Impact of the interval between short-course radiotherapy and surgery on outcomes of rectal cancer patients

Single pre-operative radiation therapy (SPORT-CK) trial for low-risk breast cancer: Early results of a phase 2 study

BACKGROUND AND PURPOSE

Preoperative partial breast irradiation (PBI) is a novel technique that can be used in patients with early-stage breast cancer with the goal of limiting the irradiated breast volume, toxicity and number of fractions. The aim of this trial is to assess the toxicity, surgical, oncologic and cosmetic outcomes of preoperative PBI.

MATERIALS AND METHODS

In this single-arm phase II trial, we enrolled women ≥ 60 years, with unifocal low-risk breast invasive ductal carcinoma (cT1N0, grade 1-2, ER+, Her2-). Patients were treated with a single fraction of 20 Gy of preoperative PBI using volumetric modulated arc therapy (VMAT). Patients then underwent breast-conserving surgery (BCS) +/- sentinel lymph node biopsy within 72 h of radiation. Primary outcomes were rate of surgical complications and early toxicity. Secondary outcomes were cosmesis at 12 months, chronic toxicity and ipsilateral breast tumor recurrence.

RESULTS

Twenty-five patients were recruited with a median age of 67 years, and a median follow-up of 60 months. Sentinel biopsy was positive in 1 out of 24 patients (4 %). Two patients received adjuvant RT for close margins or positive lymph nodes. Within the first 90 days, none of the patients had surgical complications; almost all had grade 0 to 1 acute and late RTOG skin toxicity. The cosmetic outcome was rated between good and excellent in all cases by physicians and patients, except for one patient who self-rated her cosmesis as fair as of the third year. There were no recurrences.

CONCLUSION

Preoperative single-fraction PBI is a safe and feasible treatment for elderly patients with low-risk early-stage breast cancer, with no surgical complications, very low rates of acute and late radiation toxicity, and excellent cosmetic outcomes. Randomized controlled trials are needed to compare preoperative to adjuvant PBI in this patient population.

What is the optimal timing of surgery after short-course radiotherapy for rectal cancer?

BACKGROUND

Short-course neoadjuvant radiotherapy is a valuable tool in managing rectal cancers and has improved local recurrence rates. However, limited and conflicting data has resulted in variable usage and a lack of consensus on the optimal timing of surgery following short-course radiotherapy. This review aims to provide a contemporary summation of the available evidence regarding the optimal time interval between short-course neoadjuvant radiotherapy and surgery.

METHODS

A focused literature search was undertaken using the PubMed and Embase databases from January 1980 until January 2023. Randomised control trials, large observational studies and systematic reviews focusing on the use of short-course preoperative radiotherapy for localised rectal cancers, with a focus on the timing of surgery, were included. Primary outcomes were overall survival, disease-free survival and perioperative complications.

RESULTS

Five randomised control trials, two meta-analyses, and two large, population-based studies were included for their eligibility and relevance. Increased downstaging and fewer postoperative complications are demonstrated in patients receiving delayed surgery (> four weeks), but more recent data raise concerns regarding increased rates of local recurrence in this cohort. Studies directly comparing different time intervals to surgery following short-course radiotherapy have failed to demonstrate an effect on overall survival.

CONCLUSIONS

This review highlights the complexities and relative shortcomings of the available data with few high-quality studies and randomised control trials directly comparing different time intervals to surgery following short-course radiotherapy. Continuing research is needed to confirm existing findings and explore gaps in the current literature.

Timing of rectal cancer surgery after short-course radiotherapy: national database study

BACKGROUND

Previous randomized trials found that a prolonged interval between short-course radiotherapy (SCRT, 25 Gy in 5 fractions) and surgery for rectal cancer (4-8 weeks, SCRT-delay) results in a lower postoperative complication rate and a higher pCR rate than SCRT and surgery within a week (SCRT-direct surgery). This study sought to confirm these results in a Dutch national database.

METHODS

Patients with intermediate-risk rectal cancer (T3(mesorectal fascia (MRF)-) N0 M0 and T1-3(MRF-) N1 M0) treated with either SCRT-delay (4-12 weeks) or SCRT-direct surgery in 2018-2021 were selected from a Dutch national colorectal cancer database. Confounders were adjusted for using inverse probability of treatment weighting (IPTW). The primary endpoint was the 90-day postoperative complication rate. Secondary endpoints included the pCR rate. Endpoints were compared using log-binomial and Poisson regression.

RESULTS

Some 664 patients were included in the SCRT-direct surgery and 238 in the SCRT-delay group. After IPTW, the 90-day postoperative complication rate was comparable after SCRT-direct surgery and SCRT-delay (40.1 versus 42.3 per cent; risk ratio (RR) 1.1, 95 per cent c.i. 0.9 to 1.3). A pCR occurred more often after SCRT-delay than SCRT-direct surgery (10.7 versus 0.4 per cent; RR 39, 11 to 139).

CONCLUSION

There was no difference in surgical complication rates between SCRT-delay and SCRT-direct, but SCRT-delay was associated with more patients having a pCR.

Neoadjuvant Therapy for Locally Advanced Rectal Cancer: Recent Advances and Ongoing Challenges

Locally advanced rectal cancer has a rising global incidence. Over the last 4 decades, advances first in surgery and later in radiotherapy and chemoradiotherapy have improved outcomes, particularly with regard to local recurrence. Unfortunately, distant metastases remain a significant problem. In clinical trials of patients with stage II and III disease, distant relapse occurs in 25% to 30% of patients regardless of the treatment approach. Recent phase 3 trials have therefore focused on intensification of systemic therapy for localized disease, with an aim of reducing the distant relapse rate. Early results of trials of total neoadjuvant therapy with combination systemic therapy provided in the neoadjuvant setting are promising; for the first time, a significant improvement in the rate of distant relapse has been noted. Longer-term follow-up is eagerly awaited. On the other hand, trimodal therapy with chemotherapy, radiotherapy, and surgery is toxic. Several trials are currently assessing the feasibility of a watch-and-wait approach, omitting surgery in those with complete response to neoadjuvant treatment, in an attempt to reduce the burden of treatment on patients. The future for rectal cancer patients is likely to be highly personalized, with more intense approaches for high-risk patients and omission of unnecessary therapy for those whose disease responds well to initial treatment. Biomarkers such as circulating tumor DNA will help to more accurately stratify patients into risk groups. Improvements in survival and quality of life are expected as the results of ongoing research become available throughout the next decade.

Radiation Therapy for Rectal Cancer: Executive Summary of an ASTRO Clinical Practice Guideline

PURPOSE

This guideline reviews the evidence and provides recommendations for the indications and appropriate technique and dose of neoadjuvant radiation therapy (RT) in the treatment of localized rectal cancer.

METHODS

The American Society for Radiation Oncology convened a task force to address 4 key questions focused on the use of RT in preoperative management of operable rectal cancer. These questions included the indications for neoadjuvant RT, identification of appropriate neoadjuvant regimens, indications for consideration of a nonoperative or local excision approach after chemoradiation, and appropriate treatment volumes and techniques. Recommendations were based on a systematic literature review and created using a predefined consensus-building methodology and system for grading evidence quality and recommendation strength.

RESULTS

Neoadjuvant RT is recommended for patients with stage II-III rectal cancer, with either conventional fractionation with concurrent 5-FU or capecitabine or short-course RT. RT should be performed preoperatively rather than postoperatively. Omission of preoperative RT is conditionally recommended in selected patients with lower risk of locoregional recurrence. Addition of chemotherapy before or after chemoradiation or after short-course RT is conditionally recommended. Nonoperative management is conditionally recommended if a clinical complete response is achieved after neoadjuvant treatment in selected patients. Inclusion of the rectum and mesorectal, presacral, internal iliac, and obturator nodes in the clinical treatment volume is recommended. In addition, inclusion of external iliac nodes is conditionally recommended in patients with tumors invading an anterior organ or structure, and inclusion of inguinal and external iliac nodes is conditionally recommended in patients with tumors involving the anal canal.

CONCLUSIONS

Based on currently published data, the American Society for Radiation Oncology task force has proposed evidence-based recommendations regarding the use of RT for rectal cancer. Future studies will look to further personalize treatment recommendations to optimize treatment outcomes and quality of life.

The optimal timing for the interval to surgery after short course preoperative radiotherapy (5 ×5 Gy) in rectal cancer - are we too eager for surgery?

BACKGROUND

The improved overall survival (OS) after short course preoperative radiotherapy (SCPRT) using 5 × 5 Gy reported in the early rectal cancer trials could not be replicated in subsequent phase III trials. This original survival advantage is attributed to poor quality of surgery and the large differential in local recurrence rates, with and without SCPRT. Immuno-modulation during and after SCPRT and its clinical implications have been poorly investigated. We propose an alternative explanation for this survival benefit in terms of immunological mechanisms induced by SCPRT and the timing of surgery, which may validate the concept of consolidation chemotherapy.

MATERIAL AND METHODS

We reviewed randomized controlled trials (RCTs) and studies of SCPRT from 1985 to 2019. We aimed to examine the precise timing of surgery in days following SCPRT and identify evidence for immune modulation, neo-antigens and memory cell induction by radiation.

RESULTS

Considerable variability is reported in randomised trials for median overall treatment time (OTT) from start of SCPRT to surgery (8-14 days). Only three early trials showed a benefit in terms of OS from SCPRT, although the level of benefit in preventing local recurrence was consistent across all trials. Different patterns of immune effects are observed within days after SCPRT depending on the OTT, but human leukocyte antigen (HLA)-1 expression was not upregulated.

CONCLUSIONS

SCPRT has a substantial immune-stimulatory potential. The importance of the timing of surgery after SCPRT may have been underestimated. An optimal interval for surgery after 5 × 5 Gy may lead to better outcomes, which is possibly exploited in total neoadjuvant therapy schedules using consolidation chemotherapy. Individual patient meta-analyses from appropriate SCPRT trials examining outcomes for each day and prospective trials are needed to clarify the validity of this hypothesis. The interaction of SCPRT with tumour adaptive immunology, in particular the kinetics and timing, should be examined further.

Time to Surgery Following Short-Course Radiotherapy in Rectal Cancer and its Impact on Postoperative Outcomes. A Population-Based Study Across the English National Health Service, 2009-2014

AIMS

Preoperative short-course radiotherapy (SCRT) is an important treatment option for rectal cancer. The length of time between completing SCRT and surgery may influence postoperative outcomes, but the evidence available to determine the optimal interval is limited and often conflicting.

MATERIALS AND METHODS

Information was extracted from a colorectal cancer data repository (CORECT-R) on all surgically treated rectal cancer patients who received SCRT in the English National Health Service between April 2009 and December 2014. The time from radiotherapy to surgery was described across the population. Thirty-day postoperative mortality, returns to theatre, length of stay and 1-year survival were investigated in relation to the interval between radiotherapy and surgery.

RESULTS

Within the cohort of 3469 patients, the time to surgery was 0-7 days for 76% of patients, 8-14 days for 19% of patients and 15-27 days for 5% of patients. There was a clear variation in relation to different patient characteristics. There was, however, no evidence of differences in postoperative outcomes in relation to interval length.

CONCLUSIONS

This study suggests that the time interval between SCRT and surgery does not influence postoperative outcomes up to a year after surgery. The study provides population-level, real-world evidence to complement that from clinical trials.

Postoperative complications in relation to overall treatment time in patients with rectal cancer receiving neoadjuvant radiotherapy

Background

The optimal timing of surgery for rectal cancer after radiotherapy (RT) is disputed. The Stockholm III trial concluded that it was oncologically safe to delay surgery for 4–8 weeks after short-course RT (SRT), with fewer postoperative complications compared with SRT with surgery within a week. Other studies have indicated that an even shorter interval between RT and surgery (0–3 days) might be beneficial. The aim of this study was to identify the optimal interval to surgery after RT.

Methods

Patients were analysed as treated, in terms of overall treatment time (OTT), the interval from the start of RT until the day of surgery. Patients receiving SRT (5 × 5 Gy) were categorized according to OTT: 7 days (group A), 8–13 days (group B), 5–7 weeks (group C) and 8–13 weeks (group D). Patients receiving long-course RT (25 × 2 Gy) were grouped into those with an OTT of 9–11 weeks (group E) or 12–14 weeks (group F). Outcomes assessed were postoperative complications and early mortality.

Results

A total of 810 patients were analysed (group A, 100; group B, 247; group C, 192; group D, 160; group E, 52; group F, 59). Baseline patient characteristics were similar. There were significantly more overall complications in group B than in groups C and D. Adjusted odds ratios, with B as the reference group, were: 0·72 (95 per cent c.i. 0·40 to 1·32; P = 0·289), 0·50 (0·30 to 0·84; P = 0·009) and 0·39 (0·23 to 0·65; P < 0·001) for groups A, C and D respectively. Early mortality was similar in all groups. There were no significant differences between long-course RT groups.

Conclusion

These results suggest that surgery should optimally be delayed for 4–12 weeks (OTT 5–13 weeks) after SRT.

The Impact of Surgical Timing on Pathologic Tumor Response after Short Course and Long Course Preoperative Chemoradiation for Locally Advanced Rectal Adenocarcinoma

Purpose

A pooled analysis of multi-institutional trials was performed to analyze the effect of surgical timing on tumor response by comparing short course concurrent chemoradiotherapy (CCRT) with long course CCRT followed by delayed surgery in locally advanced rectal cancer.

Materials and Methods

Three hundred patients with cT3-4N0-2 rectal adenocarcinoma were included. Long course patients from KROG 14-12 (n=150) were matched 1:1 to 150 short course patients from KROG 10-01 (NCT01129700) and KROG 11-02 (NCT01431599) according to stage, age, and other risk factors. The primary endpoint was to determine the interval between surgery and the last day of neoadjuvant CCRT which yields the best tumor response after the short course and long course CCRT. Downstaging was defined as ypT0-2N0M0 and pathologic complete response (ypCR) was defined as ypT0N0M0, respectively.

Results

Both the long and short course groups achieved lowest downstaging rates at < 6 weeks (long 20% vs. short 8%) and highest downstaging rates at 6-7 weeks (long 44% vs. short 40%). The ypCR rates were lowest at < 6 weeks (both long and short 0%) and highest at 6-7 weeks (long 21% vs. short 11%) in both the short and long course arms. The downstaging and ypCR rates of long course group gradually declined after the peak at 6-7 weeks and those of the short course group trend to constantly increase afterwards.

Conclusion

It is optimal to perform surgery at least 6 weeks after both the short course and long course CCRT to obtain maximal tumor regression in locally advanced rectal adenocarcinoma.

Gender-related prognostic significance of clinical and biological tumor features in rectal cancer patients receiving short-course preoperative radiotherapy

AIM

To study the prognostic value of clinical and biological features of rectal cancer and potential gender differences in patients' overall survival (OS), local recurrence-free survival (RFS) and metastasis-free survival (MFS) after short-course preoperative radiotherapy (SCRT) with short or long interval between RT and surgery (break).

BACKGROUND

The length of the interval between RT and surgery in SCRT is debatable and gender-related differences in patients survival are not established yet.

MATERIALS AND METHODS

126 patients received SCRT with 5 Gy dose per fraction during 5 days, followed by radical surgery after short break ≤17 days, and a long break >17 days. Pretreatment tumor proliferation (bromodeoxyuridine labeling index, BrdUrdLI and S-phase fraction) was evaluated by flow cytometry and proteins: CD34, Ki-67, GLUT-1, Ku70, BCL-2, P53 expression was studied immunohistochemically.

RESULTS

The studied group included 84 men and 42 women. There were 33, 76, and 17 cTNM (AJCC) tumor stages I, II, III, respectively. The median follow-up time was 53.3 months (range 2-142 months). For the whole group Cox multivariate analysis revealed that tumor grade (G > 1), interval between RT and surgery >17 days, pTNM stage >1 and P53 positivity + BrdUrdLI > 7.9% were negative prognostic factors for OS. Tumor aneuploidy and MVD > 140.8 vessels/mm² were important for RFS. pTNM stage > 1 and P53 positivity combined with BrdUrdLI > 7.9% were risk predictors for MFS. Based on tumor biological features, gender-related difference in OS, RFS, and MFS were observed. In multivariate analysis, male patients age > 62 years and break >17 days only appeared to be significant for OS.

CONCLUSIONS

In male rectal patients treated with SCRT, breaks between RT and surgery >17 days should be avoided because they negatively influence patients' survival.

Effect of adding mFOLFOX6 after neoadjuvant chemoradiation in locally advanced rectal cancer: a multicentre, phase 2 trial

BACKGROUND

Patients with locally advanced rectal cancer who achieve a pathological complete response to neoadjuvant chemoradiation have an improved prognosis. The need for surgery in these patients has been questioned, but the proportion of patients achieving a pathological complete response is small. We aimed to assess whether adding cycles of mFOLFOX6 between chemoradiation and surgery increased the proportion of patients achieving a pathological complete response.

METHODS

We did a phase 2, non-randomised trial consisting of four sequential study groups of patients with stage II-III locally advanced rectal cancer at 17 institutions in the USA and Canada. All patients received chemoradiation (fluorouracil 225 mg/m(2) per day by continuous infusion throughout radiotherapy, and 45·0 Gy in 25 fractions, 5 days per week for 5 weeks, followed by a minimum boost of 5·4 Gy). Patients in group 1 had total mesorectal excision 6-8 weeks after chemoradiation. Patients in groups 2-4 received two, four, or six cycles of mFOLFOX6, respectively, between chemoradiation and total mesorectal excision. Each cycle of mFOLFOX6 consisted of racemic leucovorin 200 mg/m(2) or 400 mg/m(2), according to the discretion of the treating investigator, oxaliplatin 85 mg/m(2) in a 2-h infusion, bolus fluorouracil 400 mg/m(2) on day 1, and a 46-h infusion of fluorouracil 2400 mg/m(2). The primary endpoint was the proportion of patients who achieved a pathological complete response, analysed by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00335816.

FINDINGS

Between March 24, 2004, and Nov 16, 2012, 292 patients were registered, 259 of whom (60 in group 1, 67 in group 2, 67 in group 3, and 65 in group 4) met criteria for analysis. 11 (18%, 95% CI 10-30) of 60 patients in group 1, 17 (25%, 16-37) of 67 in group 2, 20 (30%, 19-42) of 67 in group 3, and 25 (38%, 27-51) of 65 in group 4 achieved a pathological complete response (p=0·0036). Study group was independently associated with pathological complete response (group 4 compared with group 1 odds ratio 3·49, 95% CI 1·39-8·75; p=0·011). In group 2, two (3%) of 67 patients had grade 3 adverse events associated with the neoadjuvant administration of mFOLFOX6 and one (1%) had a grade 4 adverse event; in group 3, 12 (18%) of 67 patients had grade 3 adverse events; in group 4, 18 (28%) of 65 patients had grade 3 adverse events and five (8%) had grade 4 adverse events. The most common grade 3 or higher adverse events associated with the neoadjuvant administration of mFOLFOX6 across groups 2-4 were neutropenia (five in group 3 and six in group 4) and lymphopenia (three in group 3 and four in group 4). Across all study groups, 25 grade 3 or worse surgery-related complications occurred (ten in group 1, five in group 2, three in group 3, and seven in group 4); the most common were pelvic abscesses (seven patients) and anastomotic leaks (seven patients).

INTERPRETATION

Delivery of mFOLFOX6 after chemoradiation and before total mesorectal excision has the potential to increase the proportion of patients eligible for less invasive treatment strategies; this strategy is being tested in phase 3 clinical trials.

FUNDING

National Institutes of Health National Cancer Institute.

Could preoperative short-course radiotherapy be the treatment of choice for localized advanced rectal carcinoma?

Short-course preoperative radiotherapy (RT) is widely used in northern Europe for locally advanced resectable rectal cancer, but its role in the era of advanced imaging techniques is uncertain. Here, we reviewed articles and abstracts on SCRT published from 1974 through 2013 with the goal of identifying patients who might be best suited for short-course RT. We included relevant articles comparing surgery with or without preoperative radiation published before and after the advent of total mesorectal excision. We also analyzed two randomized trials directly comparing short-course RT with conventionally fractionated chemoradiation (the Polish Colorectal Study Group and the Trans-Tasman Radiation Oncology Group) that compared short-course RT with conventional chemoradiotherapy. We conclude from our review that short-course RT can be generally applied for operable rectal cancer and produces high rates of pelvic control with acceptable toxicity; it reduces local recurrence rates but does not increase overall survival. SCRT seems to be best used for tumors considered "low risk," i.e., those that are >5 cm from the anal margin, without circumferential margin involvement, and involvement of fewer than 4 lymph nodes. Whether sequential chemotherapy can further improve outcomes remains to be seen, as does the best time for surgery (immediately or 6-8 weeks after RT). We further recommend that selection of patients for short-course RT should be based on findings from magnetic resonance imaging or transrectal ultrasonography.

Optimal Time Intervals between Pre-Operative Radiotherapy or Chemoradiotherapy and Surgery in Rectal Cancer?

BACKGROUND

In rectal cancer therapy, radiotherapy or chemoradiotherapy (RT/CRT) is extensively used pre-operatively to (i) decrease local recurrence risks, (ii) allow radical surgery in non-resectable tumors, and (iii) increase the chances of sphincter-saving surgery or (iv) organ-preservation. There is a growing interest among clinicians and scientists to prolong the interval from the RT/CRT to surgery to achieve maximal tumor regression and to diminish complications during surgery.

METHODS

The pros and cons of delaying surgery depending upon the aim of the pre-operative RT/CRT are critically evaluated.

RESULTS

Depending upon the clinical situation, the need for a time interval prior to surgery to allow tumor regression varies. In the first and most common situation (i), no regression is needed and any delay beyond what is needed for the acute radiation reaction in surrounding tissues to wash out can potentially only be deleterious. After short-course RT (5Gyx5) with immediate surgery, the ideal time between the last radiation fraction is 2-5 days, since a slightly longer interval appears to increase surgical complications. A delay beyond 4 weeks appears safe; it results in tumor regression including pathologic complete responses, but is not yet fully evaluated concerning oncologic outcome. Surgical complications do not appear to be influenced by the CRT-surgery interval within reasonable limits (about 4-12 weeks), but this has not been sufficiently explored. Maximum tumor regression may not be seen in rectal adenocarcinomas until after several months; thus, a longer than usual delay may be of benefit in well responding tumors if limited or no surgery is planned, as in (iii) or (iv), otherwise not.

CONCLUSION

A longer time interval after CRT is undoubtedly of benefit in some clinical situations but may be counterproductive in most situations. After short-course RT, long-term results from the clinical trials are not yet available to routinely recommend an interval longer than 2-5 days, unless the tumor is non-resectable at diagnosis.

Neoadjuvant radiotherapy (5 × 5 Gy): immediate versus delayed surgery

GOALS

To evaluate the role of length of the interval between 5 × 5 Gy and surgery.

METHODS

PubMed was searched to perform a systematic review.

RESULTS

There were 10 studies on 5 × 5 Gy with delayed surgery (no of patients (n) = 1343), and six studies on 5 × 5 Gy with consolidation chemotherapy delivered over a long interval prior to surgery in a tight sequence (n = 244). In total, there were four randomized studies, five phase II studies, and seven retrospective studies. Trials that compared immediate with delayed surgery after 5 × 5 Gy showed a benefit in terms of lower rate of severe acute post-radiation toxicity (4.2 % absolute difference) in the immediate-surgery group. However, this benefit was counterbalanced by the increase in minor postoperative complications (13 % of absolute difference) in the group with immediate surgery compared with that with the delayed surgery. The pathological complete response (pCR) rate was about 10 % higher in the delayed-surgery group. There were no differences in sphincter preservation and R0 resection rate between the two groups. Small studies suggest no differences in the oncological outcomes. Regarding elderly patients who were unfit for chemotherapy, short-course radiotherapy with delayed surgery produced favourable outcomes for "unresectable" cancer or for small cancer after full-thickness local excision. A watch-and-wait policy in complete responders after short-course radiotherapy is feasible. A pCR of over 20 % was recorded after short-course radiotherapy and consolidation chemotherapy compared with about 10 % after 5 × 5 Gy and delayed surgery. Favourable outcomes after short-course radiotherapy and consolidation chemotherapy were observed in patients with potentially resectable stage IV disease.

CONCLUSIONS

Evidence showed that 5 × 5 Gy with delayed surgery can be used routinely for the management of elderly patients who are unfit for chemotherapy in case of "unresectable" cancer or early cancer prior to local excision. Short-course radiotherapy with consolidation chemotherapy is a promising treatment that can be used routinely for potentially resectable stage IV disease.