Preoperative chemoradiation with irinotecan and capecitabine in patients with locally advanced resectable rectal cancer: long-term results of a Phase II study

Combination of irinotecan silicasome nanoparticles with radiation therapy sensitizes immunotherapy by modulating the activation of the cGAS/STING pathway for colorectal cancer

Our previous clinical trial (Identifier: NCT02605265) revealed that addition of irinotecan (IRIN) to neoadjuvant chemoradiotherapy for rectal cancer could improve the curative effect. However, the adverse effects caused by IRIN limited the wide application of IRIN chemoradiotherapy. This study aimed to explore the mechanism under the synergistic effects of IRIN plus radiation therapy in colorectal cancer (CRC) cells and optimization of IRIN delivery via a silicasome nanocarrier in vivo. Our results revealed that compared with single IRIN or radiation treatment, IRIN combined with radiation therapy remarkably activated the intracellular cGAS/STING pathway, and promoted the expression levels of major histocompatibility complex class I (MHC-I) and programmed death ligand 1 (PD-L1). Further, a silicasome (mesoporous silica nanoparticle coated with lipid bilayer) nanocarrier was utilized to improve the delivery of IRIN with enhanced efficacy and reduced side effects. In the MC38 CRC syngeneic tumor model, IRIN silicasome combined with radiation therapy demonstrated a greater antitumor efficacy than free IRIN plus radiation therapy. Flow cytometry showed the increased number of CD4+ T cells, CD8+ T cells, and dendritic cells (DCs) in tumor in the IRIN silicasome plus radiation group. The immunofluorescence staining further confirmed the activated immune microenvironment with the elevated interferon-γ (IFN-γ) deposition. Besides, the antitumor effect of IRIN silicasome plus radiation therapy was synergistically enhanced by anti-PD-1 immunotherapy. These findings indicated that the combination of IRIN silicasome with radiation therapy could sensitize immunotherapy by manipulating the cGAS/STING pathway serving as a new strategy for CRC treatment.

Radiosensitizing Effects of Irinotecan versus Oxaliplatin Alone and in Combination with 5-Fluorouracil on Human Colorectal Cancer Cells

To date, oxaliplatin and irinotecan are used in combination with 5-flourouracil (5-FU) for metastatic colorectal cancer. In this study it was tested whether oxaliplatin and irinotecan and their combinations with 5-FU have an enhanced effect when treated simultaneously with ionizing radiation. In addition, it should be compared whether one combination therapy is more effective than the other. Colorectal cancer cells (HT-29) were treated with irinotecan or oxaliplatin, both alone and in combination with 5-FU, and subsequently irradiated. The cell growth, metabolic activity and proliferation of cells were investigated, and the clonogenic survival was determined. Furthermore, the assessment of radiation-induced DNA damage and the influence of the drugs and their combinations on DNA damage repair was investigated. Treatment with irinotecan or oxaliplatin in combination with 5-FU inhibited proliferation and metabolic activity as well as clonogenic survival and the DNA damage repair capacity of the tumor cells. The comparison of oxaliplatin and irinotecan with simultaneous irradiation showed the same effect of both drugs. When oxaliplatin or irinotecan was combined with 5-FU, tumor cell survival was significantly lower than with monotherapy; however, there was no superiority of either combination regimen. Our results have shown that the combination of 5-FU and irinotecan is as effective as the combination of 5-FU with oxaliplatin. Therefore, our data support the use of FOLFIRI as a radiosensitizer.

Patient-derived tumor organoids predict responses to irinotecan-based neoadjuvant chemoradiotherapy in patients with locally advanced rectal cancer

Adding irinotecan to neoadjuvant chemoradiotherapy (nCRT) in locally advanced rectal cancer (LARC) increases the pathologic complete response (pCR) rate but brings more toxicities. Robust biomarkers to predict response to irinotecan-based nCRT are extremely necessary for selecting the right patients. Our previous study suggests that patient-derived tumor organoids (PDTOs) sensitivity to chemoradiotherapy matches patient responses. In this study, we investigated whether PDTOs sensitivity to irinotecan can predict complete response (CR) and survival. Eligible patients receiving irinotecan-based nCRT between April 5, 2017 and December 11, 2020 were enrolled in the training cohort (n = 91) for response prediction and survival analysis. Patients receiving nCRT between February 21, 2021 and September 17, 2021 were included in the validation cohort (n = 27). Predictive performances of irinotecan organoid size ratio (OSR) for CR or pCR were evaluated. The irinotecan-sensitive groups had higher response rates compared with the insensitive groups (training cohort: 71.8% vs 24.4%, P < .0001; validation cohort, 81.8% vs 18.8%, P = .002). Moreover, the irinotecan-sensitive group had higher rates of 3-year disease-free survival (DFS: 71.6% vs 55.5%, P = .034) and distant metastasis-free survival (DMFS, 77.9% vs 57.2%, P = .015) than the irinotecan-insensitive group. 5-FU and irradiation sensitivities failed to predict 3-year DFS (5-FU: 65.4% vs 61.9%, P = .643; irradiation: 84.8% vs 57.8%; P = .072). Performances of irinotecan OSR to predict CR or pCR were good in the training cohort (CR: AUC = 0.828; 95% CI = 0.723-0.932; pCR: AUC = 0.864; 95% CI = 0.759-0.961). The validation showed robust predictive ability (CR: AUC = 0.796, 95% CI = 0.5974-0.9952; pCR: AUC = 0.917, 95% CI = 0.7921-1.0000). Irinotecan sensitivity in PDTOs was a predictive and prognostic factor in LARC.

Preoperative versus postoperative chemoradiotherapy for locally advanced rectal cancer: Outcomes of survival, toxicity, sphincter preserving and prognostic factors

BACKGROUND

This study aimed to compare preoperative chemoradiotherapy (CRT) with postoperative CRT regarding survival, local control, disease control, sphincter preservation, toxicity and also prognostic factors for the treatment of locally advanced rectal cancer.

METHODS

Records of 140 patients with locally advanced rectal cancer who received preoperative or postoperative CRT were analyzed retrospectively. We compared the treatment groups (preoperative vs postoperative) according to baseline characteristics (demographic and rectal cancer disease characteristics), and also carried out the survival analyses.

RESULTS

From January 2010 to December 2019, 140 patients were included in the analysis, 65 received preoperative treatment and 75 postoperative treatment. There was no difference in survival, recurrence or distant metastasis rate in both treatment groups. The ratios of the failure to complete adjuvant chemotherapy (32% vs 4.6%) and acute grade 3-4 toxicity (32% vs 6.2%) were higher in the postoperative group (p < 0.001). In lower located tumors (≤5 cm from anal verge) the ratio of the sphincter preserving in the preoperative group was 60.7% (n = 17/28), and was 16.6% (n = 3/18) in the postoperative group (Yates χ2 = 5.829, p = 0.005).

CONCLUSION

This study showed no difference in recurrence and survival rate. Preoperative CRT is the preferred treatment for patients with locally advanced rectal cancer, given that it is associated with a superior overall treatment compliance rate, reduced toxicity, and an increased rate of sphincter preservation in low-lying tumors, but not for overall survival.

Organoids as a Robust Preclinical Model for Precision Medicine in Colorectal Cancer: A Systematic Review

BACKGROUND

Patients with locally advanced or metastatic colorectal cancer (CRC) display heterogeneous responses to standard-of-care therapy. Robust preclinical models of malignancy in the form of patient-derived tumor organoids (PDTOs) have recently come to the fore in tailoring patient care to a personalized medicine level. This study aimed to review the literature systematically regarding PTDOs and gauge their impact on precision medicine in the management of CRC.

METHODS

A PRISMA-compliant systematic review of the MEDLINE, EMBASE, Web of Science, and Cochrane Library databases was performed. The results were categorized based on the primary objective of the individual studies as follows: organoid use in predicting effective hyperthermic intraperitoneal chemotherapy (HIPEC), systemic chemotherapy in CRC, or neoadjuvant chemoradiotherapy in rectal cancer.

RESULTS

The literature search found 200 publications, 16 of which met the inclusion criteria. Organoid models of primary and metastatic CRC have been increasingly used to assess clinical responses to standard therapy. Marked heterogeneity exists, matching the responses observed in clinical practice with ex vivo drug and radiation screening. Repeated correlation between organoid and patient sensitivity to forms of HIPEC, systemic chemotherapy, and chemoradiotherapy has been observed.

CONCLUSION

Patient-derived tumor organoids are the latest tool in predictive translational research. Current organoid-based studies in precision medicine have shown their great potential for predicting the clinical response of patients to CRC therapy. Larger-scale, prospective data are required to fully support this exciting avenue in cancer care.

Recent advances in (chemo-)radiation therapy for rectal cancer: a comprehensive review

The role of radiation therapy in the treatment of (colo)-rectal cancer has changed dramatically over the past decades. Introduced with the aim of reducing the high rates of local recurrences after conventional surgery, major developments in imaging, surgical technique, systemic therapy and radiation delivery have now created a much more complex environment leading to a more personalized approach. Functional aspects including reduction of acute or late treatment-related side effects, sphincter or even organ-preservation and the unsolved problem of still high distant failure rates have become more important while local recurrence rates can be kept low in the vast majority of patients. This review summarizes the actual role of radiation therapy in different subgroups of patients with rectal cancer, including the current standard approach in different subgroups as well as recent developments focusing on neoadjuvant treatment intensification and/or non-operative treatment approaches aiming at organ-preservation.

Multicenter, Randomized, Phase III Trial of Neoadjuvant Chemoradiation With Capecitabine and Irinotecan Guided by UGT1A1 Status in Patients With Locally Advanced Rectal Cancer

Differentiating the irinotecan dose on the basis of the uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) genotype improves the pathologic complete response (pCR) rate. In this study, we further investigated preoperative irinotecan combined with capecitabine-based chemoradiotherapy for locally advanced rectal cancer.

Impact of preoperative chemoradiotherapy using concurrent S-1 and CPT-11 on long-term clinical outcomes in locally advanced rectal cancer

BACKGROUND

Preoperative chemoradiotherapy regimens using a second drug for locally advanced rectal cancer are still under clinical investigation.

AIM

To investigate the clinical outcomes of patients with locally advanced rectal cancer treated with preoperative chemoradiotherapy using tegafur/gimeracil/oteracil (S-1) plus irinotecan (CPT-11).

METHODS

This was a single-center retrospective study of 82 patients who underwent radical surgery for rectal cancer after chemoradiotherapy with S-1 (80 mg/m²/d), CPT-11 (60 mg/m²/d), and radiation (total 45 Gy) between 2009 and 2016. The median follow-up was 51 mo (range: 17–116 mo).

RESULTS

Twenty-nine patients (35.4%) had T3 or T4 rectal cancer with mesorectal fascia invasion, 36 (43.9%) had extramural vascular invasion, 24 (29.8%) had N2 rectal cancer and eight (9.8%) had lateral lymph node swelling. The relative dose intensity was 90.1% for S-1 and 92.9% for CPT-11. Seventy-nine patients (96.3%) underwent R0 resection. With regard to pathological response, 13 patients (15.9%) had a pathological complete response and 52 (63.4%) a good response (tumor regression grade 2/3). The 5-year local recurrence-free survival, relapse-free survival and overall survival rates were 90.1%, 72.5% and 91.3%, respectively. We analyzed the risk factors for local recurrence-free survival by Cox regression analysis and none were detected. Previously described risk factors such as T4 stage, mesorectal fascia invasion or lateral lymph node swelling were not detected as negative factors for local recurrence-free survival.

CONCLUSION

We demonstrated good compliance and favorable tumor regression in patients with locally advanced rectal cancer treated with preoperative S-1 and CPT-11.

The Impact of Chemotherapy Completion on the Efficacy of Irinotecan in the Preoperative Chemoradiotherapy of Locally Advanced Rectal Cancer: An Expanded Analysis of the CinClare Phase III Trial

BACKGROUND

This study explored the impact of chemotherapy completion on irinotecan efficacy in preoperative chemoradiotherapy in patients with locally advanced rectal cancer.

PATIENTS AND METHODS

Patients with locally advanced rectal cancer (T3/4 and/or LN+) receiving neoadjuvant chemoradiotherapy were enrolled. All received preoperative pelvic radiotherapy concurrently with capecitabine and irinotecan, followed by a course of XELIRI and surgery. Patients were divided into low- and high-completion groups based on their cycles of concurrent irinotecan (1-3 or 4-5). Tumor response was compared. Significant risk factors for low completion were investigated by logistic regression modeling then a predictive nomogram was built.

RESULTS

Overall, 371 patients were enrolled, with 102 patients from CinClare phase III trial (NCT02605265). Proportions of patients with low and high completion were 38.8% and 61.2%, respectively. In the general population, the complete tumor response rates (combining sustained clinical complete response and pathologic complete response) were 21.5% and 33.6% in the low- and high-completion groups, respectively (P = .02), which were 24.2% versus 43.5% in the CinClare group (P = .08). The pathologic complete response rates were 19.4% and 26.1%, respectively (P = .19). A predictive nomogram was established and 3 different risk groups (low, intermediate, and high risk) were identified, with high completion rates of 29.2%, 50.0%, and 68.9%, respectively (P < .0001).

CONCLUSION

Our analysis suggested higher completion of concurrent irinotecan was associated with better tumor response for patients with locally advanced rectal cancer with UGT1A1∗1∗1 or UGT1A1∗1∗28 phenotypes in the neoadjuvant setting, and at least 4 cycles was recommended.

An expansion study of genotype-driven weekly irinotecan and capecitabine in combination with neoadjuvant radiotherapy for locally advanced rectal cancer with UGT1A1 *1*1 genotype

BACKGROUND

In our previous dose-escalation study, we uncovered the maximum tolerated dose (MTD) of weekly irinotecan was escalated to 80 mg/m2 and 65 mg/m2 for UDP glucuronosyltransferase family 1 member A1 (UGT1A1) *1*1 and *1*28 rectal cancer patients in neoadjuvant chemoradiotherapy (nCRT). This is an expansion study for *1*1 patients.

METHODS

Patients with clinical stage T3-4, N0-2 rectal cancer eligible for preoperative chemoradiotherapy were screened for the UGT1A1*28 genotype. A total of 52 patients with the *1*1 genotype were enrolled. Whole-pelvic intensity-modulated radiation therapy was given in 50 Gy/25 fractions. Concurrently, irinotecan of 80 mg/m2 and capecitabine of 625 mg/m2 twice daily from Monday to Friday were administered weekly. Primary endpoint was toxicities; secondary endpoints included pathological complete response (pCR), tumour-regression grading, treatment compliance, overall survival, local recurrence and disease-free survival.

RESULTS

All patients completed capecitabine-based radiotherapy as scheduled, and 42 (81%) patients completed more than three cycles of weekly irinotecan. Overall, grade 3/4 toxicities were observed in 20 cases, including 11 leucopenia, 10 neutropenia and 12 diarrhoea. Forty-three patients (83%) underwent a radical surgery, and 12 were evaluated as pCR. Another four patients accepted a watch-and-wait strategy because of clinical complete response (CCR).

CONCLUSIONS

Our data demonstrated manageable toxicities and an encouraging CCR rate for UGT1A1 *1*1 genotype in an enhanced neoadjuvant therapy. A phase III trial is ongoing to evaluate the value of irinotecan in neoadjuvant therapy (CinClare) [ClinicalTrials.gov identifier: NCT02605265].

Phase I study of preoperative chemoradiotherapy with sequential oxaliplatin and irinotecan with S-1 for locally advanced rectal cancer

The present study designed a novel preoperative chemoradiotherapy (CRT) with sequential oxaliplatin and irinotecan with S-1 for locally advanced rectal cancer (LARC). This phase I study evaluated the maximum tolerated dose and recommended dose (RD) of oxaliplatin following irinotecan with S-1. Patients with clinical stage T3 or 4 or involvement of the regional nodes and no evidence of distant metastases were treated with fixed doses of S-1 (80 mg/m²/day) on days 1-5, 8-12, 15-19, 22-27 and 29-33, and irinotecan (40 mg/m²/day) on days 1 and 8, followed by oxaliplatin on days 22 and 29. The dose of oxaliplatin was initially 40 mg/m² (level 1) with a predefined dose escalation schedule. The radiation dose was 1.8 Gy/fraction to a total dose of 45 Gy. A total of 9 patients were enrolled in the present study and 7 patients completely received CRT with this study protocol. The maximum tolerated dose for oxaliplatin was 50 mg/m² (level 2). Three of four patients experienced dose-limiting toxicity (grade 3 diarrhea) in oxaliplatin phase of level 2 dose. The RD of oxaliplatin was 40 mg/m² (level 1 dose). In addition, 2 patients had pathological CR (28.5%). Novel preoperative CRT with sequential oxaliplatin and irinotecan with S-1 for LARC resulted in acceptable toxicity and promising efficacy. However, the RD of oxaliplatin was lower than in previous CRT studies that combined oxaliplatin with S-1. To administer higher oxaliplatin, we have planned a phase I trial of preoperative CRT with sequential oxaliplatin followed by irinotecan with S-1 for LARC.

UGT1A1 polymorphisms in rectal cancer associated with the efficacy and toxicity of preoperative chemoradiotherapy using irinotecan

The purpose of the present study was to assess the efficacy and toxicity of preoperative chemoradiotherapy using irinotecan against locally advanced lower rectal cancer according to UDP-glucuronosyltransferase 1A1 (UGT1A1) polymorphisms. Between 2009 and 2016, 46 patients with resectable rectal cancer (T3-T4, N0-N2, M0) received preoperative chemoradiotherapy consisting of 80 mg/m2 per day tegafur/gimeracil/oteracil (S-1; days 1-5, 8-12, 22-26, and 29-33), 60 mg/m2 per day irinotecan (days 1, 8, 22, and 29), and 45 Gy radiation (1.8 Gy/day, 5 days per week for 5 weeks). Six to eight weeks after completing chemoradiotherapy, total mesorectal excision was carried out. Patients with UGT1A1 polymorphisms were divided into WT (n = 26), heterozygous (n = 15), and homozygous (n = 5) groups, the latter including double heterozygosities. We evaluated associations between clinical characteristics, including UGT1A1 polymorphisms, and chemoradiotherapy efficacy and toxicity. Incidence rates of grade 3+ neutropenia and diarrhea were 17.0% and 30.4%, respectively. Relative dose intensity was 89.3%. Pathological complete response rate (grade 3) was 26.1%, and the good response (grade 2/3) rate was 84.8%. UGT1A1 polymorphisms were significantly associated with neutropenia and pathological good responses, but not with diarrhea. UGT1A1 polymorphism was the only predictive factor for pathological good responses. Our results indicate that UGT1A1 polymorphism is a predictive factor to determine the clinical efficacy of preoperative chemoradiotherapy and hematological toxicity induced by chemoradiotherapy using irinotecan in locally advanced rectal cancer patients.

Tumor-Infiltrating Lymphocyte Function Predicts Response to Neoadjuvant Chemoradiotherapy in Locally Advanced Rectal Cancer

Purpose

The presence of tumor-infiltrating lymphocytes (TILs) in tumors is superior to conventional pathologic staging in predicting patient outcome. However, their presence does not define TIL functionality. Here we developed an assay that tests TIL cytotoxicity in patients with locally advanced rectal cancer before definitive treatment, identifying those who will obtain a pathologic complete response (pCR). We also used the assay to demonstrate the rescue of TIL function after checkpoint inhibition blockade (CIB).

Patients and Methods

Thirty-four consecutive patients were identified initially, with successful completion of the assay before surgery in those 17 patients who underwent full treatment. An in vitro cytotoxic assay of rectal cancer tumoroids cocultured with patient-matched TILs was established and validated. Newly diagnosed patients were recruited with pretreatment biopsy specimens processed within 1 month. Evaluation of TIL-mediated tumoroid lysis was performed by measuring the mean fluorescence intensity of cell death marker, propidium iodide. CIB (anti–programmed cell death protein 1 [anti–PD-1] antibody) response was also assessed in a subset of patient specimens.

Results

Six of the 17 patients achieved an objective pCR on final evaluation of the resected specimen after neoadjuvant chemoradiotherapy. Cytotoxic killing identified the pCR group with a higher mean fluorescence intensity (27,982 [95% CI, 25,340 to 30,625]) compared with the non-pCR cohort (12,428 [95% CI, 9,434 to 15,423]; p < .001). Assessment of the effectiveness of CIB revealed partial restoration of cytotoxicity in TILs with increased PD-1 expression with anti–PD-1 antibody exposure.

Conclusion

Evaluating TIL function can be undertaken within weeks of the diagnostic biopsy, affording the potential to alter patient management decisions and refine selection for a watch-and-wait protocol. This cytotoxic assay also has the potential to serve as a platform to assist in the additional development of CIB.

Systematic review of treatment intensification using novel agents for chemoradiotherapy in rectal cancer

BACKGROUND

With the well established shift to neoadjuvant treatment for locally advanced rectal cancer, there is increasing focus on the use of radiosensitizers to improve the efficacy and tolerability of radiotherapy. There currently exist few randomized data exploring novel radiosensitizers to improve response and it is unclear what the clinical endpoints of such trials should be.

METHODS

A qualitative systematic review was performed according to the PRISMA guidelines using preset search criteria across the PubMed, Cochrane and Scopus databases from 1990 to 2017. Additional results were generated from the reference lists of included papers.

RESULTS

A total of 123 papers were identified, of which 37 were included; a further 60 articles were obtained from additional referencing to give a total of 97 articles. Neoadjuvant radiosensitization for locally advanced rectal cancer using fluoropyrimidine-based chemotherapy remains the standard of treatment. The oral derivative capecitabine has practical advantages over 5-fluorouracil, with equal efficacy, but the addition of a second chemotherapeutic agent has yet to show a consistent significant efficacy benefit in randomized clinical assessment. Preclinical and early-phase trials are progressing with promising novel agents, such as small molecular inhibitors and nanoparticles.

CONCLUSION

Despite extensive research and promising preclinical studies, a definite further agent in addition to fluoropyrimidines that consistently improves response rate has yet to be found.

Prognostic value of tumour regression grade in locally advanced rectal cancer: a systematic review and meta-analysis

AIM

The current standard of care for locally advanced rectal cancer involves neoadjuvant chemoradiotherapy (CRT) followed by total mesorectal excision. There is a spectrum of response to neoadjuvant therapy; however, the prognostic value of tumour regression grade (TRG) in predicting disease-free survival (DFS) or overall survival (OS) is inconsistent in the literature.

METHOD

This study was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A systematic search was undertaken using Ovid MEDLINE, Embase and Google Scholar. Inclusion criteria were Stage II and III locally advanced rectal cancer treated with long-course CRT followed by radical surgery. The aim of the meta-analysis was to assess the prognostic implication of each TRG for rectal cancer following neoadjuvant CRT. Long-term prognosis was assessed. The main outcome measures were DFS and OS. A random effects model was performed to pool the hazard ratio (HR) from all included studies.

RESULTS

There were 4875 patients from 17 studies, with 775 (15.9%) attaining a pathological complete response (pCR) and 719 (29.9%) with no response. A significant association with OS was identified from a pooled-estimated HR for pCR (HR = 0.47, P = 0.002) and nonresponding tumours (HR = 2.97; P < 0.001). Previously known tumour characteristics, such as ypN, lymphovascular invasion and perineural invasion, were also significantly associated with DFS and OS, with estimated pooled HRs of 2.2, 1.4 and 2.3, respectively.

CONCLUSION

In conclusion, the degree of TRG was of prognostic value in predicting long-term outcomes. The current challenge is the development of a high-validity tests to predict pCR.

A review of preoperative chemoradiotherapy for lower rectal cancer

In Western countries, rectal cancer has been treated by chemoradiotherapy (CRT) for several decades now, and good local control has been reported. However, Japanese guidelines did not strongly recommend CRT, because CRT is only useful for achieving local control and imbues no survival benefit. For this reason, CRT was rarely used to treat rectal cancer in Japan. However, in the 2000s, several studies involving CRT began to be reported from Western countries, such as “correlation between pathological complete response and survival,” “induction chemotherapy followed by CRT,” and “watch-and-wait policies.” These studies were directly correlated with survival of and benefits to the patients. Given these findings, Japanese institutions have recently begun to introduce CRT for rectal cancer. Therefore, in the present study, we reviewed several topics regarding CRT for rectal cancer.

A Randomized Phase 2 Trial of Consolidation Chemotherapy After Preoperative Chemoradiation Therapy Versus Chemoradiation Therapy Alone for Locally Advanced Rectal Cancer: KCSG CO 14-03

PURPOSE

Preoperative chemoradiation therapy (CRT) followed by total mesorectal excision (TME) in locally advanced rectal cancer is the standard of care. To date, the role of consolidation chemotherapy after CRT has rarely been addressed through randomized trials. This study aimed to evaluate the efficacy of CRT followed by consolidation chemotherapy compared with CRT alone.

METHODS AND MATERIALS

This study enrolled patients with adenocarcinoma of the rectum and cT3 or cT4 disease with any N category and no metastasis. In arm A (control arm), we planned CRT (50.4 Gy in 28 fractions) with capecitabine followed by TME. In arm B, 2 cycles of capecitabine and oxaliplatin were administered 1 week after the completion of CRT before TME (capecitabine, 1700 mg/m² per day from day 1 to 14, and oxaliplatin, 100 mg/m² on day 1, every 3 weeks). The downstaging rate (the proportion of ypT0 to ypT2 and ypN0M0) was the primary endpoint, which was to be tested with a 1-sided type I error of 15% and with 85% power.

RESULTS

From September 2014 to February 2016, 110 patients (56 in arm A and 54 in arm B) were randomized and 108 (55 in arm A and 53 in arm B) started CRT. TME was conducted per protocol in 96 patients (52 in arm A and 44 in arm B). In arms A and B, downstaging was achieved in 21.2% and 36.4% (P = .077), respectively, and the pathologic complete response rate was 5.8% and 13.6% (P = .167), respectively. Grade ≥3 adverse events occurred in 3.6% of patients in arm A and 9.4% of patients in arm B during the preoperative treatment phase and in 1.9% and 9.0%, respectively, during the postoperative recovery phase.

CONCLUSIONS

Consolidation chemotherapy with 2 cycles of capecitabine and oxaliplatin demonstrated a marginal improvement in the downstaging rate. However, a phase 3 trial of this strategy is discouraged because of the high dropout rate and safety issues.

Phase 2 Neoadjuvant Treatment Intensification Trials in Rectal Cancer: A Systematic Review

PURPOSE

Multiple phase 2 trials of neoadjuvant treatment intensification in locally advanced rectal cancer have reported promising efficacy signals, but these have not translated into improved cancer outcomes in phase 3 trials. Improvements in phase 2 trial design are needed to reduce these false-positive signals. This systematic review evaluated the design of phase 2 trials of neoadjuvant long-course radiation or chemoradiation therapy treatment intensification in locally advanced rectal cancer.

METHODS AND MATERIALS

The PubMed, EMBASE, MEDLINE, and Cochrane Library databases were searched for published phase 2 trials of neoadjuvant treatment intensification from 2004 to 2016. Trial clinical design and outcomes were assessed, with statistical design and compliance rated using a previously published system. Multivariable meta-regression analysis of pathologic complete response (pCR) was conducted.

RESULTS

We identified 92 eligible trials. Patients with American Joint Committee on Cancer stage II and III equivalent disease were eligible in 87 trials (94.6%). In 43 trials (46.7%), local staging on magnetic resonance imaging was mandated. Only 12 trials (13.0%) were randomized, with 8 having a standard-treatment control arm. Just 51 trials (55.4%) described their statistical design, with 21 trials (22.8%) failing to report their sample size derivation. Most trials (n=84, 91.3%) defined a primary endpoint, but 15 different primary endpoints were used. All trials reported pCR rates. Only 38 trials (41.3%) adequately reported trial statistical design and compliance. Meta-analysis revealed a pooled pCR rate of 17.5% (95% confidence interval, 15.7%-19.4%) across treatment arms of neoadjuvant long-course radiation or chemoradiation therapy treatment intensification and substantial heterogeneity among the reported effect sizes (I² = 55.3%, P<.001). Multivariable meta-regression analysis suggested increased pCR rates with higher radiation therapy doses (adjusted P=.025).

CONCLUSIONS

Improvement in the design of future phase 2 rectal cancer trials is urgently required. A significant increase in randomized trials is essential to overcome selection bias and determine novel schedules suitable for phase 3 testing. This systematic review provides key recommendations to guide future treatment intensification trial design in rectal cancer.

Surgical outcomes of post chemoradiotherapy unresectable locally advanced rectal cancers improve with interim chemotherapy, is FOLFIRINOX better than CAPOX?

BACKGROUND

Role of chemotherapy in patients who continue to have unresectable disease after pre-operative chemo-radiotherapy (CRT) remains largely unaddressed.

METHODS

Patients with LA rectal cancer from January 2013 to June 2015 were evaluated. Post-CRT, patients, who were deemed unresectable, were considered for further interim chemotherapy (i-CT).

RESULTS

Seventy six patients (15%) with median age of 38.5 years received i-CT after CRT. About 61.8% patients receiving i-CT managed to undergo a definitive surgery and the extent of surgery was reduced in 48.7% patients. With the median follow up of 19 months, the estimated 2-year event free survival (EFS) of 48% and OS was 56%. The estimated 2-year OS was 81% in mucinous tumors whereas it was 44.4% in signet ring pathology (P=0.045). The 2-year OS of 86% for whom surgery was done vs. 38% (2-year OS) in whom surgery was not done (P=0.011). Survival was better in conservative surgery group vs. total pelvic exenteration (TPE) vs. no surgery (2-year OS: 84% vs. 59.1% vs. 38%; P=0.033). In the CAPE-OX group, 71.4% (14/23) underwent surgery whereas 75.9% (29/47) in the 5-FU plus irinotecan plus oxaliplatin (FOLFIRINOX) group with EFS (P=0.570) and OS (P=0.120). In conservative surgery group, OS was better in FOLFIRINOX (2-year OS: 95.7%) vs. capecitabine plus oxaliplatin (CAPOX) (2-year OS: 70%) (P=0.012).

CONCLUSIONS

i-CT can lead to improved resection rates, improved survivals and downstaging with acceptable toxicity. FOLFIRINOX appears to better over CAPOX, specifically in whom conservative surgery is feasible.

Phase 1 Study of Preoperative Chemoradiation Therapy With Temozolomide and Capecitabine in Patients With Locally Advanced Rectal Cancer

PURPOSE

Preoperative chemoradiation therapy (CRT) with capecitabine is a standard treatment strategy in patients with locally advanced rectal cancer (LARC). Temozolomide improves the survival of patients with glioblastoma with hypermethylated O(6)-methylguanine DNA methyltransferase (MGMT); MGMT hypermethylation is one of the colorectal carcinogenesis pathways. We aimed to determine the dose-limiting toxicity (DLT) and recommended dose (RD) of temolozomide in combination with capecitabine-based preoperative CRT for LARC.

METHODS AND MATERIALS

Radiation therapy was delivered with 45 Gy/25 daily fractions with coned-down boost of 5.4 Gy/3 fractions. Concurrent chemotherapy comprised fixed and escalated doses of capecitabine and temozolomide, respectively. The MGMT hypermethylation was evaluated in pretreatment tumor samples. This trial is registered with ClinicalTrials.gov with the number NCT01781403.

RESULTS

Twenty-two patients with LARC of cT3-4N0 or cTanyN1-2 were accrued. Dose level 3 was chosen as the RD because DLT was noticeably absent in 10 patients treated up to dose level 3. An additional 12 patients were recruited in this group. Grade III adverse events were noted, and pathologic complete response (pCR) was observed in 7 patients (31.8%); MGMT hypermethylation was detected in 16. The pCR rate was 37.5% and 16.7% in the hypermethylated and unmethylated MGMT groups, respectively (P=.616).

CONCLUSIONS

There was a tendency toward higher pCR rates in patients with hypermethylated MGMT. Future randomized studies are therefore warranted.

CAPIRI-IMRT: a phase II study of concurrent capecitabine and irinotecan with intensity-modulated radiation therapy for the treatment of recurrent rectal cancer

BACKGROUND

This study investigated the local effect and acute toxicity of irinotecan and capecitabine with concurrent intensity-modulated radiation therapy (IMRT) for the treatment of recurrent rectal cancer without prior pelvic irradiation.

METHODS

Seventy-one patients diagnosed with recurrent rectal cancer who did not previously receive pelvic irradiation were treated in our hospital from October 2009 to July 2012. Radiotherapy was delivered to the pelvis, and IMRT of 45 Gy (1.8 Gy per fraction), followed by a boost of 10 Gy to 16 Gy (2 Gy per fraction), was delivered to the recurrent sites. The concurrent chemotherapy regimen was 50 mg/m(2) irinotecan weekly and 625 mg/m(2) capecitabine twice daily (Mon-Fri). Radical surgery was recommended for medically fit patients without extra-pelvic metastases. The patients were followed up every 3 months. Tumor response was evaluated using CT/MRIs according to the RECIST criteria or postoperative pathological findings. NCI-CTC 3.0 was used to score the toxicities.

RESULTS

Forty-eight patients (67.6%) had confirmed recurrent rectal cancer without extra pelvic metastases, and 23 patients (32.4%) had extra pelvic metastases. Fourteen patients (19.7%) underwent radical resections (R0) post-chemoradiation. A pathologic complete response was observed in 7 of 14 patients. A clinical complete response was observed in 4 patients (5.6%), and a partial response was observed in 22 patients (31.0%). Only 5 patients (7.0%) showed progressive disease during or shortly after treatment. Of 53 symptomatic patients, clinical complete and partial symptom relief with chemoradiation was achieved in 56.6% and 32.1% of patients, respectively. Only 2 patients (2.8%) experienced grade 4 leukopenia. The most common grade 3 toxicity was diarrhea (16 [22.5%] patients). The median follow-up was 31 months. The cumulative local progression-free survival rate was 74.2% and 33.9% at 1 and 3 years after chemoradiation, respectively. The cumulative total survival rate was 80.1% and 36.5% at 1 and 3 years after chemoradiation, respectively.

CONCLUSIONS

This study revealed that concurrent irinotecan and capecitabine with IMRT significantly relieves local symptoms and exhibits promising efficacy with manageable toxicities in recurrent rectal cancer without prior pelvic irradiation. Improving the rate of R0 resections will be investigated in a future study.

How can we determine the best neoadjuvant chemoradiotherapy regimen for rectal cancer?

SUMMARY 

The current management of patients with clinically defined ‘locally advanced rectal cancer’ often involves fluoropyrimidine-based preoperative chemoradiotherapy (CRT) followed by total mesorectal excision. The focus remains primarily on reducing local recurrence, and improving survival, with organ preservation an increasing target. The best neoadjuvant CRT is the most effective regimen, balanced against the tolerability and late functional consequences, which should be selected for the individual according to their individual risk of local and distant recurrence. Hence, what makes the best neoadjuvant treatment depends on the activity and toxicity of the particular schedule, the aims of treatment, the individual disease characteristics and the individual patient pharmacogenomics. Current research efforts focus on enhancing the efficacy of CRT by integrating additional cytotoxics and biologically targeted agents.

Impact of perineural and lymphovascular invasion on oncological outcomes in rectal cancer treated with neoadjuvant chemoradiotherapy and surgery

BACKGROUND

The prognostic significance of perineural and/or lymphovascular invasion (PLVI) and its relationship with tumor regression grade (TRG) in patients with locally advanced rectal cancer (LARC) treated with neoadjuvant chemoradiotherapy (CRT) and surgery.

METHODS

A total of 324 patients with LARC were treated with CRT and operated on between January 1992 and June 2007. Tumors were graded using a quantitative 5-grade TRG classification and the presence of PLVI was histologically studied.

RESULTS

At a median follow-up of 79.0 months (range 3-250 months), a total of 80 patients (24.7%) relapsed. The observed 5- and 10-year overall survival (OS) was 83.2 and 74.9 %, respectively. The 5- and 10-year disease-free survival (DFS) was 75.1 and 71.4%, respectively. A significant correlation was found between the TRG and survival (log rank, p < 0.001). The 10-year OS was 32.7% for grade 1, 63.8% for grade 2, 75.0% for grade 3, 90.4% for grade 3+, and 96.0%,for grade 4. The 10-year DFS was 31.8% for grade 1, 58.6% for grade 2, 70.4% for grade 3, 88.4% for grade 3+, and 97.1% for grade 4. In patients with PLVI, the TRG had no impact on survival. When excluding patients with PLVI, the TRG was an independent prognostic factor for OS and DFS.

CONCLUSIONS

The presence of PLVI is a more powerful prognostic factor than TRG in LARC patients treated with neoadjuvant CRT followed by surgery. PLVI denotes an aggressive phenotype, suggesting that these patients may benefit from adjuvant systemic therapy.

Comparison of two preoperative chemoradiotherapy regimens for locally advanced rectal cancer: capecitabine alone versus capecitabine plus irinotecan

BACKGROUND

To compare the short-term tumor response and long-term clinical outcome of two preoperative chemoradiotherapy (CRT) regimens for locally advanced rectal cancer.

METHODS

This study included 231 patients scheduled for preoperative CRT using two chemotherapeutic protocols from April 2003-August 2006. Pelvic radiotherapy (50.4 Gy) was delivered concurrently with capecitabine (n = 148) or capecitabine/irinotecan (n = 83). Surgery was performed 4-8 weeks after CRT completion. Tumor responses to CRT were assessed using both radiologic and pathologic measurements. Radiologic responses were evaluated by magnetic resonance volumetry, which was performed at the initial work-up and after completion of preoperative CRT just before surgery. Pathologic responses were assessed with downstaging (ypStage 0-1) and grading tumor regression. Clinical outcomes were evaluated in terms of local control, relapse-free survival, and overall survival rates.

RESULTS

Radiologic examination demonstrated that tumor volume decreased by 65.6% in the capecitabine group and 66.8% capecitabine/irinotecan group (p = 0.731). Postoperative pathologic stage determination showed that tumor downstaging occurred in 44.1% of the capecitabine group and 48.6% of the capecitabine/irinotecan group (p = 0.538). The sum of tumor regression grade 3 (near complete response) and 4 (complete response) after CRT were 28.6% in the capecitabine group and 37.5% in the capecitabine/irinotecan group (p = 0.247). There were no significant differences between the two groups in 5-year local control (91.7% vs. 92.5%; p = 0.875), relapse-free survival (80.8% vs. 77.2%; p = 0.685), and overall survival (88.4% vs. 90.4%; p = 0.723).

CONCLUSIONS

This study revealed no differences in the short-term tumor response and long-term clinical outcome between preoperative capecitabine and capecitabine/irinotecan CRT regimens for locally advanced rectal cancer.

Phase II study of concurrent capecitabine and external beam radiotherapy for pain control of bone metastases of breast cancer origin

Background

Pain from bone metastases of breast cancer origin is treated with localized radiation. Modulating doses and schedules has shown little efficacy in improving results. Given the synergistic therapeutic effect reported for combined systemic chemotherapy with local radiation in anal, rectal, and head and neck malignancies, we sought to evaluate the tolerability and efficacy of combined capecitabine and radiation for palliation of pain due to bone metastases from breast cancer.

Methodology/Principal Findings

Twenty-nine women with painful bone metastases from breast cancer were treated with external beam radiation in 10 fractions of 3 Gy, 5 fractions a week for 2 consecutive weeks. Oral capecitabine 700 mg/m² twice daily was administered throughout radiation therapy. Rates of complete response, defined as a score of 0 on a 10-point pain scale and no increase in analgesic consumption, were 14% at 1 week, 38% at 2 weeks, 52% at 4 weeks, 52% at 8 weeks, and 48% at 12 weeks. Corresponding rates of partial response, defined as a reduction of at least 2 points in pain score without an increase in analgesics consumption, were 31%, 38%, 28%, 34% and 38%. The overall response rate (complete and partial) at 12 weeks was 86%. Side effects were of mild intensity (grade I or II) and included nausea (38% of patients), weakness (24%), diarrhea (24%), mucositis (10%), and hand and foot syndrome (7%).

Conclusions/Significance

External beam radiation with concurrent capecitabine is safe and tolerable for the treatment of pain from bone metastases of breast cancer origin. The overall and complete response rates in our study are unusually high compared to those reported for radiation alone. Further evaluation of this approach, in a randomized study, is warranted.

Trial Registration

ClinicalTrials.gov NCT01784393NCT01784393

An update on preoperative radiotherapy for locally advanced rectal cancer

Even in patients undergoing an optimal surgical technique (e.g., total mesorectal excision), radiotherapy provides a significant benefit in the local control of rectal cancer. Compared with postoperative treatment, chemoradiotherapy given preoperatively has been shown to decrease local recurrence rates and toxicity. Additionally, preoperative chemoradiotherapy permits the early identification of tumor responses to this cytotoxic treatment by surgical pathology. Pathological parameters reflecting the tumor response to chemoradiotherapy have been shown to be surrogate markers for long-term clinical outcomes. Post-chemoradiotherapy downstaging from cStage II-III to ypStage 0-I indicates a favorable prognosis, with no difference between ypStage 0 and ypStage I. Research is ongoing to develop useful tools (clinical, molecular, and radiological) for clinical determination of the pathologic chemoradiotherapeutic response before surgery, and possibly even before preoperative treatment. In the future, risk-adapted strategies, including intensification of preoperative therapy, conservative surgery, or the selective administration of postoperative chemotherapy, will be realized for locally-advanced rectal cancer patients based on their response to preoperative chemoradiotherapy.

KRAS mutation status and clinical outcome of preoperative chemoradiation with cetuximab in locally advanced rectal cancer: a pooled analysis of 2 phase II trials

PURPOSE

Cetuximab-containing chemotherapy is known to be effective for KRAS wild-type metastatic colorectal cancer; however, it is not clear whether cetuximab-based preoperative chemoradiation confers an additional benefit compared with chemoradiation without cetuximab in patients with locally advanced rectal cancer.

METHODS AND MATERIALS

We analyzed EGFR, KRAS, BRAF, and PIK3CA mutation status with direct sequencing and epidermal growth factor receptor (EGFR) and Phosphatase and tensin homolog (PTEN) expression status with immunohistochemistry in tumor samples of 82 patients with locally advanced rectal cancer who were enrolled in the IRIX trial (preoperative chemoradiation with irinotecan and capecitabine; n=44) or the ERBIRIX trial (preoperative chemoradiation with irinotecan and capecitabine plus cetuximab; n=38). Both trials were similarly designed except for the administration of cetuximab; radiation therapy was administered at a dose of 50.4 Gy/28 fractions and irinotecan and capecitabine were given at doses of 40 mg/m2 weekly and 1650 mg/m2/day, respectively, for 5 days per week. In the ERBIRIX trial, cetuximab was additionally given with a loading dose of 400 mg/m2 on 1 week before radiation, and 250 mg/m2 weekly thereafter.

RESULTS

Baseline characteristics before chemoradiation were similar between the 2 trial cohorts. A KRAS mutation in codon 12, 13, and 61 was noted in 15 (34%) patients in the IRIX cohort and 5 (13%) in the ERBIRIX cohort (P=.028). Among 62 KRAS wild-type cancer patients, major pathologic response rate, disease-free survival and pathologic stage did not differ significantly between the 2 cohorts. No mutations were detected in BRAF exon 11 and 15, PIK3CA exon 9 and 20, or EGFR exon 18-24 in any of the 82 patients, and PTEN and EGFR expression were not predictive of clinical outcome.

CONCLUSIONS

In patients with KRAS wild-type locally advanced rectal cancer, the addition of cetuximab to the chemoradiation with irinotecan plus capecitabine regimen was not associated with improved clinical outcome compared with chemoradiation without cetuximab.

Long-term follow-up of preoperative pelvic radiation therapy and concomitant boost irradiation in locally advanced rectal cancer patients: a multi-institutional phase II study (KROG 04-01)

PURPOSE

To perform a prospective phase II study to investigate the efficacy and safety of preoperative pelvic radiation therapy and concomitant small-field boost irradiation with 5-fluorouracil and leucovorin for 5 weeks in locally advanced rectal cancer patients.

METHODS AND MATERIALS

Sixty-nine patients with locally advanced, nonmetastatic, mid-to-lower rectal cancer were prospectively enrolled. They had received preoperative chemoradiation therapy and total mesorectal excision. Pelvic radiation therapy of 43.2 Gy in 24 fractions plus concomitant boost radiation therapy of 7.2 Gy in 12 fractions was delivered to the pelvis and tumor bed for 5 weeks. Two cycles of 5-fluorouracil and leucovorin were administered for 3 days in the first and fifth week of radiation therapy. The pathologic response, survival outcome, and treatment toxicity were evaluated for the study endpoints.

RESULTS

Of 69 patients, 8 (11.6%) had a pathologically complete response. Downstaging rates were 40.5% for T classification and 68.1% for N classification. At the median follow-up of 69 months, 36 patients have been followed up for more than 5 years. The 5-year disease-free survival (DFS) and overall survival rates were 66.0% and 75.3%, respectively. Higher pathologic T (P=.045) and N (P=.032) classification were significant adverse prognostic factors for DFS, and high-grade histology was an adverse prognostic factor for both DFS (P=.025) and overall survival (P=.031) on the multivariate analysis. Fifteen patients (21.7%) experienced grade 3 or 4 acute toxicity, and 7 patients (10.1%) had long-term toxicity.

CONCLUSION

Preoperative pelvic radiation therapy with concomitant boost irradiation with 5-fluorouracil and leucovorin for 5 weeks showed acceptable acute and long-term toxicities. However, the benefit of concomitant small-field boost irradiation for 5 weeks in rectal cancer patients was not demonstrated beyond conventional irradiation for 6 weeks in terms of tumor response and survival.

Systematic review and meta-analysis of outcomes following pathological complete response to neoadjuvant chemoradiotherapy for rectal cancer

BACKGROUND

Following neoadjuvant chemoradiotherapy (CRT) and interval proctectomy, 15-20 per cent of patients are found to have a pathological complete response (pCR) to combined multimodal therapy, but controversy persists about whether this yields a survival benefit. This systematic review evaluated current evidence regarding long-term oncological outcomes in patients found to have a pCR to neoadjuvant CRT.

METHODS

Three major databases (PubMed, MEDLINE and the Cochrane Library) were searched. The systematic review included all original articles reporting long-term outcomes in patients with rectal cancer who had a pCR to neoadjuvant CRT, published in English, from January 1950 to March 2011.

RESULTS

A total of 724 studies were identified for screening. After applying inclusion and exclusion criteria, 16 studies involving 3363 patients (1263 with pCR and 2100 without) were included (mean age 60 years, 65·0 per cent men). Some 73·4 per cent had a sphincter-saving procedure. Mean follow-up was 55·5 (range 40-87) months. For patients with a pCR, the weighted mean local recurrence rate was 0·7 (range 0-2·6) per cent. Distant failure was observed in 8·7 per cent. Five-year overall and disease-free survival rates were 90·2 and 87·0 per cent respectively. Compared with non-responders, a pCR was associated with fewer local recurrences (odds ratio (OR) 0·25; P = 0·002) and less frequent distant failure (OR 0·23; P < 0·001), with a greater likelihood of being alive (OR 3·28; P = 0·001) and disease-free (OR 4·33, P < 0·001) at 5 years.

CONCLUSION

A pCR following neoadjuvant CRT is associated with excellent long-term survival, with low rates of local recurrence and distant failure.

A phase I trial of S-1 with concurrent radiotherapy in patients with locally recurrent rectal cancer

BACKGROUND

The purpose of this phase I trial of S-1 chemotherapy in combination with pelvic radiotherapy for locally recurrent rectal cancer was to determine the maximum tolerated dose (MTD), recommended dose (RD), and dose-limiting toxicity (DLT) of S-1.

METHODS

We enrolled 9 patients between April 2005 and March 2009. Radiotherapy (total dose, 60 Gy in 30 fractions) was given to the gross local recurrent tumor and pelvic nodal metastases using three-dimensional radiotherapy planning. We administered oral S-1 twice a day on days 1-14 and 22-35 during radiotherapy. The dose of S-1 was initially 60 mg/m(2)/day and was increased to determine the MTD and RD for this regimen.

RESULTS

DLT appeared at dose level 2 (70 mg/m(2)/day) in 2 patients, who experienced grade 3 enterocolitis and consequently required suspension of S-1 administration for longer than 2 weeks. Hematological toxicity was mild and reversible. At the initial evaluation, complete regression and partial regression were seen in 1 patient (11%) and 2 patients (22%), respectively.

CONCLUSION

This phase I trial of S-1 chemotherapy with pelvic radiotherapy for locally recurrent rectal cancer revealed that the MTD for S-1 was 70 mg/m(2)/day and the RD was 60 mg/m(2)/day.