Should we favour the use of 5 × 5 preoperative radiation in rectal cancer

The effect of Inc parameter on VMAT radiotherapy plans quality for rectal cancer using Monaco TPS

BACKGROUND

To investigate the effect of the Increment of gantry angle (Inc) parameter setting of the Monaco Treatment planning system (Monaco TPS) on the dosimetry and quality parameters of the volumetric modulated arc therapy (VMAT) program for rectal cancer.

METHODS

A retrospective analysis was conducted on 50 patients with rectal cancer who underwent intensity modulated radiation therapy using the Monaco TPS system from 2020 to 2021. Under the same optimization function configuration and other parameter settings, the Inc parameters in the VMAT radiotherapy plan were set to 10°, 20°, 30°, and 40°. The dose-volume histogram (DVH) was used to evaluate the dose distribution of the target area and the radiation dose of the organs at risk (OAR). The differences in the dosimetry of the planning target volume (PTV) and OAR, as well as the gamma pass rate (GPR) were compared.

RESULTS

In terms of target dose, D98, Dmin, HI, and conformity index (CI) of Inc10 group was significantly lower than those of Inc20, 30, and 40 groups (P < 0.05), and D2 of Inc10 group was significantly higher than that of Inc20 group (P = 0.009). We also found CI of Inc20 and 30 were significantly better than that of Inc40 (both P < 0.05). In terms of OAR dose, the study found that the Dmean, Dmin, V50%, V45%, and V40% for the bladder of the Inc10 group were lower than those of the other groups (all P < 0.05), the Dmean for femoral head of the Inc20 group was lower than that of the Inc30 group (P < 0.05), and Inc20 showed a better protective effect on the femoral head. The MUs tend to decrease as the Inc parameter setting is increased. The monitor unit (MU) in Inc10 group were significantly higher than those in Inc20, Inc30, and Inc40 groups, and the MU of Inc20 group was significantly higher than that of Inc40 group (both P < 0.05). We found that for the 3%/3 mm and 2%/2 mm standards, the GPRs of each plan were > 90%, which met clinical requirements.

CONCLUSIONS

Different settings of Inc parameters have varying degrees of impact on target dose, OAR dose, and machine MU. It is important for doctors to choose different Inc parameters according to different clinical needs.

Short-course radiotherapy for rectal cancer: real-world evidence in Argentina

Background

Short-course radiotherapy (SCRT) of 25 Gy in five daily fractions is a recommended strategy in the neoadjuvant setting for resectable locally advanced rectal cancer (LARC), as well as in cases of metastatic disease for local control. There is scarce information regarding the use of SCRT for patients who have received nonoperative management.

Objectives

To describe the characteristics of patients who received treatment with SCRT for LARC and metastatic rectal cancer, toxicity, and the approach after radiation treatment.

Methods

This is a retrospective analysis of all patients who underwent SCRT for rectal cancer at the Alexander Fleming Institute from March 2014 to June 2022.

Results

In total, 44 patients were treated with SCRT. The majority were male (29, 66%), with a median age of 59 years (interquartile range 46-73). Most patients had stage IV disease (26, 59.1%), followed by LARC (18, 40.9%). Most lesions were located in the middle rectum (30, 68%). The majority of LARC patients underwent SCRT followed by consolidation chemotherapy (ChT) (16/18, 89%), while most patients with metastatic disease underwent SCRT followed by consolidation ChT (14/26, 53.8%). A clinical complete response (cCR) was documented in 8/44, 18.2% of patients. Most patients with LARC and cCR were managed by a watch and wait approach (5/18, 27.7%). Local recurrence was observed in LARC cases (2/18, 11.1%). Patients who underwent SCRT following consolidation ChT were more likely to have adverse events (AEs) than those undergoing induction ChT following SCRT (11/30, 36.7% versus 3/12, 25%, p = 0.02).

Conclusion

In a subgroup of patients diagnosed with LARC and treated with SCRT followed by ChT, surgical treatment could be omitted after they achieved a cCR. Local recurrence was similar to that reported in a previous study. SCRT is a reasonable option for local disease control in stage IV disease, yielding low toxicity rates. Therefore, decisions must be made by a multidisciplinary team. Prospective studies are necessary to reach further conclusions.

The in-silico feasibility of dose escalated, hypofractionated radiotherapy for rectal cancer

Background and purpose

Short course radiotherapy (SCRT) has a low biological prescription dose. Rectal cancer has a dose response relationship and moderate α/β ratio (∼5). We hypothesise hypofractionated dose escalation has radiobiological advantages. We assessed in-silico dose escalation to the primary tumour using a simultaneous integrated boost (SIB) technique.

Materials and methods

Patients who had received 25 Gy/5# were enrolled. GTV was macroscopic tumour including lumen. CTVA was GTV + 10 mm. CTVB included elective nodes. PTV_Low was created from CTVF (CTVA + CTVB) + 7 mm. PTV_High (SIB) was GTV + 5 mm margin. OAR were as per RTOG guidelines. Each patient had 4 plans created at increasing dose levels (27.5 Gy, 30 Gy, 32.5 Gy and 35 Gy) to PTV_High. PTV_Low was 25 Gy/5#.5 test plans were created for each patient in Eclipse™ v15.5 and consisted of 2 VMAT full arcs (6 MV), Varian Truebeam (2.7). Planning objectives were set in the Photon optimiser (PO) and recalculated using Acuros v15.5. A priori feasibility was defined as 90% of plans achieving the planning objectives at 32.5 Gy dose level (EqD2 53.4 Gy).

Results

20 SCRT patients median age 70, F (n = 5), M (n = 15). Rectum level; low (n = 12), mid (n = 3) and upper (n = 5). 100 plans were analysed. Mean volume of PTV_High was 130 cm3 (SD 81.5) and PTV_Low 769.6 cm3 (SD 241.1). 100% plans complied with mandatory planning dose metrics for each structure at the 25 Gy/5# plan and each dose level.

Conclusion

Hypofractionated dose escalation to the primary tumour up to 35 Gy/5# is technically feasible in rectal cancer radiotherapy.

Debating Pros and Cons of Total Neoadjuvant Therapy in Rectal Cancer

Simple Summary

Rectal cancers represent one third of all colorectal tumours. Patients diagnosed with localised colon cancer undergo surgery upfront, likely followed by adjuvant chemotherapy. Those diagnosed with localised rectal cancer, however, frequently benefit from neoadjuvant treatments with either radiotherapy or chemoradiotherapy before undergoing surgery. On the other hand, the benefit of adjuvant chemotherapy in this setting is more controversial. The main challenges in treating patients affected by rectal cancer encompass: decreasing the risks of local relapse and distant metastases, preserving the sphincter and minimising treatment-associated functional sequelae, and improving overall survival. Some of these fuelled the concept of total neoadjuvant therapy, namely giving all available treatments including radiotherapy and systemic chemotherapy before surgery. Here, we critically review the pros and cons of such a treatment strategy, but also discuss the biological rational to support neoadjuvant treatment intensification.

Abstract

Recently, two large, randomised phase III clinical trials of total neoadjuvant therapy (TNT) in locally advanced rectal cancer were published (RAPIDO and PRODIGE 23). These two trials compared short-course radiotherapy (SCRT) followed by chemotherapy with standard chemoradiotherapy (CRT) and chemotherapy followed by CRT with standard CRT, respectively. They showed improvement in some of the outcomes such as distant recurrence and pathological complete response (pCR). No improvement, however, was observed in local disease control or the de-escalation of surgical procedures. Although it seems lawful to integrate TNT within the treatment algorithm of localised stage II and III rectal cancer, many questions remain unanswered, including which are the optimal criteria to identify patients who are most likely to benefit from this intensive treatment. Instead of providing a sterile summary of trial results, we put these in perspective in a pros and cons manner. Moreover, we discuss some biological aspects of rectal cancer, which may provide some insights into the current decision-making process, and represent the basis for the future development of alternative, more effective treatment strategies.

Current status of total neoadjuvant therapy for locally advanced rectal cancer

Neoadjuvant chemoradiotherapy (nCRT) plus total mesorectal excision (TME) has been the standard regimen for treatment of patients with locally advanced rectal cancer (LARC), because it significantly reduces the rate of local recurrence and enables sphincter preservation. However, distant metastasis remains the major reason for treatment failure, and the value of postoperative chemotherapy is still controversial. Recent studies have examined the use of total neoadjuvant therapy (TNT), defined as induction and/or consolidation chemotherapy (CONCT) with radiotherapy (RT) or nCRT prior to surgery. The results indicated that TNT may increase the rates of chemotherapy compliance and pathological complete response (pCR), and probably improve the success rate of sphincter preservation surgery. TNT may also improve disease-free survival and overall survival, and even reduce the rate of relapse. Here, we critically appraise the existing literature on three different TNT schemes used for LARC patients.

Neoadjuvant short-course radiotherapy with consolidation chemotherapy for locally advanced rectal cancer: a systematic review and meta-analysis

BACKGROUND

Short-course radiotherapy with consolidation chemotherapy (SCRT-CCT) has emerged as a promising alternative to the long course chemoradiotherapy (LCRT) regimen in locally advanced rectal cancer management. The systematic review and meta-analysis is aimed at summarizing current evidence on SCRT-CCT and comparing it to LCRT.

MATERIAL AND METHODS

Electronic databases of MEDLINE, Web of Science, and Cochrane library were searched using a predefined search strategy returning 3314 articles. This review included 11 studies (6 randomized trials and 5 non-randomized studies) on SCRT-CCT regimen based on seven different cohorts. Weighted arithmetic means and forest plots were generated to determine summary estimates.

RESULTS

The probability of achieving pathological complete response (pCR) was higher with SCRT-CCT compared to LCRT (risk ratio [RR] = 1.75, 95% confidence interval [CI]: 1.41-2.19). No statistically significant difference in 3-year overall survival (OS) was observed between the two groups (RR= 1.06, 95% CI: 0.98-1.14). The weighted arithmetic mean of 3-year OS and pCR was 83.6% versus 80.9%, and 24.5% versus 13.6% for SCRT-CCT and LCRT, respectively. R0 resection and T-downstaging rates ranged from 69.2-100% to 47-75% for SCRT-CCT, and 71-92.3% and 41-75% for LCRT, respectively. The regimens had similar compliance, postoperative, and late toxicity, however, acute toxicity rates varied primarily due to differences in treatment protocols.

CONCLUSIONS

This review highlights the ability of SCRT-CCT to produce improved tumor response with comparable OS, R0 resection, and T-downstaging at the cost of increased acute toxicity. However, heterogeneity in treatment protocols across studies makes it difficult to provide definitive conclusions regarding the regimen. Several ongoing trials are expected to provide further evidence confirming the findings of RAPIDO trial and detail appropriate SCRT-CCT protocols to improve oncological outcomes, minimize toxicity, and determine its effectiveness as the standard-of-care for locally advanced rectal cancer patients.

Total Neoadjuvant Therapy (TNT) versus Standard Neoadjuvant Chemoradiotherapy for Locally Advanced Rectal Cancer: A Systematic Review and Meta-Analysis

BACKGROUND

Total neoadjuvant therapy (TNT) is a novel approach for locally advanced rectal cancer (LARC), which attempts to deliver both systemic chemotherapy and neoadjuvant chemoradiotherapy prior to surgery. However, its efficacy and safety remain controversial in randomized controlled trials (RCTs). We conducted this meta-analysis to assess such concerns.

MATERIALS AND METHODS

Head-to-head phase II/III RCTs were searched in Embase, PubMed, Web of Science, and the Cochrane Library, as well as other sources. The primary endpoint was pathologic complete response (pCR). Secondary endpoints were disease-free survival (DFS), overall survival (OS), local recurrence-free survival, distant metastasis-free survival, and the R0 resection rate.

RESULTS

Eight phase II/III RCTs involving 2,196 patients with LARC were assessed. The primary analysis demonstrated a statistically significant improvement in the pCR rate for TNT treatment (odds ratio, 1.77; 95% confidence interval [CI], 1.28-2.45; p = .0005). TNT treatment also showed improvements in DFS and OS outcomes compared with standard chemoradiotherapy (hazard ratio [HR], 0.83; 95% CI, 0.72-0.96; p = .03 and HR, 0.88; 95% CI, 0.74-1.05; p = .15). In addition, TNT treatment showed significant efficacy in reducing the risk of distant metastasis (HR, 0.81; 95% CI, 0.68-0.95; p = .012).

CONCLUSION

The overall pCR rate may be improved with TNT compared with standard treatment. The TNT strategy may also improve DFS and OS and reduce the risk of distant metastasis.

IMPLICATIONS FOR PRACTICE

Locally advanced rectal cancer (LARC) is a relatively common disease, with a poor prognosis because of its high metastatic potential. The role of total neoadjuvant therapy (TNT) has always been controversial. This meta-analysis found that TNT in LARC is associated with a significant improvement in overall pathologic complete response rate, disease-free survival, overall survival, and distant metastasis-free survival compared with standard treatment. TNT is a promising strategy for LARC, especially for patients who have little desire for surgery.

Development and Validation of a Nomogram and a Comprehensive Prognostic Analysis of an LncRNA-Associated Competitive Endogenous RNA Network Based on Immune-Related Genes for Locally Advanced Rectal Cancer With Neoadjuvant Therapy

Colorectal cancer (CRC) is a common digestive tract tumor worldwide. In recent years, neoadjuvant chemoradiotherapy (CRT) has been the most comprehensive treatment for locally advanced rectal cancer (LARC). In this study, we explored immune infiltration in rectal cancer (RC) and identified immune-related differentially expressed genes (IRDEGs). Then, we identified response markers in datasets in GEO databases by principal component analysis (PCA). We also utilized three GEO datasets to identify the up- and downregulated response-related genes simultaneously and then identified genes shared between the PCA markers and three GEO datasets. Based on the hub IRDEGs, we identified target mRNAs and constructed a ceRNA network. Based on the ceRNA network, we explored prognostic biomarkers to develop a prognostic model for RC through Cox regression. We utilized the specimen to validate the expression of the two biomarkers. We also utilized LASSO regression to screen hub IRDEGs and built a nomogram to predict the response of LARC patients to CRT. All of the results show that the nomogram and prognostic model offer good prognostic value and that the ceRNA network can effectively highlight the regulatory relationship. hsa-mir-107 and WDFY3-AS2 may be prognostic biomarkers for RC.

Short-course radiotherapy with consolidation chemotherapy versus conventionally fractionated long-course chemoradiotherapy for locally advanced rectal cancer: randomized clinical trial

BACKGROUND

The trial hypothesis was that, in a resource-constrained situation, short-course radiotherapy would improve treatment compliance compared with conventional chemoradiotherapy for locally advanced rectal cancer, without compromising oncological outcomes.

METHODS

In this open-label RCT, patients with cT3, cT4 or node-positive non-metastatic rectal cancer were allocated randomly to 5 × 5 Gy radiotherapy and two cycles of XELOX (arm A) or chemoradiotherapy with concurrent capecitabine (arm B), followed by total mesorectal excision in both arms. All patients received a further six cycles of adjuvant chemotherapy with the XELOX regimen. The primary endpoint was treatment compliance, defined as the ability to complete planned treatment, including neoadjuvant radiochemotherapy, surgery, and adjuvant chemotherapy to a dose of six cycles.

RESULTS

Of 162 allocated patients, 140 were eligible for analysis: 69 in arm A and 71 in arm B. Compliance with planned treatment (primary endpoint) was greater in arm A (63 versus 41 per cent; P = 0.005). The incidence of acute toxicities of neoadjuvant therapy was similar (haematological: 28 versus 32 per cent, P = 0.533; gastrointestinal: 14 versus 21 per cent, P = 0.305; grade III-IV: 2 versus 4 per cent, P = 1.000). Delays in radiotherapy were less common in arm A (9 versus 45 per cent; P < 0.001), and overall times for completion of neoadjuvant treatment were shorter (P < 0.001). The rates of R0 resection (87 versus 90 per cent; P = 0.554), sphincter preservation (32 versus 35 per cent; P = 0.708), pathological complete response (12 versus 10 per cent; P = 0.740), and overall tumour downstaging (75 versus 75 per cent; P = 0.920) were similar. Downstaging of the primary tumour (ypT) was more common in arm A (P = 0.044). There was no difference in postoperative complications between trial arms (P = 0.838).

CONCLUSION

Reduced treatment delays and a higher rate of compliance were observed with treatment for short-course radiotherapy with consolidation chemotherapy, with no difference in early oncological surgical outcomes. In time- and resource-constrained rectal cancer units in developing countries, short-course radiotherapy should be the standard of care.

Efficacy and safety of intraoperative radiotherapy in rectal cancer: A systematic review and meta-analysis

BACKGROUND

In recent years, intraoperative radiotherapy (IORT) has been increasingly used for the treatment of rectal cancer. However, the efficacy and safety of IORT for the treatment of rectal cancer are still controversial.

AIM

To evaluate the value of IORT for patients with rectal cancer.

METHODS

We searched PubMed, Embase, Cochrane Library, Web of Science databases, and conference abstracts and included randomized controlled trials and observational studies on IORT vs non-IORT for rectal cancer. Dichotomous variables were evaluated by odds ratio (OR) and 95% confidence interval (CI), hazard ratio (HR) and 95%CI was used as a summary statistic of survival outcomes. Statistical analyses were performed using Stata V.15.0 and Review Manager 5.3 software.

RESULTS

In this study, 3 randomized controlled studies and 12 observational studies were included with a total of 1460 patients, who are mainly residents of Europe, the United States, and Asia. Our results did not show significant differences in 5-year overall survival (HR = 0.80, 95%CI = 0.60-1.06; P = 0.126); 5-year disease-free survival (HR = 0.94, 95%CI = 0.73-1.22; P = 0.650); abscess (OR = 1.10, 95%CI = 0.67-1.80; P = 0.713), fistulae (OR = 0.79, 95%CI = 0.33-1.89; P = 0.600); wound complication (OR = 1.21, 95%CI = 0.62-2.36; P = 0.575); anastomotic leakage (OR = 1.09, 95%CI = 0.59-2.02; P = 0.775); and neurogenic bladder dysfunction (OR = 0.69, 95%CI = 0.31-1.55; P = 0.369). However, the meta-analysis of 5-year local control was significantly different (OR = 3.07, 95%CI = 1.66-5.66; P = 0.000).

CONCLUSION

The advantage of IORT is mainly reflected in 5-year local control, but it is not statistically significant for 5-year overall survival, 5-year disease-free survival, and complications.

Radiotherapy management of rectal cancer in the backdrop of the COVID pandemic

Background

COVID‐19 outbreak was declared as a pandemic by the World Health Organization in March 2020. Over the last 3 months, the pandemic has challenged the diagnosis and treatment of all cancer, including rectal cancer. Constraints in resources call for a change in the treatment strategy without compromising efficacy.

Recent Findings

Delivery of shorter treatment schedules for radiotherapy offers advantages like short overall treatment time, improved throughput on the machine, improved compliance and reduced risk of transmission of COVID 19. Other strategies include delaying surgery, reducing the intensity of chemotherapy and adoption of organ preservation approach.

Conclusion

The curative treatment of rectal cancer should not be hindered during the COVID pandemic, and modifications in the multi‐modality treatment will help achieve quality care.

Time interval between the completion of radiotherapy and robotic-assisted surgery among patients with stage I-III rectal cancer undergoing preoperative chemoradiotherapy

BACKGROUND

This aim of this study was to evaluate the effects of time interval between the completion of radiotherapy and robotic-assisted surgery on the outcomes among patients with rectal cancer undergoing preoperative concurrent chemoradiotherapy (CCRT).

METHODS

In total, 116 patients with stage I-III rectal cancer who underwent preoperative CCRT and robotic-assisted surgery between September 2013 and February 2019 were enrolled. Patients were categorized into two groups based on the time interval: group A (10-12 weeks) and group B (≥ 12 weeks).

RESULTS

Among the 116 enrolled patients, 98 (84.5%) had middle and lower rectal cancers. Two (1.7%) patients underwent abdominoperineal resection with a sphincter preservation rate of 98.3%. Thirty-seven (31.9%) patients had a pathologic complete response (pCR). The circumferential resection margin and distal resection margin were positive in 2 (1.7%) and 1 (0.9%) patients, respectively. Therefore, the R0 resection rate was 97.4%. A total of 24 (22.4%) patients experienced postoperative relapse and 12 (10.3%) patients died; these were slightly more common in group B than in group A (28.8% vs 15.8% and 15.3% vs 5.3%, respectively; both P > 0.05); however, this difference was nonsignificant. Three-year disease-free survival (DFS) and overall survival (OS) were 75% and 89%, respectively, among all patients. Non-significant trend of favorable 3-year DFS, 3-year OS, 3-year locoregional control rate and 3-year distant metastasis control rate were observed in group A compared with group B (all P > 0.05).

CONCLUSION

Robotic-assisted surgery after a longer interval is safe and feasible for patients with rectal cancer undergoing preoperative CCRT. The present study's results suggested that the time interval of 10-12 weeks can be considered because comparable clinical and perioperative outcomes and preferable oncological outcomes were observed for interval of this length. However, future prospective randomized clinical trials are required to verify the present finding.

Preoperative Fibrinogen-Albumin Ratio Index (FARI) is a Reliable Prognosis and Chemoradiotherapy Sensitivity Predictor in Locally Advanced Rectal Cancer Patients Undergoing Radical Surgery Following Neoadjuvant Chemoradiotherapy

Background

Inflammatory response and nutritional status are associated with cancer development and progression. The purpose of this study was to explore whether the preoperative fibrinogen-albumin ratio index (FARI) is related to prognosis and chemoradiotherapy outcome of radical surgery after neoadjuvant chemoradiotherapy (NCRT) in patients with locally advanced rectal cancer (LARC).

Methods

In total, 123 patients with LARC who underwent radical surgery after NCRT between June 2012 and December 2018 were collected in this study. Time-dependent receiver operating characteristic (ROC) curve analysis was made to evaluate the ability of the markers for forecasting prognosis. The correlation between FARI and clinicopathological parameters was analyzed. The Kaplan-Meier survival analysis, univariate and multivariate analysis based on Cox proportional hazards models, and subgroup analysis were performed to evaluate overall survival (OS) and disease-free survival (DFS). A nomogram was constructed to evaluate the predictive role of FARI in DFS.

Results

The ROC curve analysis showed that the ability of FARI on DFS prediction was superior to those of other inflammatory markers and carcinoembryonic antigen (CEA) (P<0.05). Based on the Youden's index, the optimal cut-off value of FARI was 8.8%. High FARI patients (>8.8%) showed a poor response to NCRT and a decreased DFS rate (P<0.05). In addition, multivariate analysis revealed that FARI (HR=3.098, P=0.033), neutrophil-to-lymphocyte ratio (NLR), and postoperative T stage were independent prognostic factors for DFS in TNM stage III LARC patients. However, FARI failed to distinguish patients with poor OS. Harrell's concordance index (C-index) of the nomogram containing FARI (0.807) was obviously higher than that without it (0.732) among LARC patients who underwent radical surgery after NCRT. Moreover, multivariate analysis revealed FARI (OR=3.044, P=0.012) as an independent predictor for response to NCRT.

Conclusion

Among LARC patients who underwent radical surgery after NCRT, preoperative FARI is an independent prognostic factor for DFS and an independent predictor for response to NCRT.

A mini-review of X-ray photodynamic therapy (XPDT) nonoagent constituents' safety and relevant design considerations

Conventional photodynamic therapy (PDT) has proved effective in the management of primary tumors and individual metastases. However, most cancer mortality arises from wide-spread multiple metastases. The latter has thus become the principal target in oncology, and X-ray induced photodynamic therapy (XPDT or PDTX) offers a great solution for adapting the PDT principle to deep tumors and scattered metastases. Developing agents capable of being excited by X-rays and emitting visible light to excite photosensitizers is based on challenging physical and chemical technologies, but there are fundamental biological limitations that are to be accounted for as well. In the present review, we have established eight major groups of safety determinants of NPs encompassing 22 parameters of clinical applicability of XPDT nanoparticulate formulations. Most, if not all, of these parameters can be accounted for and optimized during the design and development of novel XPDT nanoparticles.