A multicenter phase II study of preoperative chemoradiotherapy with S-1 plus oxaliplatin for locally advanced rectal cancer (SHOGUN trial)

Role of Oxaliplatin in the Neoadjuvant Concurrent Chemoradiotherapy in Locally Advanced Rectal Cancer: a Review of Evidence

The treatment of locally advanced rectal cancer (LARC) is a challenging situation for radiation oncologists and colorectal surgeons. Most current approaches recommend neoadjuvant fluorouracil or capecitabine-based chemoradiotherapy followed by surgery as a standard of care. Intensification of concurrent chemotherapy by adding oxaliplatin to fluorouracil or capecitabine backbone to get better outcomes is the matter that has remained unresolved. In this review, we searched Medline and Google Scholar databases and selected 28 prospective phase II and III clinical trials that addressed this question. We discussed the potential advantages and drawbacks of incorporating oxaliplatin into concurrent chemoradiation therapy. We tried to define whether adding oxaliplatin to concurrent chemoradiation with excellent performance and high-risk features benefits some subpopulations. The available literature suggests that by adding oxaliplatin there are some benefits in enhancing response to neoadjuvant chemoradiotherapy, however, without any translated improvements in long-term outcomes including overall and disease-free survival.

Impact of Fluoropyrimidine and Oxaliplatin-based Chemoradiotherapy in Patients With Locally Advanced Rectal Cancer

BACKGROUND/AIM

To evaluate the benefits of the addition of oxaliplatin (OX) to fluoropyrimidine (FP)-based neoadjuvant chemoradiotherapy (CRT) for patients with locally advanced rectal cancers (LARCs).

PATIENTS AND METHODS

We performed retrospective analyses comparing the pathological complete response (pCR) rate, overall survival (OS), recurrence-free survival (RFS), and local recurrence-free survival (LRFS) between FP-based and FP+OX-based CRT groups and for patients who had completed the CRT.

RESULTS

One hundred patients were included in the analyses: the pCR rate, OS, RFS, and LRFS were similar between these groups. The FP+OX group showed significantly more frequent incompleteness of the CRT compared to the FP group (p=0.049). Among the patients who had completed the CRT, the FP+OX group demonstrated significantly improved LRFS compared to the FP group (p=0.048).

CONCLUSION

The addition of OX to an FP regimen in neoadjuvant CRT for LARC may reduce local recurrence in patients who have achieved good compliance to CRT.

Effective dissection for rectal cancer with lateral lymph node metastasis based on prognostic factors and recurrence type

PURPOSE

There are no reports showing the significance and effective range of dissection for patients with lateral lymph node metastasis (LLNM). This study aimed to investigate the indications for lateral lymph node dissection (LLND) in patients with LLNM based on prognostic factors and recurrence types.

METHODS

We reviewed 379 patients with advanced rectal cancer who were treated with total mesorectal excision plus LLND. We analyzed background factors and survival times of patients who had LLNM to determine prognostic factors and recurrence types.

RESULTS

Pathological LLNM occurred in 44 (11.6%). Among patients with LLNM, the predictors of poor prognoses, according to univariate analysis, were > 3 node metastases, the presence of node metastasis on both sides, and spreading beyond the internal iliac lymph nodes. Moreover, LLNM beyond the internal iliac region was found to be an independent prognostic risk factor. Twenty-eight of the 44 patients with lateral lymph node metastasis (64%) relapsed, 22 of whom had distant metastases and 11 of whom experienced local recurrences. Among the latter group, nine (20%) and two (5%) had recurrences in the central and lateral pelvis, respectively.

CONCLUSION

The therapeutic benefit of resection was high, especially in patients with ≤ 3 positive lateral lymph nodes, one-sided bilateral lymph node areas, and positive nodes localized near the internal iliac artery.

Efficacy and tolerability of preoperative chemoradiotherapy with S-1 alone for locally advanced rectal cancer

Preoperative chemoradiotherapy with capecitabine or 5-fluorouracil is a standard treatment for locally advanced rectal cancer (LARC). S-1, a prodrug of 5-fluorouracil, is a candidate for this chemoradiotherapy regimen in Japan; however, treatment outcomes after S-1 treatment alone are not clear. This study aimed to assess the efficacy and tolerability of preoperative chemoradiotherapy with S-1 alone for LARC. We retrospectively evaluated 54 LARC patients who underwent preoperative chemoradiotherapy with S-1 alone in our institution between 2005 and 2017. The clinical tumor stage was cT2-3 in 31 patients and cT4 in 23 patients, and lymph node metastases were clinically evident in 31 patients. S-1, at a dose of 80 mg/m2/day, was orally administered during radiotherapy. A total dose of 45-50.4 Gy was delivered in 25-28 fractions (median: 50.4 Gy). Surgical resections were scheduled 6-10 weeks after chemoradiotherapy completion. The 3- and 5-year overall survival rates were 92.4 and 72.8%, respectively, with a median follow-up time of 51 months. The 3- and 5-year local control rates were 96.2 and 85.9%, respectively. A pathological complete response was observed in 7 patients (13.0%) at the time of surgery. Ten patients (18.5%) had grade 3 acute toxicities and 5 patients (9.3%) had grade 3 late toxicities. No grade 4 or 5 toxicities were observed. Preoperative chemoradiotherapy with S-1 alone followed by total mesorectal excision resulted in a low incidence of toxicities and comparable clinical results. Therefore, S-1 alone can be a treatment option for preoperative chemoradiotherapy in LARC patients.

A multicenter phase II trial of preoperative chemoradiotherapy with S-1 plus oxaliplatin and bevacizumab for locally advanced rectal cancer

BACKGROUND

We clarified the safety and efficacy of preoperative chemoradiotherapy for locally advanced rectal cancer using a multidrug regimen (S-1 + oxaliplatin + bevacizumab).

METHODS

This multicenter phase II trial involved 47 patients with locally advanced rectal cancer. All patients received S-1 orally (80 mg/m²/day on days 1-5, 8-12, 15-19, and 22-26) and infusions of oxaliplatin (50 mg/m² on days 1, 8, 15, and 22) and bevacizumab (5 mg/kg on days 1 and 15). The total radiation dose was 40 Gy delivered in daily fractions of 2 Gy via the four-field technique. The primary endpoint was the pathological complete response rate. The secondary endpoints were safety (incidence of adverse events) and clinical response, relapse-free survival, overall survival, local recurrence, R0 resection, downstaging, and treatment completion rates.

RESULTS

All 47 patients received chemoradiotherapy, and 44 patients underwent curative resection. Two patients refused surgery and selected a watch-and-wait strategy. The pathological complete response rate was 18.2% in patients who underwent curative resection. The clinical response rate was 91.3% in 46 patients. Concerning hematotoxicity, there was one grade 4 adverse event (2.1%) and seven grade 3 events (14.9%). Diarrhea was the most frequent non-hematotoxic event, and the grade 3 event rate was 25.5%.

CONCLUSIONS

Although preoperative chemoradiotherapy for patients with locally advanced rectal cancer using the S-1 + oxaliplatin + bevacizumab regimen did not achieve the expected pathological complete response rate, this regimen led to an improved clinical response rate.

Emerging trends in the treatment of rectal cancer

The conventional treatment for cT3-T4 or node-positive clinically resectable rectal cancer is long course preoperative chemoradiation followed by surgery and postoperative adjuvant chemotherapy. Disadvantages of this approach include possible overtreatment of patients, 6 weeks of daily radiation treatment, and undetected metastatic disease. There are a number of emerging trends which are changing this approach to treatment. Selected topics included in this manuscript include the selective use of pelvic radiation, the role of radiation for a positive radial margin, the interval between radiation and surgery, non-operative management, new chemoradiation regimens, short vs. long course radiation, and the role of postoperative adjuvant chemotherapy.

Clinical outcomes of preoperative chemoradiotherapy in octogenarian with locally advanced rectal cancer

The number of elderly patients who receive surgical treatment for rectal cancer has gradually increased with aging of the population. In recent years, preoperative chemoradiotherapy, followed by surgical treatment, has been widely used for treating patients with locally advanced rectal adenocarcinoma. The aim of the present study was to evaluate if preoperative chemoradiotherapy is efficacious and safe for the treatment of rectal cancer in patients older than 80 years. A total of 293 patients with rectal cancer, who received preoperative chemoradiotherapy from 2007 to 2017, were studied. Comorbidities and the short- and long-term outcomes in elderly patients (aged ≥80 years old) were investigated and compared to younger patients. The elderly group comprised of 17 patients (5.8%). Pulmonary disease was the most common comorbidity (23.5%). No significant difference between the two groups regarding the rate of completeness of chemoradiotherapy was detected (P=0.26). Curative resection was performed in 14 patients in the elderly group and 252 patients in the younger group. Among 7 patients from both groups who could not receive curative resection due to their poor general condition, 4 patients had decreased lower respiratory function due to pneumonia (3 patients) or chronic obstructive pulmonary disease (1 patient). Morbidity and mortality rates were similar in elderly and younger groups (35.7% vs. 27.0%, 0% vs. 0%, respectively; P=0.54, P=1.00). No significant difference was found regarding recurrence between the two groups (P=1.00). To conclude, preoperative chemoradiotherapy in elderly patients with rectal cancer is safe and well tolerated.

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.

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.

Recent advances in neoadjuvant chemoradiotherapy in locally advanced rectal cancer

Preoperative chemoradiotherapy (CRT) has been actively used in Europe and the United States to treat advanced low rectal cancer, and provides excellent local control. In Japan, however, the standard treatment is lateral lymph node dissection, and to date CRT has not been actively used. In recent years, an increasing number of Japanese institutions have been using preoperative CRT to treat locally advanced rectal cancer. In this review, we describe the latest trends in CRT under five headings: short-course or long-course radiation, efforts to improve combined chemotherapy, the addition of preoperative adjuvant chemotherapy, the watch and wait strategy, and the significance of lateral lymph node dissection in patients receiving CRT.

Neoadjuvant Treatment Strategies: Advanced Radiation Alternatives

Long-course chemoradiation therapy (CRT) has been the standard approach for locally advanced rectal tumors. Neoadjuvant CRT is associated to improved local disease control, with less toxicity when compared with adjuvant CRT, as well as the chance for pathologic complete response. The CRT regimens have improved over the past years. This article will examine selected controversies, including novel chemoradiation regimens, duration of radiation (short vs. long course), and radiation techniques such as intensity-modulated radiation therapy (IMRT).

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.

Comparison of volumetric-modulated arc therapy using simultaneous integrated boosts (SIB-VMAT) of 45 Gy/55 Gy in 25 fractions with conventional radiotherapy in preoperative chemoradiation for rectal cancers: a propensity score case-matched analysis

Background and purpose

The aim of this retrospective study was to compare volumetric-modulated arc therapy using simultaneous integrated boosts (SIB-VMAT) of 45 Gy/55 Gy in 25 fractions with three-dimensional conformal radiotherapy (3D–CRT) in preoperative chemoradiation for rectal cancers.

Methods and materials

In the propensity score-matching analysis of 1:2, we selected 60 patients from the SIB-VMAT group and 120patients from the 3D–CRT group matched pairings out of 145 patients between 2005 and 2015. The regimen of concurrent combined chemotherapy was oral uracil/tegafur plus leucovorin with/without irinotecan.

Results

There were no significant differences between the two groups, in pathological complete response rates (pCR) (11% in the 3D–CRT group vs. 17% in the SIB-VMAT group, P = 0.39), pathological response rates (44% vs. 60%, P = 0.77), disease-free survival (P = 0.32), or local control (P = 0.52). The SIB-VMAT method marginally improved the rate of pathological grade 2–3 effects and the OS was significantly better in patients with grade 2–3 effects. Recurrence was seen in 36 patients (30%) in the 3D–CRT group and 19 patients (32%) in the SIB-VMAT group. The first distant recurrence site in the SIB-VMAT group was liver in 6 patients and lung in 8 patients. The obvious radiation-induced late toxicity in the SIB-VMAT group was recto-vesical fistula in two patients.

Conclusions

The SIB-VMAT may be a promising method for preoperative CRT of rectal cancer.