were eligible. Either a fixed or random effects model was used to access the overall combined risk estimates.

RESULTS

sixteen studies with a total of 2,773 RC patients were included in the analysis. There were no significant differences between LC and SC therapies with regard to the following: pathological complete response (PCR) (I2 = 78%, p < 0.05, RR = 0.54, 95% CI: 0.26-1.10); tumor downstaging (I2 = 79%, p < 0.05, RR = 0.83, 95% CI: 0.58-1.17); local recurrences (I2 = 22%, p = 0.27, RR = 0.55, 95% CI: 0.26-1.16); distant metastases (I2 = 29%, p = 0.22, RR = 1.03, 95% CI: 0.77-1.37); mortality (I2 = 0%, p = 0.78, RR = 0.95, 95% CI: 0.78-1.15) and serious late toxicity (I2 = 74%, p = 0.01, RR = 1.10, 95% CI: 0.37-3.26). In the subgroup analysis, LC had a better PCR and tumor downstaging rate compared with SC in the RCT subgroup. Besides, LC also presented a better PCR rate compared with SC without chemotherapy.

CONCLUSIONS

LC and SC are both effective in the preoperative treatment of RC with regard to PCR, tumor downstaging, local recurrences, distant metastases, mortality and serious late toxicity. Furthermore, chemotherapy may enhance the efficacy of preoperative treatment.

Dose-time fractionation schedules of preoperative radiotherapy and timing to surgery for rectal cancer

Chemoradiotherapy (CRT) is extensively used prior to surgery for rectal cancer to provide significantly better local control, but the radiotherapy (RT), as the other component of CRT, has been subject to less interest than the drug component in recent years. With considerable developments in RT, the use of advanced techniques, such as intensity-modulated radiotherapy (IMRT) in rectal cancer, is garnering more attention nowadays. The radiation dose can be better conformed to the target volumes with possibilities for synchronous integrated boost without increased complications in normal tissue. Hopefully, both local recurrence and toxicities can be further reduced. Although those seem to be of interest, many issues remain unresolved. There is no international consensus regarding the radiation schedule for preoperative RT for rectal cancer. Moreover, an enormous disparity exists regarding the RT delivery. With the advent of IMRT, variations will likely increase. Moreover, time to surgery is also quite variable, as it depends upon the indication for RT/CRT in the clinical practices. In this review, we discuss the options and problems related to both the dose-time fractionation schedule and time to surgery; furthermore, it addresses the research questions that need answering in the future.