Sequential short-course radiation therapy and chemotherapy in the neoadjuvant treatment of rectal adenocarcinoma

Short-term outcomes of short- and long-course chemoradiotherapy before total mesorectal excision for locally advanced rectal tumors: A single-center study in Taiwan utilizing propensity score matching

BACKGROUND

Locally advanced rectal tumors are typically treated with neoadjuvant chemoradiotherapy. Short-course chemoradiotherapy (SCRT, 2500 cGy in five fractions) is a convenient alternative to concurrent chemoradiotherapy with long-course radiotherapy (CCRT, 4500 cGy in 25 fractions) without sacrificing efficacy. We aimed to compare the short-term outcomes of SCRT and CCRT in patients with mid- and low- rectal tumors who underwent total mesorectal excision using real-world data.

METHODS

We retrospectively reviewed the data of patients with locally advanced rectal cancer who underwent radical resection after neoadjuvant chemoradiotherapy from 2011 to 2022. We analyzed the clinicopathological findings and prognostic factors for disease-free and overall survival in the SCRT and CCRT groups and compared the outcomes using propensity score matching.

RESULTS

Among the 66 patients in the two groups, no disparities were noted in the demographic features, pathological remission, or downstaging rates. Nonetheless, the SCRT group exhibited superior 3-year disease-free survival (81.8% vs 62.1%, p = 0.011), whereas the overall survival did not differ significantly between the two groups. The initial carcinoembryonic antigen (CEA) levels and neoadjuvant SCRT were associated with the recurrence rates [hazard ratio (HR) = 1.13-4.10; HR = 0.19-0.74], but the harvested lymph node count was not (HR = 0.51-1.97).

CONCLUSION

Among patients with locally advanced rectal cancer, SCRT combined with four cycles of FOLFOX was shown to enhance short-term disease-free survival. Factors impacting recurrence include the initial CEA level and SCRT, but not the harvested lymph node count.

Surgical and local control outcomes after sequential short-course radiation therapy and chemotherapy for rectal cancer

Background

Total neoadjuvant therapy (TNT) is an accepted approach for the management of locally advanced rectal cancer (LARC) and is associated with a decreased risk of development of metastatic disease compared to standard neoadjuvant therapy. However, questions remain regarding surgical outcomes and local control in patients who proceed to surgery, particularly when radiation is given first in the neoadjuvant sequence. We report on our institution's experience with patients who underwent short-course radiation therapy, consolidation chemotherapy, and surgery.

Methods

We retrospectively reviewed surgical specimen outcomes, postoperative complications, and local/pelvic control in a large cohort of patients with LARC who underwent neoadjuvant therapy incorporating upfront short-course radiation therapy followed by consolidation chemotherapy.

Results

In our cohort of 83 patients who proceeded to surgery, a complete/near-complete mesorectal specimen was achieved in 90 % of patients. This outcome was not associated with the time interval from completion of radiation to surgery. Postoperative complications were acceptably low. Local control at two years was 93.4 % for all patients- 97.6 % for those with low-risk disease and 90.4 % for high-risk disease.

Conclusion

Upfront short-course radiation therapy and consolidation chemotherapy is an effective treatment course. Extended interval from completion of short-course radiation therapy did not impact surgical specimen quality.

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.

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.

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.

The concept and use of the neoadjuvant rectal score as a composite endpoint in rectal cancer

There is no universally accepted instrument to use as a validated surrogate endpoint for overall survival in phase 2 and phase 3 multimodal rectal cancer trials using chemoradiotherapy. Efforts are hampered by the inaccuracy of clinical TNM staging, the variability of indications for neoadjuvant treatment, and diverse definitions of tumour regression grade. Pathological complete response is commonly used, but fails to capture information from the majority of patients. The neoadjuvant rectal score categorises response and downstaging from the entire trial population to identify whether or not a novel treatment group in a chemoradiation trial is superior by predicting overall survival outcomes. Additionally, the neoadjuvant rectal score assesses the difference between initial clinical and pathological T stage and the presence or absence of nodal involvement after treatment. The neoadjuvant rectal score has been conceptually, but incompletely, statistically validated by two independent trial datasets. However, a fundamental weakness of the score is that no preoperative phase 3 trials in locally advanced rectal cancer in the past 20 years have provided a significant benefit in overall survival to statistically validate the neoadjuvant rectal score as a surrogate endpoint for overall survival. We review the robustness, practical value, applicability, generalisability, advantages, and disadvantages of the neoadjuvant rectal score as a surrogate endpoint for overall survival and recommend how this score could be improved and be acceptable as a standard endpoint in studies investigating neoadjuvant chemotherapy and chemoradiation in patients with rectal cancer.

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.

Organ Preservation in Rectal Cancer

A proportion of patients with rectal cancer who undergo neoadjuvant treatment end up with a complete pathological response. Because these patients have excellent oncological outcomes, many have questioned if surgical treatment in this population constitutes overtreatment. There is growing interest in watch and wait with selective organ preservation for rectal cancer patients. We review the fundamentals and key considerations of this approach including patient selection, available treatment regimens, assessment of response, long-term monitoring of response, and long-term oncological and functional outcomes.

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.

Management of Locally Advanced Rectal Cancer During The COVID-19 Pandemic: A Necessary Paradigm Change at Memorial Sloan Kettering Cancer Center

The COVID-19 pandemic will consume significant health care resources. Given the concerns for rapidly increasing infection rates in the United States, impending staffing shortages, and the potential for resource reallocation, we rapidly reevaluated our rectal cancer practice policies during this public health emergency. Before the pandemic, we commonly used total neoadjuvant therapy with a strong preference for long-course chemoradiation. In the setting of the ongoing pandemic, we now mandate short-course radiation therapy (SCRT). Despite multiple randomized trials demonstrating no difference in locoregional recurrence, distant recurrence, or overall survival between SCRT and long-course chemoradiation, the adaptation of SCRT in the United States has been low given concerns for less tumor downstaging and increased toxicity. In the setting of the ongoing and likely prolonged COVID-19 pandemic, we feel that these concerns must be reevaluated, because SCRT presents a well-validated alternative that will allow us to meet the needs of a greater number of potentially curable patients at a time when resources are severely and acutely constrained.