Point: short-course radiation therapy is preferable in the neoadjuvant treatment of rectal cancer

Total neoadjuvant therapy vs standard therapy of locally advanced rectal cancer with high-risk factors for failure

BACKGROUND

For locally advanced rectal cancer (LARC), standard therapy [consisting of neoadjuvant chemoradiotherapy (CRT), surgery, and adjuvant chemotherapy (ChT)] achieves excellent local control. Unfortunately, survival is still poor due to distant metastases, which remains the leading cause of death among these patients. In recent years, the concept of total neoadjuvant treatment (TNT) has been developed, whereby all systemic ChT-mainly affecting micrometastases-is applied prior to surgery.

AIM

To compare standard therapy and total neoadjuvant therapy for LARC patients with high-risk factors for failure.

METHODS

In a retrospective study, we compared LARC patients with high-risk factors for failure who were treated with standard therapy or with TNT. High-risk for failure was defined according to the presence of at least one of the following factors: T4 stage; N2 stage; positive mesorectal fascia; extramural vascular invasion; positive lateral lymph node. TNT consisted of 12 wk of induction ChT with capecitabine and oxaliplatin or folinic acid, fluorouracil and oxaliplatin, CRT with capecitabine, and 6-8 wk of consolidation ChT with capecitabine and oxaliplatin or folinic acid, fluorouracil and oxaliplatin prior to surgery. The primary endpoint was pathological complete response (pCR). In total, 72 patients treated with standard therapy and 89 patients treated with TNT were included in the analysis.

RESULTS

Compared to standard therapy, TNT showed a higher proportion of pCR (23% vs 7%; P = 0.01), a lower neoadjuvant rectal score (median: 8.43 vs 14.98; P < 0.05), higher T-and N-downstaging (70% and 94% vs 51% and 86%), equivalent R0 resection (95% vs 93%), shorter time to stoma closure (mean: 20 vs 33 wk; P < 0.05), higher compliance during systemic ChT (completed all cycles 87% vs 76%; P < 0.05), lower proportion of acute toxicity grade ≥ 3 during ChT (3% vs 14%, P < 0.05), and equivalent acute toxicity and compliance during CRT and in the postoperative period. The pCR rate in patients treated with TNT was significantly higher in patients irradiated with intensity-modulated radiotherapy/volumetric-modulated arc radiotherapy than with 3D conformal radiotherapy (32% vs 9%; P < 0.05).

CONCLUSION

Compared to standard therapy, TNT provides better outcome for LARC patients with high-risk factors for failure, in terms of pCR and neoadjuvant rectal score.

Pathological Complete Response Following Different Neoadjuvant Treatment Strategies for Locally Advanced Rectal Cancer: A Systematic Review and Meta-analysis

Background

Pathological complete response (pCR) following neoadjuvant treatment for locally advanced rectal cancer (LARC) is associated with better survival, less local recurrence, and less distant failure. Furthermore, pCR indicates that the rectum may have been preserved. This meta-analysis gives an overview of available neoadjuvant treatment strategies for LARC and analyzes how these perform in achieving pCR as compared with the standard of care.

Methods

Pubmed, Embase, and Cochrane Central bibliographic databases were searched. Randomized controlled trials in which patients received neoadjuvant treatment for MRI-staged nonmetastatic resectable LARC were included. The primary outcome was pCR, defined as ypT0N0. A meta-analysis of studies comparing an intervention with standard fluoropyrimidine-based chemoradiation (CRT) was performed.

Results

Of the 17 articles included in the systematic review, 11 were used for the meta-analysis. Addition of oxaliplatin to fluoropyrimidine-based CRT resulted in significantly more pCR compared with fluoropyrimidine-based CRT only (OR 1.46), but at the expense of more ≥ grade 3 toxicity. Other treatment strategies, including consolidation/induction chemotherapy and short-course radiotherapy (SCRT), did not improve pCR rates. None of the included trials reported a benefit in local control or OS. Five-year DFS was significantly worse after SCRT-delay compared with CRT (59% vs. 75.1%, HR 1.93).

Conclusions

All included trials fail to deliver high-level evidence to show an improvement in pCR compared with standard fluoropyrimidine-based CRT. The addition of oxaliplatin might result in more pCR but at the expense of more toxicity. Furthermore, this benefit does not translate into less local recurrence or improved survival.

Electronic supplementary material

The online version of this article (10.1245/s10434-020-08615-2) contains supplementary material, which is available to authorized users.

Planned Short-Course Radiation (scRT) is Superior to Upfront Concurrent Chemoradiation (CCRT) in Treating Metastatic Rectal Cancer

BACKGROUND OR PURPOSE

To compare the cost-performance between planned short-course radiation and upfront concurrent chemoradiation on metastatic rectal cancer.

METHODS

A total of 75 patients with metastatic rectal cancer who underwent planned short-course radiation or upfront concurrent chemoradiation were enrolled. The Kaplan-Meier method was used to compute the survival rates. The χ² test was used to compare baseline characteristics. The Cox proportional hazards model was applied to determine the prognostic influence of clinicopathological factors.

RESULTS

The planned short-course radiation is superior to upfront concurrent chemoradiation in overall survival for the patients with metastatic rectal cancer (34.8 vs. 20.2 months, P = 0.010). The planned short-course radiation was an independent prognostic factor (P = 0.009, HR (95% CI) = 0.319(0.135-0.752)). The efficacy of radiation on downstaging was similar between planned short-course radiation and upfront concurrent chemoradiation. The total cost of concurrent chemoradiation is 4.52-fold more expensive than that of short-course radiation (340,142 vs. 75,106 NT dollars, respectively).

CONCLUSIONS

Based on the impressive cost-performance of planned short-course radiation compared with upfront concurrent chemoradiation (better OS, modest downstaging and lower cost), planned short-course radiation should be the preferred radiation approach for managing metastatic rectal cancer.

Total neoadjuvant treatment of locally advanced rectal cancer with high risk factors in Slovenia

Background In the light of a high rate of distant recurrence and poor compliance of adjuvant chemotherapy in high risk rectal cancer patients the total neoadjuvant treatment was logical approach to gaining acceptance. We aimed to evaluate toxicity and efficiency of this treatment in patients with rectal cancer and high risk factors for local or distant recurrence. Patients and methods Patients with rectal cancer stage II and III and with at least one high risk factor: T4, presence of extramural vein invasion (EMVI), positive extramesorectal lymph nodes or mesorectal fascia (MRF) involvement were treated with four cycles of induction CAPOX/FOLFOX, followed by capecitabine-based radiochemotherapy (CRT) and two consolidation cycles of CAPOX/FOLFOX before the operation. Surgery was scheduled 8-10 weeks after completition of CRT. Results From November 2016 to July 2018 66 patients were evaluable. All patients had stage III disease, 24 (36.4%) had T4 tumors, in 46 (69.7%) EMVI was present and in 47 (71.2%) MRF was involved. After induction chemotherapy, which was completed by 61 (92.4%) of patients, radiologic downstaging of T, N, stage, absence of EMVI or MRF involvement was observed in 42.4%, 62.1%, 36.4%, 69.7% and 68.2%, respectively. All patients completed radiation and 54 (81.8%) patients received both cycles of consolidation chemotherapy. Grade 3 adverse events of neoadjuvant treatment was observed in 4 (6%) patients. Five patients rejected surgery, 3 of them with radiologic complete clinical remissions. One patient did not have definitive surgery of primary tumor due to unexpected cardiac arrest few days after sigmoid colostomy formation. Among 60 operated patients pathological complete response rate was 23.3%, the rate of near complete response was 20% and in 96.7% radical resection was achieved. Pathological T, N and stage downstaging was 65%, 96.7% and 83.4%, respectively. Grade ≥ 3 perioperative complications were anastomotic leakage in 3, pelvic abscess in 1 and paralytic ileus in 2 patients. The rate of pathologic complete response (pCR) in patients irradiated with 3D conformal technique was 12.1% while with IMRT and VMAT it was 37% (p < 0.05). Hypofractionation with larger dose per fraction and simultaneous integrated boost used in the latest two was the only factor associated with pCR. ConclusionsTotal neoadjuvant treatment of high risk rectal cancer is well tolerated and highly effective with excellent tumor and node regression rate and with low toxicity rate. Longer follow up will show if this strategy will improve distant disease control and survival.

Survival benefit of statins in older patients with rectal cancer: A Swedish population-based cohort study

OBJECTIVES

Increasing evidence suggests that statins may have antitumor effects but their role in rectal cancer appears inconclusive. The aim of this study was to investigate whether statins may have an impact on survival of older and younger patients with rectal cancer.

MATERIALS AND METHODS

This study included 238 patients ≥70 years and 227 patients <70 years old, from the Southeast Health Care Region of Sweden, who were diagnosed with rectal adenocarcinoma between 2004 and 2013.

RESULTS

In the older group (n = 238), statin use at the time of diagnosis was related to better cancer-specific survival (CSS) and overall survival (OS), compared to non-use (CSS: Hazard Ratio (HR), 0.37; 95% CI, 0.19-0.72; P = .003; OS: HR, 0.62; 95% CI, 0.39-0.96; P = .032). In the older group with stages I-III disease (n = 199), statin use was associated with better disease-free survival (DFS) compared to non use (HR, 0.18; 95% CI, 0.06-0.59; P = .005). The improvement of CSS, OS and DFS remained significant after adjusting for potential confounders. In the older group with stage III disease, statin users had better CSS and DFS compared to non-users (log rank P = .043; log-rank P = .028, respectively). In the older group with short course radiotherapy, statin use was related to better CSS (log-rank P = .032). No such association was present in the younger group.

CONCLUSION

Statin use was related to improved survival in older patients with rectal cancer. This observation is important given the low cost and safety of statins as a drug.

Trends and disparities in the utilization of hypofractionated neoadjuvant radiation therapy for rectal cancer in the United States

Background

Neoadjuvant conventionally fractionated radiotherapy (CFRT) versus hypofractionated radiotherapy (HFRT) for rectal cancer (RC) is among the most controversial and debatable areas of radiotherapeutic management. This is the only known study evaluating the utilization of neoadjuvant HFRT for RC in the United States, and focuses on trends and health disparities.

Methods

The National Cancer Data Base was queried [2004-2015] for newly-diagnosed cT3-T4 N_any or cT_any N1-2 M0 rectal adenocarcinoma undergoing neoadjuvant RT, with or without chemotherapy, followed by resection. Following analysis based on temporal trends, multivariate logistic regression determined factors associated with receipt of HFRT.

Results

Altogether, 29,994 patients met study criteria: 29,724 (99%) were treated with CFRT, and 270 (1%) with HFRT. Temporally, utilization of HFRT rose significantly, from 0.2% in 2004 to 2.0% in 2015, with the steepest slope at most recent time periods. HFRT was more likely administered to older patients, those with more comorbidities, and node-positive disease (P<0.05 for all). There were racial differences, as African-Americans were independently less likely to receive HFRT (P=0.043). The two strongest predictors of HFRT administration (by odds ratio) were time period and therapy at academic centers (P<0.05 for all).

Conclusions

Although HFRT is underutilized in the US, its use is rising and has increased nearly tenfold over the last decade. Disparities in HFRT delivery are emphasized, especially concerning disease-/patient-specific factors, socioeconomic status, and race. These data may serve as a benchmark for future investigation as well as for health disparities in the radiotherapeutic treatment of RC.

Short-course Versus Long-course Neoadjuvant Therapy for Non-metastatic Rectal Cancer: Patterns of Care and Outcomes From the National Cancer Database

INTRODUCTION

The purpose of this study was to compare the utilization, pathologic response, and overall survival (OS) between long-course neoadjuvant chemoradiation (LC-CRT) and short-course neoadjuvant radiation (SC-RT) in the treatment of non-metastatic rectal cancer.

METHODS AND MATERIALS

Retrospective data was obtained from the National Cancer Database (NCDB) for patients diagnosed with clinical stage II or III (limited to T3, any N or T1-2, N1-2) rectal cancer between 2004 and 2014 (28,193 patients). Univariate and multivariate analyses were performed to investigate factors associated with receipt of SC-RT, pathologic complete response (pCR) rate, and OS. Patients were compared based on the neoadjuvant therapy they received prior to tumor resection. SC-RT was defined as 25 Gy given over 1 week prior to surgery (with or without chemotherapy as part of their treatment course). LC-CRT was defined as 45 to 60 Gy given over 5 to 6 weeks (with chemotherapy) prior to surgery.

RESULTS

A total of 27,988 (99%) of patients received LC-CRT, and 205 (1%) patients received SC-RT. Receipt of SC-RT was associated with older age, more comorbidities, and treatment at an academic facility (P < .001 for each). Additional days from radiation completion to surgery was associated with a higher pCR rate (P < .001 for both). LC-CRT did not lead to increased OS compared with SC-RT (P = .517).

CONCLUSIONS

In this United States database study, there was no improvement in OS for patients receiving LC-CRT compared with SC-RT; however, a longer interval between radiation therapy and surgery led to a higher pCR rate. Academic facilities were more likely to utilize SC-RT compared with other facilities.

Session 4: Shaping radiotherapy for rectal cancer: should this be personalized?

Preoperative radiotherapy continues to be widely used in patients with operable rectal cancer. However, the indications and goals for such treatment are evolving. Professor Marijnen reviews the historic and current evidence base for the use of preoperative neoadjuvant radiotherapy and the future challenges in tailoring the therapy according to the patients' needs and tumour stage.

Current issues of preoperative radio(chemo)therapy and its future evolution in locally advanced rectal cancer

Neoadjuvant therapies are effective for local control and tumor downstaging. Up to date, preoperative long-course chemoradiotherapy and short-course radiotherapy are the two primary guideline-recommended neoadjuvant therapies for locally advanced rectal cancer patients. However, clinicians throughout the world are trying their best to further optimize the regimens and concepts of neoadjuvants. Hence, there is an urgent need to summarize evidence regarding indications of neaoadjuvant therapies and relative merits of current standard regimens. In addition, we also reviewed the optimized regimens mainly based on short-course radiotherapy with delayed surgery, consolidation chemotherapy, induction chemotherapy, chemotherapy alone without radiation and concepts in terms of organ preservation and personalized treatments to further explore the future evolution of neoadjuvant therapies in rectal cancer.

What has preoperative radio(chemo)therapy brought to localized rectal cancer patients in terms of perioperative and long-term outcomes over the past decades? A systematic review and meta-analysis based on 41,121 patients

We asked what preoperative radiotherapy/chemoradiotherapy (PRT/PCRT) has brought to patients in terms of perioperative and long-term outcomes over the past decades. A systematic review and meta-analysis was conducted using PubMed, Embase and Web of Science databases. All original comparative studies published in English that were related to PRT/PCRT and surgical resection and which analyzed survival, postoperative and quality of life outcomes were included. Data synthesis and statistical analysis were carried out using Stata software. Data from 106 comparative studies based on 80 different trials enrolling 41,121 patients were included in our study. Based on our overall analyses, PRT/PCRT significantly improved patients' local recurrence-free survival (LRFS), but neither overall survival (OS) nor metastasis-free survival (MFS) showed improvement. In addition, PRT significantly increased the postoperative morbidity and mortality but PCRT did not have a significant effect. Furthermore, PRT/PCRT significantly increased the risk of postoperative wound complications but not anastomotic leakage and bowel obstruction. Our comprehensive subgroup analyses further supported the aforementioned results. Meanwhile, long-term anorectal symptoms (impaired squeeze pressures, use of pads, incontinence and urgency) and erectile dysfunction were also significantly increased in patients after PRT/PCRT. The benefits of PRT/PCRT as applied over the last several decades have not been sufficient to improve OS. Metastases of primary tumor and postoperative adverse effects were the two primary obstacles for an improved OS. In fact, the greatest advantage of PRT/PCRT is still local tumor control and a significantly improved LRFS.

Update on advances and controversy in rectal cancer treatment

Changes in the multidisciplinary treatment of rectal cancer have been recently proposed. We performed a comprehensive review of the current data on neoadjuvant and adjuvant treatment of rectal cancer, focussing on chemoradiotherapy treatment and timing of surgery. Six components were proposed as the framework for the treatment of rectal cancer: neoadjuvant therapy and changing patterns in patient selection, long- or short-course radiotherapy, adverse effects of radiotherapy, timing of surgery, non-operative management of rectal cancer and postoperative adjuvant therapy. Lack of a consistent difference in terms of local recurrence has been observed between short-course radiotherapy and long-course chemoradiotherapy. Indications for preoperative radiotherapy have been reconsidered in the last years. An interval of 10-11 weeks seemed to be the optimal timing, with no impact on patient safety. Since assessment criteria of clinical complete response are not well defined, and the basis for non-operative management of rectal cancer is still not clear, further investigations are required. There is controversy about standard treatments for patients with locally advanced rectal cancer that are being analyzed by ongoing studies. Tailored treatments could avoid over-treatment for a large number of patients without any impairment of the oncologic results.

Tumour regression in the randomized Stockholm III Trial of radiotherapy regimens for rectal cancer

Background

The Stockholm III Trial randomized patients with primary operable rectal cancers to either short‐course radiotherapy (RT) with immediate surgery (SRT), short‐course RT with surgery delayed 4–8 weeks (SRT‐delay) or long‐course RT with surgery delayed 4–8 weeks. This preplanned interim analysis examined the pathological outcome of delaying surgery.

Methods

Patients randomized to the SRT and SRT‐delay arms in the Stockholm III Trial between October 1998 and November 2010 were included, and data were collected in a prospective register. Additional data regarding tumour regression grade, according to Dworak, and circumferential margin were obtained by reassessment of histopathological slides.

Results

A total of 462 of 545 randomized patients had specimens available for reassessment. Patients randomized to SRT‐delay had earlier ypT categories, and a higher rate of pathological complete responses (11·8 versus 1·7 per cent; P = 0·001) and Dworak grade 4 tumour regression (10·1 versus 1·7 per cent; P < 0·001) than patients randomized to SRT without delay. Positive circumferential resection margins were uncommon (6·3 per cent) and rates did not differ between the two treatment arms.

Conclusion

Short‐course RT induces tumour downstaging if surgery is performed after an interval of 4–8 weeks.

Short‐course therapy with delay causes downstaging

Phase II trial of short-course radiotherapy followed by delayed surgery for locoregionally advanced rectal cancer

AIM

A prospective phase II study to investigate the feasibility and the rate of complete pathological response (ypT0) after short-course radiotherapy (SCRT) followed by surgery at 8 weeks.

METHOD

Operable patients with localized rectal cancer staged T3-4N0/+ or T2N+ were eligible and received 25 Gy (in one-third of patients, the gross tumor volume received a simultaneous integrated boost up to a total of 30 Gy) in five consecutive fractions to the posterior pelvis followed by surgery 8 weeks later. Pathological response and surgical toxicity were assessed in all patients.

RESULTS

Fifty-two patients (median age 68 years) completed the study. The median distance of the tumour from the anal verge was 6.5 cm. The median interval to surgery was 52 days. Three-quarters of patients underwent a low anterior resection. All underwent complete surgical resection and 100% had pathological negative margins. Ten per cent had stage ypT0 after radiotherapy. The median length of hospital stay was 8 days. Toxicity was comparable with the rates reported in the literature.

CONCLUSION

In this study, SCRT followed by delayed surgery was feasible and had acceptable toxicity. All patients underwent complete surgical resection and 100% had negative pathological margins. The rate of ypT0 was 10%.

Challenges in the neoadjuvant treatment of rectal cancer: balancing the risk of recurrence and quality of life

The management of patients with rectal cancer has improved substantially-assisted by refinements in surgical technique, the increasing accuracy of preoperative imaging, more precise delivery of radiotherapy¸and more informative feedback from the histopathologist. Multidisciplinary teams have been the key to this success. Future challenges facing multidisciplinary teams include individually tailoring therapy - in particular in deciding who does and does not need radiotherapy, utilising new radiotherapy techniques such as intensity-modulated radiotherapy and image-guided radiotherapy and new systemic therapies, and electing patients for whom chemoradiotherapy might be potentially curative without surgical resection after complete clinical response. Hence, there is an increasing focus on developing predictive and prognostic molecular biomarkers. This paper explores the background to common variations in practice, and the current and future challenges in the neoadjuvant treatment of rectal cancer.

Short-course radiotherapy followed by neo-adjuvant chemotherapy in locally advanced rectal cancer--the RAPIDO trial

BACKGROUND

Current standard for most of the locally advanced rectal cancers is preoperative chemoradiotherapy, and, variably per institution, postoperative adjuvant chemotherapy. Short-course preoperative radiation with delayed surgery has been shown to induce tumour down-staging in both randomized and observational studies. The concept of neo-adjuvant chemotherapy has been proven successful in gastric cancer, hepatic metastases from colorectal cancer and is currently tested in primary colon cancer.

METHODS AND DESIGN

Patients with rectal cancer with high risk features for local or systemic failure on magnetic resonance imaging are randomized to either a standard arm or an experimental arm. The standard arm consists of chemoradiation (1.8 Gy x 25 or 2 Gy x 25 with capecitabine) preoperatively, followed by selective postoperative adjuvant chemotherapy. Postoperative chemotherapy is optional and may be omitted by participating institutions. The experimental arm includes short-course radiotherapy (5 Gy x 5) followed by full-dose chemotherapy (capecitabine and oxaliplatin) in 6 cycles before surgery. In the experimental arm, no postoperative chemotherapy is prescribed. Surgery is performed according to TME principles in both study arms. The hypothesis is that short-course radiotherapy with neo-adjuvant chemotherapy increases disease-free and overall survival without compromising local control. Primary end-point is disease-free survival at 3 years. Secondary endpoints include overall survival, local control, toxicity profile, and treatment completion rate, rate of pathological complete response and microscopically radical resection, and quality of life.

DISCUSSION

Following the advances in rectal cancer management, increased focus on survival rather than only on local control is now justified. In an experimental arm, short-course radiotherapy is combined with full-dose chemotherapy preoperatively, an alternative that offers advantages compared to concomitant chemoradiotherapy with or without postoperative chemotherapy. In a multi-centre setting this regimen is compared to current standard with the aim of improving survival for patients with locally advanced rectal cancer.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01558921.

Intermediate-fraction neoadjuvant radiotherapy for rectal cancer

BACKGROUND

In China, standard neoadjuvant chemoradiation therapy has not been well accepted, not only because of financial constraints but also because of the poorly-tolerated long duration of the regimen.

OBJECTIVE

The current study aimed to evaluate the impact of a modified neoadjuvant radiation regimen on the prognosis of rectal cancer patients in China.

DESIGN

This was a nonrandomized cohort study evaluating outcomes of patients who chose to undergo preoperative radiotherapy compared with those who chose not to undergo preoperative radiotherapy (controls).

SETTINGS

The study was carried out in Peking University Cancer Hospital, a tertiary care cancer center in China.

PATIENTS

Records of patients with locally advanced, mid-to-low rectal cancer who underwent total mesorectal excision at Peking University Cancer Hospital from 2001 through 2005 were analyzed in this study.

INTERVENTION

Patients who chose preoperative radiotherapy received a total dose of 30 Gy delivered in 10 once-daily fractions of 3.0 Gy each, with at least a 14-day delay of surgery after delivery of the last fraction.

MAIN OUTCOME MEASURES

Tumor downstaging was evaluated. Local recurrence, distant metastases, and disease-free and overall survival were analyzed with the Kaplan-Meier method.

RESULTS

A total of 101 patients accepted and 162 patients declined the modified preoperative radiotherapy regimen. Of the 101 patients receiving preoperative radiotherapy, 5 (5%) had a complete response, and 50 (50%) achieved TNM downstaging. The local recurrence rate was 5% with preoperative radiotherapy and 18% in the control groups (p = 0.02). Within the preoperative radiotherapy group, 5-year disease-free survival and overall survival rates were significantly higher in patients with T-, N-, or TNM-downstaging than in patients without downstaging. Evaluation of literature reports indicated that clinical safety and effectiveness of the modified protocol are comparable to results of standard neoadjuvant procedures.

LIMITATIONS

The allocation to study groups was not randomized, and patient self-selection may have introduced bias, particularly because patients with greater financial means were more likely to choose to undergo the preoperative radiotherapy regimen.

CONCLUSIONS

Compared with surgery alone, this modified preoperative radiotherapy regimen is associated with significantly reduced local recurrence and complication rates, with improved survival in patients who show downstaging. The modified protocol offers a clinical outcome equivalent to standard preoperative radiotherapy regimens while offering an alternative for increasing the flexibility of preoperative radiation regimens in China.