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

Forecasting Individual Patients' Best Time for Surgery in Colon-Rectal Cancer by Tumor Regression during and after Neoadjuvant Radiochemotherapy

The standard treatment of locally advanced rectal cancer is neoadjuvant chemoradiotherapy before surgery. For those patients experiencing a complete clinical response after the treatment, a watch-and-wait strategy with close monitoring may be practicable. In this respect, the identification of biomarkers of the response to therapy is extremely important. Many mathematical models have been developed or used to describe tumor growth, such as Gompertz's Law and the Logistic Law. Here we show that the parameters of those macroscopic growth laws, obtained by fitting the tumor evolution during and immediately after therapy, are a useful tool for evaluating the best time for surgery in this type of cancer. A limited number of experimental observations of the tumor volume regression, during and after the neoadjuvant doses, permits a reliable evaluation of a specific patient response (partial or complete recovery) for a later time, and one can evaluate a modification of the scheduled treatment, following a watch-and-wait approach or an early or late surgery. Neoadjuvant chemoradiotherapy effects can be quantitatively described by applying Gompertz's Law and the Logistic Law to estimate tumor growth by monitoring patients at regular intervals. We show a quantitative difference in macroscopic parameters between partial and complete response patients, reliable for estimating the treatment effects and best time for surgery.

The Multidisciplinary Approach of Rectal Cancer: The Experience of "COMRE Group" Model

Background: Total mesorectal excision (TME) is the gold standard to treat locally advanced rectal cancer. This monocentric retrospective study evaluates the results of laparotomic, laparoscopic and robotic surgery in “COMRE GROUP” (REctalCOMmittee). Methods: 327 selected stage I-II-III patients (pts) underwent TME between November 2005 and April 2020 for low or middle rectal cancer; 91 pts underwent open, 200 laparoscopic and 36 robotic TME. Of these, we analyzed the anthropomorphic, intraoperative, anatomopathological parameters and outcome during the follow up. Results: The length of hospital stay was significantly different between robotic TME and the other two groups (8.47 ± 3.54 days robotic vs. 11.93 ± 5.71 laparotomic, p < 0.001; 8.47 ± 3.54 robotic vs. 11.10 ± 7.99 laparoscopic, p < 0.05). The mean number of harvested nodes was higher in the laparotomic group compared to the other two groups (19 ± 9 laparotomic vs. 15 ± 8 laparoscopic, p < 0.001; 19 ± 9 laparotomic vs. 15 ± 7 robotic, p < 0.05). Median follow-up was 52 months (range: 1−169). Overall survival was significantly shorter in the open TME group compared with the laparoscopic one (Chi2 = 13.36, p < 0.001). Conclusions: In the experience of the “COMRE” group, laparoscopic TME for rectal cancer is a better choice than laparotomy in a multidisciplinary context. Robotic TME has a significant difference in terms of hospital stay compared to the other two groups.

Adding Consolidation Capecitabine to Neoadjuvant Chemoradiotherapy for Locally Advanced Rectal Cancer: A Propensity-Matched Comparative Study

Aim

To determine whether adding consolidation capecitabine chemotherapy without lengthening the waiting period influences pathological complete response (pCR) and short-term outcome of locally advanced rectal cancer (LARC) receiving neoadjuvant chemoradiotherapy (NCRT).

Method

Totally, 545 LARC who received NCRT and radical resection between 2010 and 2018 were enrolled. Short-term outcome and pCR rate were compared between patients with and without additional consolidation capecitabine. Logistic analysis was performed to identify predictors of pCR.

Results

After propensity score matching, 229 patients were matched in both NCRT and NCRT-Cape groups. Postoperative morbidity was comparable between groups except for operation time, which is lower in the NCRT group (213.2 ± 67.4 vs. 227.9 ± 70.5, p = 0.025). Two groups achieved similar pCR rates (21.8 vs. 22.7%, p = 1.000). Tumor size (OR = 0.439, p < 0.001), time interval between NCRT and surgery (OR = 1.241, p = 0.003), and post-NCRT carcinoembryonic antigen (OR = 0.880, p = 0.008) were significantly correlated with pCR in patients with LARC. A predictive nomogram was constructed with a C-index of 0.787 and 0.741 on internal and external validation.

Conclusion

Adding consolidation capecitabine chemotherapy without lengthening CRT-to-surgery interval in LARC patients after NCRT does not seem to impact pCR or short-term outcome. A predictive nomogram for pCR was successful, and it could support treatment decision-making.

A Systematic Review of the Cyclooxygenase-2 (COX-2) Expression in Rectal Cancer Patients Treated with Preoperative Radiotherapy or Radiochemotherapy

The main objective of this systematic review is to investigate the expression level of the cyclooxygenase-2 (COX-2) in rectal cancer treated with either preoperative radiotherapy or radiochemotherapy. In addition, we have summarized the effects of preoperative treatment of rectal cancer with regards to the expression levels of COX-2. A systematic literature review was performed in The Cochrane Library, PubMed, Web of Science, and Scopus databases on 1 January 2021 with the usage of the following search string-(cyclooxygenase-2) OR (COX-2) AND (rectal cancer) AND (preoperative radiochemotherapy) OR (preoperative radiotherapy). Among the 176 included in the analysis, only 13 studies were included for data extraction with a total number of 2095 patients. The results of the analysis are based on the articles concerning the expression of COX-2 in rectal cancer among patients treated with preoperative radiotherapy or radiochemotherapy. A COX-2 expression is an early event involved in rectal cancer development. In cases of negative COX-2 expression, radiotherapy and radiochemotherapy might contribute to the reduction of a local recurrence. Therefore, COX-2 may be considered as a biologic factor while selecting patients for more effective, less time-consuming and less expensive preoperative treatment. However, the utility of the administration of COX-2 inhibitors to patients with COX-2 overexpression, in an attempt to improve the patients' response rate to the neoadjuvant treatment, needs an assessment in further clinical trials.

Impact of Prolonged Neoadjuvant Treatment-surgery Interval on Histopathologic and Operative Outcomes in Patients Undergoing Total Mesorectal Excision for Locally Advanced Rectal Cancer

BACKGROUND

This study primarily aimed to assess the impact of prolonged neoadjuvant treatment-surgery interval (PNSI) on histopathologic and postoperative outcomes. Impacts of the mode of neoadjuvant treatment (NT) and surgery on the outcomes were also evaluated in the same patient population.

PATIENTS AND METHODS

Between February 2011 and December 2017, patients who underwent NT and total mesorectal excision for locally advanced rectal cancer were included. PNSI was defined as >4 and >8 weeks after short-course and long-course NT modalities, respectively.

RESULTS

A total of 44 (27%) patients received short-course NT (standard interval: n=28; PNSI: n=16) and 122 (73%) patients received long-course NT (standard interval: n=39; PNSI: n=83). Postoperative morbidity was similar between the standard interval and PNSI in patients undergoing short-course [n=3 (11%) vs. n=3 (19%), P=0.455] and long-course [n=6 (15%) vs. n=16 (19%), P=0.602] NT. PNSI was associated with increased complete pathologic response in patients receiving short-course NT [0 vs. n=5 (31%), P=0.002]. Compared with short-course NT, long-course NT was superior in terms of tumor response based on the Mandard [Mandard 1 to 2: n=6 (21%) vs. 6 (38%), P=0.012] and the College of American Pathologists (CAP) [CAP 0 to 1: n=13 (46%) vs. n=8 (50%), P=0.009] scores. Postoperative morbidity was similar after open, laparoscopic, and robotic total mesorectal excision [n=1 (14.2%) vs. n=21 (21%) vs. n=6 (12.5%), P=0.455] irrespective of the interval time to surgery and the type of NT.

CONCLUSIONS

PNSI can be considered in patients undergoing short-course NT due to its potential oncological benefits. The mode of surgery performed at tertiary centers has no impact on postoperative morbidity after both NT modalities.

Delayed surgery after radio-chemotherapy for rectal adenocarcinoma is protective for anastomotic dehiscence: a single-center observational retrospective cohort study

Ideal time interval between end of neoadjuvant radio-chemotherapy (NRCT) and surgery for rectal cancer is debated. Effect that different time intervals have on postoperative complications with particular regard to anastomotic dehiscence (AD) was evaluated on 167 patients who underwent surgery after long-course NRCT. Three different time intervals were considered: (0-42; 43-56; > 57 days). A time interval > 57 days was significantly protective for AD (p = 0.04, Odds ratio = 0.35; 95% CI 0.1254-0.9585) without influence on early oncological outcomes. Optimal time interval after end of NRCT and surgery may help achieving the best pathological response with lowest postoperative morbidity.Trial registration number: Clinical Trial. Gov NCT04013347. https://clinicaltrials.gov/ct2/results?cond=&term=NCT04013347&cntry=&state=&city=&dist= ).

The Effects of Neoadjuvant Treatment on the Tumor Microenvironment in Rectal Cancer: Implications for Immune Activation and Therapy Response

BACKGROUND

Because more than one neoadjuvant treatment is available for advanced rectal cancer, the aim of this study was to compare the differential clinical and pathologic effects of different combinations of chemoradiation regimens, treatment sequencing, and timing to surgery on patient outcomes.

PATIENTS AND METHODS

Between January 2015 and October 2018, 126 newly diagnosed patients with rectal cancer with magnetic resonance imaging-based cT3-4 or N+ rectal disease for curative-intent treatment received 1 of 4 neoadjuvant regimens, followed by immediate surgery or delayed surgery. Whole post-neoadjuvant surgical specimens were assessed by 3-dimensional digital whole-tumor microarray imaging and immunostaining in pathology to analyze the global tumor pathologic regression grades, residual tumor distribution patterns, the extent of lymphovascular permeation, lymph node positivity, and the overall density of lymphocyte infiltration in the tumor microenvironment. These factors were further examined to identify possible correlations with clinical outcomes.

RESULTS

Among the 4 neoadjuvant treatment groups, including 2 conventional regimens, we found a significant increase of stromal CD3+ and CD8+ immune infiltrates in the postneoadjuvant tumor microenvironment in the 3 groups with delayed surgery after different chemoradiation regimens compared with the group with immediate surgery after a short course of RT alone. Independent of neoadjuvant chemoradiation regimens, the post-induction high-intermediate-low stromal-infiltrating CD8+ T-cell densities corresponded to tumor regression grades, distant metastasis rates, and disease-free survival and were prognostic factors for the further stratification of patients with American Joint Committee on Cancer stage III rectal cancer into different risk groups after surgery.

CONCLUSION

The effectiveness of induction strategies on tumor remission and disease recurrence in advanced rectal cancer was significantly correlated with an enhanced cytotoxic immune response in the tumor microenvironment.

Standard (8 weeks) vs long (12 weeks) timing to minimally-invasive surgery after NeoAdjuvant Chemoradiotherapy for rectal cancer: a multicenter randomized controlled parallel group trial (TiMiSNAR)

BACKGROUND

The optimal timing of surgery in relation to chemoradiation is still controversial. Retrospective analysis has demonstrated in the recent decades that the regression of adenocarcinoma can be slow and not complete until after several months. More recently, increasing pathologic Complete Response rates have been demonstrated to be correlated with longer time interval. The purpose of the trial is to demonstrate if delayed timing of surgery after neoadjuvant chemoradiotherapy actually affects pathologic Complete Response and reflects on disease-free survival and overall survival rather than standard timing.

METHODS

The trial is a multicenter, prospective, randomized controlled, unblinded, parallel-group trial comparing standard and delayed surgery after neoadjuvant chemoradiotherapy for the curative treatment of rectal cancer. Three-hundred and forty patients will be randomized on an equal basis to either robotic-assisted/standard laparoscopic rectal cancer surgery after 8 weeks or robotic-assisted/standard laparoscopic rectal cancer surgery after 12 weeks.

DISCUSSION

To date, it is well-know that pathologic Complete Response is associated with excellent prognosis and an overall survival of 90%. In the Lyon trial the rate of pCR or near pathologic Complete Response increased from 10.3 to 26% and in retrospective studies the increase rate was about 23-30%. These results may be explained on the relationship between radiation therapy and tumor regression: DNA damage occurs during irradiation, but cellular lysis occurs within the next weeks. Study results, whether confirmed that performing surgery after 12 weeks from neoadjuvant treatment is advantageous from a technical and oncological point of view, may change the current pathway of the treatment in those patient suffering from rectal cancer.

TRIAL REGISTRATION

ClinicalTrials.gov NCT3465982.

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 &lt; 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.

Feasibility of relatively low neoadjuvant radiation doses for locally advanced rectal cancer: A propensity score-matched analysis

BACKGROUND

Neoadjuvant chemoradiation therapy is part of the standard treatment of locally advanced rectal cancer (LARC). Although various options for modifying preoperative radiotherapy protocols have been researched and proposed, there is still no consensus as to the most appropriate dose regimen of neoadjuvant therapy for this disease.

AIM

To evaluate the effects of relatively low-dose radiation regimens on tumor regression and clinical outcomes in rectal cancer patients treated with neoadjuvant CRT followed by mesorectal excision.

METHODS AND RESULTS

We retrospectively analyzed patients with LARC who underwent neoadjuvant concurrent chemoradiation (CCRT) in our hospital from June 2010 to December 2015. A total of 259 consecutive patients were enrolled, receiving 42 to 44 Gy (RLD, n = 31), 46 Gy (SD1, n = 69), or 50 Gy (SD2, n = 159) of CRT, combined with either capecitabine/oxaliplatin or capecitabine only or mFOLFOX6, followed by total mesorectal excision. A 1:4 propensity score matching was employed, and all patients in the RLD group were matched with 124 patients in the SD2 group. Rates of pCR, 3-year local/regional recurrence (LRR), overall survival (OS), and disease-free survival (DFS) in the RLD group were all not significantly different (0.313 for pCR; 0.884 for LRR; and 0.762 for OS; 0.101 for DFS) from those in SD1 and SD2 groups. The RLD group showed a lower incidence of grade 3 to 4 hematologic toxicity than SD2 group (0.019). A propensity score analysis demonstrated no significant differences in the pCR rates and 3-year outcomes between the RLD and SD2 group.

CONCLUSION

Relatively low-dose regimen (≤44 Gy) of neoadjuvant CRT combined with standard concurrent chemotherapy appears to be both safe and effective in Chinese patients with LARC. Further testing by prospective randomized trials is needed.

Health-related quality of life in rectal cancer patients undergoing neoadjuvant chemoradiation with delayed surgery versus short-course radiotherapy with immediate surgery: a propensity score-matched cohort study

BACKGROUND

Neoadjuvant chemoradiation with delayed surgery (CRT-DS) and short-course radiotherapy with immediate surgery (SCRT-IS) are two commonly used treatment strategies for rectal cancer. However, the optimal treatment strategy for patients with intermediate-risk rectal cancer remains a discussion. This study compares quality of life (QOL) between SCRT-IS and CRT-DS from diagnosis until 24 months after treatment.

METHODS

In a prospective colorectal cancer cohort, rectal cancer patients with clinical stage T2-3N0-2M0 undergoing SCRT-IS or CRT-DS between 2013 and 2017 were identified. QOL was assessed using EORTC-C30 and EORTC-CR29 questionnaires before the start of neoadjuvant treatment (baseline) and at 3, 6, 12, 18 and 24 months after. Patients were 1:1 matched using propensity sore matching. Between- and within-group differences in QOL domains were analyzed with linear mixed-effects models. Symptoms and sexual interest at 12 and 24 months were compared using logistic regression models.

RESULTS

156 of 225 patients (69%) remained after matching. The CRT-DS group reported poorer emotional functioning at 3, 6, 12, 18 and 24 months (mean difference with SCRT-IS: -9.4, -12.1, -7.3, -8.0 and -7.9 respectively), and poorer global health, physical-, role-, social- and cognitive functioning at 6 months (mean difference with SCRT-IS: -9.1, -9.8, -14.0, -9.2 and -12.6, respectively). Besides emotional functioning, all QOL domains were comparable at 12, 18 and 24 months. Within-group changes showed a significant improvement of emotional functioning after baseline in the SCRT-IS group, whereas only a minor improvement was observed in the CRT-DS group. Symptoms and sexual interest in male patients at 12 and 24 months were comparable between the groups.

CONCLUSIONS

In rectal cancer patients, CRT-DS may induce a stronger decline in short-term QOL than SCRT-IS. From 12 months onwards, QOL domains, symptoms and sexual interest in male patients were comparable between the groups. However, emotional functioning remained higher after SCRT-IS than after CRT-DS.

Additional Chemotherapy with 5-FU plus Leucovorin between Preoperative Chemoradiotherapy and Surgery Improved Treatment Outcomes in Patients with Advanced Rectal Cancer

Purpose: The aim of the preliminary study was to evaluate the efficacy and safety of 4-week chemotherapy with 5-Fluorouracil and leucovorin (LV5FU2) during the resting periods between preoperative CRT and surgery in patients with LARC. Materials and Methods: Standard preoperative CRT was delivered to the entire pelvis at a total dose of 5040 Gy of radiation with concurrent 5-FU or capecitabine for 6 weeks. Twenty-three patients received additional preoperative chemotherapy with two cycles of 5-FU and LV (LV 200 mg/m2 and 5-FU bolus 400 mg/m2 on day 1, and 5-FU infusion 2400 mg/m2 for 46 hrs, every 2 weeks) after preoperative CRT. Surgery was performed at 2-4 weeks following the completion of preoperative chemotherapy. Results: Between May 2013 and January 2015, 23 patients underwent preoperative CRT, with additional chemotherapy and surgery, and 23 patients completed the scheduled treatment. The median follow-up duration was 42.0 months. The tumor down-staging rate was observed in 65.2%, and pathologic complete remission (pCR) was noted in 5 patients (21.7%). T and N down-staging were observed in 16 (69.6%) and 14 (60.9%) patients, respectively. The four-year disease-free survival (DFS) rate was 73.9% and the four-year overall survival (OS) rate was 90.9% in patients who received additional chemotherapy. The four-year DFS rate was 100% in the tumor down-staging group vs. 25.0% in the non-down staging group treated with additional chemotherapy (P <0.001). There was also a significant difference of the four-year OS rate 100% in the tumor down-staging group compared with 71.4% in the non-down staging group (P = 0.031). Conclusions: This preliminary study showed that additional preoperative chemotherapy with LV5FU2 was well tolerable and had an improvement in the downstaging rate and survival. Randomized controlled trial of this strategy is encouraged for definitive conclusions.

Clinicopathological, genomic and immunological factors in colorectal cancer prognosis

BACKGROUND

Numerous factors affect the prognosis of colorectal cancer (CRC), many of which have long been identified, such as patient demographics and the multidisciplinary team. In more recent years, molecular and immunological biomarkers have been shown to have a significant influence on patient outcomes. Whilst some of these biomarkers still require ongoing validation, if proven to be worthwhile they may change our understanding and future management of CRC. The aim of this review was to identify the key prognosticators of CRC, including new molecular and immunological biomarkers, and outline how these might fit into the whole wider context for patients.

METHODS

Relevant references were identified through keyword searches of PubMed and Embase Ovid SP databases.

RESULTS

In recent years there have been numerous studies outlining molecular markers of prognosis in CRC. In particular, the Immunoscore® has been shown to hold strong prognostic value. Other molecular biomarkers are useful in guiding treatment decisions, such as mutation testing of genes in the epidermal growth factor receptor pathway. However, epidemiological studies continue to show that patient demographics are fundamental in predicting outcomes.

CONCLUSION

Current strategies for managing CRC are strongly dependent on clinicopathological staging, although molecular testing is increasingly being implemented into routine clinical practice. As immunological biomarkers are further validated, their testing may also become routine. To obtain clinically useful information from new biomarkers, it is important to implement them into a model that includes all underlying fundamental factors, as this will enable the best possible outcomes and deliver true precision medicine.

Short-course radiotherapy with immediate or delayed surgery in rectal cancer: A meta-analysis

BACKGROUND

The safety and efficacy of preoperative short-course radiotherapy had been verified in rectal cancer. However, the timing of surgery after radiation had not been well defined. Thus, we performed this meta-analysis to compare the interval time of surgery after short-course radiotherapy in rectal cancer: immediate surgery (<4 weeks) vs delayed surgery (>4 weeks).

METHODS

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

RESULTS

In total, 5 eligible studies including 1244 participants were identified. The delayed surgery group had a markedly higher pathological complete response rate [RR = 15.71, 95% CI (2.10, 117.30), P = 0.007] and downstaging rate [RR = 2.63, 95% CI (1.77, 3.90), P < 0.00001], a higher proportion of patients with adjuvant pathologic stage 0 + I disease [RR = 1.49, 95% CI (1.23, 1.81), P < 0.0001] and a lower incidence of postoperative complications [RR = 0.81, 95% CI (0.70, 0.95), P = 0.008] than did the immediate surgery group, but the survival rate, sphincter preservation rate and R0 resection rate were similar between the two groups.

CONCLUSION

Based on better pathologic outcomes and fewer postoperative complications, we recommended short-course radiotherapy with delayed surgery for more than 4 weeks.

Tumour-infiltrating regulatory T cell density before neoadjuvant chemoradiotherapy for rectal cancer does not predict treatment response

Neoadjuvant (preoperative) chemoradiotherapy (CRT) decreases the risk of rectal cancer recurrence and reduces tumour volume prior to surgery. However, response to CRT varies considerably between individuals and factors associated with response are poorly understood. Foxp3+ regulatory T cells (Tregs) inhibit anti-tumour immunity and may limit any response to chemotherapy and radiotherapy. We have previously reported that a low density of Tregs in the tumour stroma following neoadjuvant CRT for rectal cancer is associated with improved tumour regression. Here we have examined the association between Treg density in pre-treatment diagnostic biopsy specimens and treatment response, in this same patient cohort. We aimed to determine whether pre-treatment tumour-infiltrating Treg density predicts subsequent response to neoadjuvant CRT. Foxp3+, CD8+ and CD3+ cell densities in biopsy samples from 106 patients were assessed by standard immunohistochemistry (IHC) and evaluated for their association with tumour regression grade and survival. We found no association between the density of any T cell subset pre-treatment and clinical outcome, indicating that tumour-infiltrating Treg density does not predict response to neoadjuvant CRT in rectal cancer. Taken together with the findings of the previous study, these data suggest that in the context of neoadjuvant CRT for rectal cancer, the impact of chemotherapy and/or radiotherapy on anti-tumour immunity may be more important than the state of the pre-existing local immune response.

On a prolonged interval between rectal cancer (chemo)radiotherapy and surgery

Preoperative radiotherapy (RT) or chemoradiotherapy (CRT) is often required before rectal cancer surgery to obtain low local recurrence rates or, in locally advanced tumours, to radically remove the tumour. RT/CRT in tumours responding completely can allow an organ-preserving strategy. The time from the end of the RT/CRT to surgery or to the decision not to operate has been prolonged during recent years. After a brief review of the literature, the relevance of the time interval to surgery is discussed depending upon the indication for RT/CRT. In intermediate rectal cancers, where the aim is to decrease local recurrence rates without any need for down-sizing/-staging, short-course RT with immediate surgery is appropriate. In elderly patients at risk for surgical complications, surgery could be delayed 5-8 weeks. If CRT is used, surgery should be performed when the acute radiation reaction has subsided or after 5-6 weeks. In locally advanced tumours, where CRT is indicated, the optimal delay is 6-8 weeks. In patients not tolerating CRT, short-course RT with a 6-8-week delay is an alternative. If organ preservation is a goal, a first evaluation should preferably be carried out after about 6 weeks, with planned surgery for week 8 if the response is inadequate. In case the response is good, a new evaluation should be carried out after about 12 weeks, with a decision to start a 'watch-and-wait' programme or operate. Chemotherapy in the waiting period is an interesting option, and has been the subject of recent trials with promising results.

Pre- and post-surgery treatments in rectal cancer: a long-term single-centre experience

BACKGROUND

Our study evaluated long-term survival outcomes in rectal cancer patients treated with preoperative radiotherapy, and the impact on survival of concomitant and postoperative adjuvant chemotherapy (ctx), among other prognostic factors.

METHODS

The study included 196 patients [median age: 58 years (range: 20-86 years); 63.0% men] with locally advanced rectal carcinoma and, in some cases, resectable liver metastasis. Rates of distant metastasis and local recurrence and of 5-year distant metastasis-free survival (dmfs) and overall survival (os) were determined.

RESULTS

The 5-year os rate was 57.0%, with a median duration of 81.5 months (95% confidence interval: 73.7 months to 89.4 months), and the 5-year dmfs rate was 54.1%, with a median duration of 68.4 months (95% confidence interval: 40.4 months to 96.4 months). Prognostic factors for higher os and dmfs rates were downstaging (p = 0.013 and p = 0.005 respectively), radiotherapy dose (50 Gy vs. 56 Gy or 45-46 Gy, both p = 0.002), and concomitant ctx use (p = 0.004 and p = 0.001) and type (5-fluorouracil-leucovorin-folinic acid vs. tegafur-folinic acid, p = 0.034 and p = 0.043). Adjuvant ctx after neoadjuvant long-term concomitant chemoradiotherapy (ccrt) and surgery was associated with better 5-year os rates for postoperative T0-T3 disease (p = 0.003) and disease at all lymph node stages (p = 0.001).

CONCLUSIONS

Our findings revealed a favourable survival outcome with long-term fractionated irradiation and concomitant 5-fluorouracil-based ctx, achieving 5-year os and dmfs rates of 57.0% and 54.1% respectively. Preoperative administration of radiotherapy (50 Gy) and postoperative adjuvant ctx were associated with a significant survival benefit. Radiation doses above 50 Gy and the interval between ccrt and surgery had no significant effect on survival.

Optimal fractionation of preoperative radiotherapy and timing to surgery for rectal cancer (Stockholm III): a multicentre, randomised, non-blinded, phase 3, non-inferiority trial

BACKGROUND

Radiotherapy reduces the risk of local recurrence in rectal cancer. However, the optimal radiotherapy fractionation and interval between radiotherapy and surgery is still under debate. We aimed to study recurrence in patients randomised between three different radiotherapy regimens with respect to fractionation and time to surgery.

METHODS

In this multicentre, randomised, non-blinded, phase 3, non-inferiority trial (Stockholm III), all patients with a biopsy-proven adenocarcinoma of the rectum, without signs of non-resectability or distant metastases, without severe cardiovascular comorbidity, and planned for an abdominal resection from 18 Swedish hospitals were eligible. Participants were randomly assigned with permuted blocks, stratified by participating centre, to receive either 5 × 5 Gy radiation dose with surgery within 1 week (short-course radiotherapy) or after 4-8 weeks (short-course radiotherapy with delay) or 25 × 2 Gy radiation dose with surgery after 4-8 weeks (long-course radiotherapy with delay). After a protocol amendment, randomisation could include all three treatments or just the two short-course radiotherapy treatments, per hospital preference. The primary endpoint was time to local recurrence calculated from the date of randomisation to the date of local recurrence. Comparisons between treatment groups were deemed non-inferior if the upper limit of a double-sided 90% CI for the hazard ratio (HR) did not exceed 1·7. Patients were analysed according to intention to treat for all endpoints. This study is registered with ClinicalTrials.gov, number NCT00904813.

FINDINGS

Between Oct 5, 1998, and Jan 31, 2013, 840 patients were recruited and randomised; 385 patients in the three-arm randomisation, of whom 129 patients were randomly assigned to short-course radiotherapy, 128 to short-course radiotherapy with delay, and 128 to long-course radiotherapy with delay, and 455 patients in the two-arm randomisation, of whom 228 were randomly assigned to short-course radiotherapy and 227 to short-course radiotherapy with delay. In patients with any local recurrence, median time from date of randomisation to local recurrence in the pooled short-course radiotherapy comparison was 33·4 months (range 18·2-62·2) in the short-course radiotherapy group and 19·3 months (8·5-39·5) in the short-course radiotherapy with delay group. Median time to local recurrence in the long-course radiotherapy with delay group was 33·3 months (range 17·8-114·3). Cumulative incidence of local recurrence in the whole trial was eight of 357 patients who received short-course radiotherapy, ten of 355 who received short-course radiotherapy with delay, and seven of 128 who received long-course radiotherapy (HR vs short-course radiotherapy: short-course radiotherapy with delay 1·44 [95% CI 0·41-5·11]; long-course radiotherapy with delay 2·24 [0·71-7·10]; p=0·48; both deemed non-inferior). Acute radiation-induced toxicity was recorded in one patient (<1%) of 357 after short-course radiotherapy, 23 (7%) of 355 after short-course radiotherapy with delay, and six (5%) of 128 patients after long-course radiotherapy with delay. Frequency of postoperative complications was similar between all arms when the three-arm randomisation was analysed (65 [50%] of 129 patients in the short-course radiotherapy group; 48 [38%] of 128 patients in the short-course radiotherapy with delay group; 50 [39%] of 128 patients in the long-course radiotherapy with delay group; odds ratio [OR] vs short-course radiotherapy: short-course radiotherapy with delay 0·59 [95% CI 0·36-0·97], long-course radiotherapy with delay 0·63 [0·38-1·04], p=0·075). However, in a pooled analysis of the two short-course radiotherapy regimens, the risk of postoperative complications was significantly lower after short-course radiotherapy with delay than after short-course radiotherapy (144 [53%] of 355 vs 188 [41%] of 357; OR 0·61 [95% CI 0·45-0·83] p=0·001).

INTERPRETATION

Delaying surgery after short-course radiotherapy gives similar oncological results compared with short-course radiotherapy with immediate surgery. Long-course radiotherapy with delay is similar to both short-course radiotherapy regimens, but prolongs the treatment time substantially. Although radiation-induced toxicity was seen after short-course radiotherapy with delay, postoperative complications were significantly reduced compared with short-course radiotherapy. Based on these findings, we suggest that short-course radiotherapy with delay to surgery is a useful alternative to conventional short-course radiotherapy with immediate surgery.

FUNDING

Swedish Research Council, Swedish Cancer Society, Stockholm Cancer Society, and the Regional Agreement on Medical Training and Clinical Research in Stockholm.

Delaying surgery after neoadjuvant chemoradiotherapy improves prognosis of rectal cancer

AIM

To investigate the prognostic effect of a delayed interval between neoadjuvant chemoradiotherapy (CRT) and surgery in locally advanced rectal cancer.

METHODS

We evaluated 87 patients with locally advanced mid- or distal rectal cancer undergoing total mesorectal excision following an interval period after neoadjuvant CRT at Şişli Hamidiye Etfal Training and Research Hospital, Istanbul between January 2009 and January 2014. Patients were divided into two groups according to the interval before surgery: < 8 wk (group I) and ≥ 8 wk (group II). Data related to patients, cancer characteristics and pathological examination were collected and analyzed.

RESULTS

When the distribution of timing between group I (n = 45) and group II (n = 42) was viewed, comparison of interval periods (median ± SD) of groups showed a significant difference of as 5 ± 1.28 wk in group I and 10.1 ± 2.2 wk in group II (P < 0.001). The median follow-up period for all patients was 34.5 (9.9-81) mo. group II had significantly higher rates of pathological complete response (pCR) than group I had (19% vs 8.9%, P = 0.002). Rate of tumor regression grade (TRG) poor response was 44.4% in group I and 9.5% in group II (P < 0.002). A poor pathological response was associated with worse disease-free survival (P = 0.009). The interval time did not show any association with local recurrence (P = 0.79).

CONCLUSION

Delaying the neoadjuvant CRT-surgery interval may provide nodal down-staging, improve pCR rate, and decrease the rate of TRG poor response.

Complete Pathological Response After Neoadjuvant Long-Course Chemoradiotherapy for Rectal Cancer and Its Relationship to the Degree of T3 Mesorectal Invasion

BACKGROUND

Many studies have shown significantly improved outcomes (reduced local recurrence and improved overall survival) for patients achieving a complete pathological response from neoadjuvant chemoradiotherapy.

OBJECTIVE

This study aimed to document the complete pathological response rate and outcomes in patients receiving preoperative long-course chemoradiotherapy stratified for the extent of T3 mesorectal invasion measured on preoperative imaging.

DESIGN

This is a retrospective study of prospectively collected data, of patients with rectal cancer in the Cabrini Monash University Department of Surgery colorectal neoplasia database, incorporating data from Cabrini Hospital and The Alfred Hospital, identifying patients entered between January 2010 and June 2014.

PATIENTS AND SETTINGS

One hundred eighteen patients with T3 rectal cancer met the selection criteria for the study; 26 achieved complete pathological response (22%).

MAIN OUTCOME MEASURES

Outcomes in terms of complete pathological response and oncological outcomes such as disease-free and overall survival were analyzed.

RESULTS

Patients with complete pathological response had significantly less preoperative invasion than those with no complete pathological response (p < 0.001). Depth of invasion was the only variable associated with complete pathological response (p < 0.002), and the likelihood of complete pathological response decreased by 35% for every millimeter of invasion. Complete pathological response was associated with increased disease-free survival (p = 0.018) and a lower risk of cancer progression (p = 0.046). Depth of invasion was associated with an increased risk of death after surgery; HR increased by 1.07 (95% CI, 1.00-1.15) for each 1-mm increase in invasion.

LIMITATIONS

This was a retrospective study with the usual limitations, although these were minimized through the use of a clinician-driven prospective database.

CONCLUSIONS

The smaller the degree of T3 invasion, the higher the chance of achieving complete pathological response (up to 35%), which is associated with improved disease-free and overall survival. A higher complete pathological response rate is observed in early T3 disease in comparison with more extensive T3 invasion.

Timing of surgery following neoadjuvant chemoradiotherapy in locally advanced rectal cancer - A comparison of magnetic resonance imaging at two time points and histopathological responses

PURPOSE

There is wide inter-institutional variation in the interval between neoadjuvant chemoradiotherapy (NACRT) and surgery for locally advanced rectal cancer. We aimed to assess the association of magnetic resonance imaging (MRI) at 9 and 14 weeks post-NACRT; T-staging (ymrT) and post-NACRT tumour regression grading (ymrTRG) with histopathological outcomes; histopathological T-stage (ypT) and histopathological tumour regression grading (ypTRG) in order to inform decision-making about timing of surgery.

PATIENTS AND METHODS

We prospectively studied 35 consecutive patients (26 males) with MRI-defined resection margin threatened rectal cancer who had completed standardized NACRT. Patients underwent a MRI at Weeks 9 and 14 post-NACRT, and surgery at Week 15. Two readers independently assessed MRIs for ymrT, ymrTRG and volume change. ymrT and ymrTRG were analysed against histopathological ypT and ypTRG as predictors by logistic regression modelling and receiver operating characteristic (ROC) curve analyses.

RESULTS

Thirty-five patients were recruited. Inter-observer agreement was good for all MR variables (Kappa > 0.61). Considering ypT as an outcome variable, a stronger association of favourable ymrTRG and volume change at Week 14 compared to Week 9 was found (ymrTRG - p = 0.064 vs. p = 0.010; Volume change - p = 0.062 vs. p = 0.007). Similarly, considering ypTRG as an outcome variable, a greater association of favourable ymrTRG and volume change at Week 14 compared to Week 9 was found (ymrTRG - p = 0.005 vs. p = 0.042; Volume change - p = 0.004 vs. 0.055).

CONCLUSION

Following NACRT, greater tumour down-staging and volume reduction was observed at Week 14. Timing of surgery, in relation to NACRT, merits further investigation.

TRIAL REGISTRATION NUMBER

NCT01325909.

Optimal Timing to Surgery after Neoadjuvant Chemoradiotherapy for Locally Advanced Rectal Cancer

BACKGROUND

Neoadjuvant chemoradiotherapy (nCRT) has demonstrated proven benefit in tumor regression and improved long-term local control for patients with locally advanced rectal cancer. However, precise analysis of the optimal waiting time that maximizes oncologic benefits of nCRT has not been established.

STUDY DESIGN

The 2006-2012 National Cancer Data Base was queried for patients with stage II and III rectal adenocarcinoma who underwent nCRT followed by surgical resection. Time to surgery was defined as the difference between last date of radiotherapy and date of surgery. Primary study endpoints included resection margin positivity and pathologic downstaging. Multivariable regression modeling with restricted cubic splines was used to evaluate the adjusted association between time to surgery and our study endpoints, and to establish an optimal time threshold for surgery.

RESULTS

A total of 11,760 patients were included. Median time to surgery was 53 days (interquartile range [IQR] 43 to 63 days). After adjusting for patient demographic, clinical, tumor, and treatment characteristics, our model determined an inflection point at 56 days after end of radiotherapy associated with the highest likelihood of complete resection and pathologic downstaging. With adjustment, the risk of margin positivity was increased in those who underwent surgery after 56 days from end of radiotherapy (odds ratio [OR] 1.40, 95% CI 1.21 to 1.61, p < 0.001). The likelihood of downstaging was increasing up to 56 days after radiotherapy (≥56 days vs <56 days, OR 1.2, 95% CI 1.02 to 1.23, p = 0.01).

CONCLUSIONS

This study objectively determined the optimal time for surgery after completion of nCRT for rectal cancer based on completeness of resection and tumor downstaging. Eight weeks appears to be the critical threshold for optimal tumor response.

Low stromal Foxp3+ regulatory T-cell density is associated with complete response to neoadjuvant chemoradiotherapy in rectal cancer

BACKGROUND

Foxp3+ regulatory T cells (Tregs) play a vital role in preventing autoimmunity, but also suppress antitumour immune responses. Tumour infiltration by Tregs has strong prognostic significance in colorectal cancer, and accumulating evidence suggests that chemotherapy and radiotherapy efficacy has an immune-mediated component. Whether Tregs play an inhibitory role in chemoradiotherapy (CRT) response in rectal cancer remains unknown.

METHODS

Foxp3+, CD3+, CD4+, CD8+ and IL-17+ cell density in post-CRT surgical samples from 128 patients with rectal cancer was assessed by immunohistochemistry. The relationship between T-cell subset densities and clinical outcome (tumour regression and survival) was evaluated.

RESULTS

Stromal Foxp3+ cell density was strongly associated with tumour regression grade (P=0.0006). A low stromal Foxp3+ cell density was observed in 84% of patients who had a pathologic complete response (pCR) compared with 41% of patients who did not (OR: 7.56, P=0.0005; OR: 5.27, P=0.006 after adjustment for presurgery clinical factors). Low stromal Foxp3+ cell density was also associated with improved recurrence-free survival (HR: 0.46, P=0.03), although not independent of tumour regression grade.

CONCLUSIONS

Regulatory T cells in the tumour microenvironment may inhibit response to neoadjuvant CRT and may represent a therapeutic target in rectal cancer.

Influence of internal fixation systems on radiation therapy for spinal tumor

In this study, the influence of internal fixation systems on radiation therapy for spinal tumor was investigated in order to derive a theoretical basis for adjustment of radiation dose for patients with spinal tumor and internal fixation. Based on a common method of internal fixation after resection of spinal tumor, different models of spinal internal fixation were constructed using the lumbar vertebra of fresh domestic pigs and titanium alloy as the internal fixation system. Variations in radiation dose in the vertebral body and partial spinal cord in different types of internal fixation were studied under the same radiation condition (6 MV and 600 mGy) in different fixation models and compared with those irradiated based on the treatment planning system (TPS). Our results showed that spinal internal fixation materials have great impact on the radiation dose absorbed by spinal tumors. Under the same radiation condition, the influence of anterior internal fixation material or combined anterior and posterior approach on radiation dose at the anterior border of the vertebral body was the greatest. Regardless of the kinds of internal fixation method employed, radiation dose at the anterior border of the vertebral body was significantly different from that at other positions. Notably, the influence of posterior internal fixation material on the anterior wall of the vertebral canal was the greatest. X‐ray attenuation and scattering should be taken into consideration for most patients with bone metastasis that receive fixation of metal implants. Further evaluation should then be conducted with modified TPS in order to minimize the potentially harmful effects of inappropriate radiation dose.

PACS number: 87.55.D‐

Remaining cancer cells within the fibrosis after neo-adjuvant treatment for locally advanced rectal cancer

AIM

To analyse the incidence and distribution of remaining cancer cells within the fibrosis induced by preoperative chemo-radiotherapy (CRT) for locally advanced rectal cancer.

METHODS

The histopathological specimens from 46 patients operated on with extensive surgery for locally advanced rectal cancer after CRT were examined. The extension of fibrosis in relation to the mesorectal fascia (MRF) and the distribution of cancer cells within the fibrosis was examined using routine haematoxylin-eosin staining. In addition, immunohistochemical staining with CK20 was done to examine if cancer cells were missed by routine pathological work up.

RESULTS

All specimens showed CRT induced fibrosis. Two specimens showed complete response without viable cancer cells (ypT0). The fibrosis was limited inside the MRF in three cases, adherent to or involved the MRF in ten cases and in 33 cases the fibrosis was obvious outside as well as inside the fascia. Twenty-one cases showed fibrosis on the surgical resection margin, and in 9 of these cancer cells were found on the surgical margin (R1, R2-resection). 37 patients had R0 resections and among those 24 showed fibrosis beyond the MFR and 13 had scattered cancer cells in the fibrosis along or outside the MRF.

CONCLUSIONS

The rate of remaining cancer cells within the fibrosis was high in patients with locally advanced rectal cancer treated with CRT. Frequently cancer cells were detected near the border of the fibrosis. A complete resection of the fibrosis is therefore recommended to achieve an R0 resection after neo-adjuvant treatment.

Review on adjuvant chemotherapy for rectal cancer - why do treatment guidelines differ so much?

BACKGROUND

The use of postoperative adjuvant chemotherapy is controversial for rectal adenocarcinoma. Both international and national guidelines display a great span varying from recommending no adjuvant chemotherapy at all, over single drug 5-fluororuacil (5-FU), to combinations of 5-FU/oxaliplatin.

METHODS

A review of the literature was made identifying 24 randomized controlled trials on adjuvant treatment of rectal cancer based on about 10 000 patients. The trials were subdivided into a number of clinically relevant subgroups.

RESULTS

As regards patients treated with preoperative (chemo) radiotherapy, four randomized studies were found where use of adjuvant chemotherapy showed no benefit in survival. Three trials were found in which a subset of patients received preoperative (chemo) radiotherapy. Two of these trials showed a statistically significant benefit of adjuvant chemotherapy. Twenty trials were identified in which the patients did not receive preoperative (chemo) radiotherapy, including five Asian studies in which a statistically significant benefit from adjuvant chemotherapy was reported.

CONCLUSIONS

Most of the data found did not support the use of postoperative adjuvant chemotherapy for patients already treated with preoperative (chemo) radiotherapy. For patients not treated preoperatively, several studies support the use of single agent 5-FU chemotherapy. Treatment guidelines seem to differ according to if preoperative chemoradiation is considered of importance for use of adjuvant chemotherapy and if adjuvant colon cancer studies are considered transferrable to rectal cancer patients regardless of the molecular differences.

A population-based cohort study on adherence to practice guidelines for adjuvant chemotherapy in colorectal cancer

BACKGROUND

The value of adjuvant chemotherapy in colorectal cancer is well studied, and guidelines have been established. Little is known about how treatment guidelines are implemented in the everyday clinical setting.

METHODS

This national population-based study on nearly 34,000 patients with colorectal cancer evaluates the adherence to present clinical guidelines for adjuvant chemotherapy. Virtually all patients with colorectal cancer in Sweden during the years 2007-2012 and data from the Swedish Colorectal Cancer Registry were included.

RESULTS

In colon cancer stage III, adherence to national guidelines was associated with lower age, presence of multidisciplinary team (MDT) conference, low co-morbidity, and worse N stage. The MDT forum also affected whether or not high-risk stage II colon cancer patients were considered for adjuvant chemotherapy. Rectal cancer patients both in stage II and III were considered for adjuvant chemotherapy less often than colon cancer patients, but the same factors influenced the decision. Adjuvant chemotherapy was started later than eight weeks after surgery in 30% of colon cancer patients and in 38% of rectal cancer patients.

CONCLUSIONS

In Sweden, the adherence to national guidelines for adjuvant chemotherapy in colon cancer stage III is acceptable in younger and healthier patients. MDT conferences are of major importance and affect whether patients are recommended for adjuvant chemotherapy. Special consideration needs to be given to certain subgroups of patients, particularly older patients and patients with poorly differentiated tumors. There is a need to shorten the waiting time until start of chemotherapy.