Study protocol of the SACURA trial: a randomized phase III trial of efficacy and safety of UFT as adjuvant chemotherapy for stage II colon cancer

Predictive modelling for high-risk stage II colon cancer using auto-artificial intelligence

BACKGROUND

Recently, stratification of high-risk stage II colon cancer (CC) and the need for adjuvant chemotherapy have been the focus of attention. The aim of this retrospective study was to define high-risk factors for recurrent stage II CC using Prediction One auto-artificial intelligence (AI) software and develop a new predictive model for high-risk stage II CC.

METHODS

The study included 259 consecutive pathological stage II CC patients undergoing curative resection at our institution between January 2000 and December 2016. Prediction One software with five-fold cross-validation was used to create a predictive model and receiver operating characteristic (ROC) curve. Predictive accuracy of AI was evaluated using the area under the ROC curve (AUC). We also evaluated the importance of variables (IOV) using a method based on permutation feature importance (IOV > 0.01 defined high-risk factors) to evaluate disease-free survival (DFS).

RESULTS

The median observation period was 6.1 (range = 0.3-15.8) years. Thirty-seven patients had recurrence (14.3%); the AUC of the AI model was 0.775. Preoperative carcinoembryonic antigen > 5.0 ng/mL (IOV = 0.047), venous invasion (IOV = 0.014), and obstruction (IOV = 0.012) were high-risk factors contributing to cancer recurrence. Patients with 2-3 high-risk factors had lower 5-year DFS than those with 0-1 factor (87.4% vs 62.7%, p < 0.001).

CONCLUSIONS

We developed a new predictive model that could predict recurrent high-risk stage II CC with high probability using auto-AI Prediction One software. Patients with ≥ 2 of the aforementioned factors are considered to have high risks for recurrent stage II CC and may benefit from adjuvant chemotherapy.

Histopathological atlas of desmoplastic reaction characterization in colorectal cancer

Emergent scientific evidence indicates the central role of cancer-associated fibroblasts in determining whether the microenvironment of cancer works as friend or foe of the host; however, there is no unified histological evaluation framework of fibrotic stroma in colorectal cancers. Myxoid stroma and keloid-like collagen are site-specific histopathological features generated by cancer-associated fibroblasts, which appear exclusively in the tumor front during desmoplastic reaction. On the basis of these two stromal components, desmoplastic reaction is categorized into three patterns-immature, intermediate and mature-using hematoxylin and eosin staining. In January 2020, a prospective randomized clinical trial, JCOG1805, to elucidate the value of adjuvant chemotherapy in stage II colorectal cancer patients with pathological risk factors of recurrence was launched in Japan, in which intermediate/immature desmoplastic reaction is one of the four risk factors selected as inclusion criteria. This paper covers the diagnostic criteria for the desmoplastic reaction classification being used in the JCOG1805 study.

Prognostic value of desmoplastic reaction characterisation in stage II colon cancer: prospective validation in a Phase 3 study (SACURA Trial)

BACKGROUND

The characterisation of desmoplastic reaction (DR) has emerged as a new, independent prognostic determinant in colorectal cancer. Herein, we report the validation of its prognostic value in a randomised controlled study (SACURA trial).

METHODS

The study included 991 stage II colon cancer patients. DR was classified by the central review as Mature, Intermediate or Immature based on the presence of hyalinised collagen bundles and myxoid stroma at the desmoplastic front. All clinical and pathological data, including DR characterisations, were prospectively recorded and analysed 5 years after the completion of the registration.

RESULTS

The five-year relapse-free survival (RFS) rate was the highest in the Mature group (N = 638), followed by the Intermediate (N = 294) and Immature groups (N = 59). Multivariate analysis revealed that DR classification was an independent prognostic factor, and based on Harrell's C-index, the Cox model for predicting RFS was significantly improved by including DR. In the conditional inference tree analysis, DR categorisation was the first split factor for predicting RFS, followed by T-stage, microsatellite instability status and budding.

CONCLUSIONS

Histological categorisation of DR provides important prognostic information that could contribute to the efficient selection of stage II colon cancer patients who would benefit from postoperative adjuvant therapy.

Optimal Criteria for G3 (Poorly Differentiated) Stage II Colon Cancer: Prospective Validation in a Randomized Controlled Study (SACURA Trial)

Grade 3 (G3, poorly differentiated) is an important treatment-decision factor in stage II colon cancer, but no unified diagnostic criteria are established. According to previous studies, an intratumoural poorly differentiated area with no glandular formation (POR) that fills the microscopic field of a ×40 objective lens was an essential factor that defined G3. We aimed to prospectively validate this in a randomized controlled study of adjuvant chemotherapy (SACURA trial). We enrolled 991 patients with stage II colon cancer. POR was graded according to the ×40 objective lens rule and the intensity of poorly differentiated clusters (Grade), and its prognostic power was compared with that of the conventional tumor grade on the basis of predominant histology rule (Grade). According to Grade, 313, 526, and 152 tumors were classified as G1, G2, and G3, respectively, and the 5-year relapse-free survival (RFS) rates were 91.1%, 82.9%, and 74.7%, respectively (P<0.0001). When G3 and G3 were alternatively added to the prognostic model consisting of 8 conventional factors, only G3 was a significant factor for RFS (P=0.040, Wald test). The adverse impact of G3 on RFS was greater in the microsatellite stable/microsatellite instability-low subset than that in the full analysis set. In the microsatellite stable/microsatellite instability-low subset, the 5-year RFS rate of patients with G3 tumors in the chemotherapy group achieved greater improvement (9.1%) than the surgery-alone group. The least differentiation policy with the ×40 objective lens rule may be highlighted as the diagnostic criterion for G3 because of its validated prognostic value.

Prospective Multicenter Study on the Prognostic and Predictive Impact of Tumor Budding in Stage II Colon Cancer: Results From the SACURA Trial

PURPOSE

The International Union Against Cancer highlighted tumor budding as a tumor-related prognostic factor. International assessment criteria for tumor budding were recently defined by the 2016 International Tumor Budding Consensus Conference (ITBCC2016). This study aimed to clarify the prognostic and predictive values of tumor budding in a randomized controlled trial evaluating the superiority of adjuvant chemotherapy with oral tegafur-uracil over surgery alone for stage II colon cancer (SACURA trial; ClinicalTrials.gov identifier: NCT00392899).

PATIENTS AND METHODS

Between 2006 and 2010, we enrolled 991 patients from 123 institutions with stage II colon cancer. Tumor budding was diagnosed by central review on the basis of the criteria adopted in the ITBCC2016. We prospectively recorded all clinical and pathologic data, including the budding grade, and performed prognostic analyses after 5 years of completing the patients’ registration.

RESULTS

Of 991 tumors, 376, 331, and 284 were classified as BD1, BD2, and BD3, respectively; the 5-year relapse-free survival (RFS) rate was 90.9%, 85.1%, and 74.4%, respectively (P < .001), and ranged widely in T4 tumors (86.6% to 53.3%). The budding grade significantly correlated with recurrence in the liver, lungs, lymph nodes, and peritoneum (P < .001 to .01). Multivariable analysis revealed that budding and T stage exerted an independent impact on RFS, and on the basis of the Harrell concordance index, these two factors substantially contributed to the improvement of the Cox model for predicting RFS. Both the BD2 and BD3 groups demonstrated greater improvement in the 5-year recurrence rate in the adjuvant chemotherapy group than the surgery-alone group by approximately 5%, but the difference was statistically nonsignificant.

CONCLUSION

Tumor budding grade on the basis of the ITBCC2016 criteria should be routinely evaluated in pathologic practice and could improve the benefit of adjuvant chemotherapy for stage II colon cancer.

A randomised-controlled trial of 1-year adjuvant chemotherapy with oral tegafur-uracil versus surgery alone in stage II colon cancer: SACURA trial

BACKGROUND

Efficacy of adjuvant chemotherapy in patients with stage II colon cancer is still controversial. The SACURA trial is a randomised-controlled study evaluating the superiority of 1-year adjuvant treatment with oral tegafur-uracil (UFT) to surgery alone for stage II colon cancer.

METHODS

Patients were randomly assigned to the surgery-alone group or UFT group (UFT at 500-600 mg/day for 5 days, followed by 2-day rest, for 1 year). The primary end-point was disease-free survival (DFS). Target sample size was 2000, determined with one-sided alpha of 0.05, power of 0.9 and assumed hazard ratio (HR) 0.729.

RESULTS

A total of 1982 patients (997 in the surgery-alone group and 985 in the UFT group) were analysed. Median follow-up was 69.5 months, median age was 66 years and for stage IIA/IIB/IIC, the distribution was 84%/13%/3%. The 5-year DFS rate was 78.4% in the surgery-alone group and 80.2% in the UFT group. The HR for DFS was 0.91 (95% confidence interval [CI], 0.75-1.10; p = 0.31); superiority of UFT was not demonstrated. Approximately 9% of patients experienced second cancers, which consist 40.7% of the DFS events. The 5-year relapse-free and overall survival rates of the surgery-alone and UFT group were 84.6% and 87.2% (HR, 0.82; 95% CI, 0.65-1.04) and 94.3% and 94.5% (HR, 0.93; 95% CI, 0.66-1.31), respectively. Subgroup analysis failed to disclose superiority in prognosis of adding UFT to the patients with risk factors for recurrence.

CONCLUSIONS

Superiority of 1-year adjuvant UFT over surgery alone was not demonstrated in stage II colon cancer. Patients with risk factors for recurrence did not benefit from UFT.

TRIAL REGISTRATION

ClinicalTrials. Gov. #NCT00392899.

Japanese Society for Cancer of the Colon and Rectum Guidelines 2010 for the treatment of colorectal cancer: comparison with western guidelines

SUMMARY The Japanese Society for Cancer of the Colon and Rectum published guidelines (GLs) for the treatment of colorectal cancer in 2005 to show standard treatment strategies and to standardize the quality of care for patients with colorectal cancer in Japan. The Japanese Society for Cancer of the Colon and Rectum GLs differ from western GLs in terms of the scope of lymph node dissection (D3 dissection is standard in Japan), treatment strategy for ≥cT3 low rectal cancer (preoperative chemo-radiation vs lateral lymph node dissection), use of oxaliplatin-containing regimens as adjuvant chemotherapy for stage III diseases (first choice vs not first choice), use of neoadjuvant chemotherapy for resectable liver metastases (established vs not established treatment) and surveillance for recurrence (more intensive in Japan with shorter intervals between CT scans).

Prognostic factors of stage Ⅱa colon cancer

AIM: To investigate the prognostic factors of stage Ⅱa (pT3N0M0) colon cancer.

METHODS: The demographic, clinical and laboratory data for 161 patients with stage Ⅱa colon cancer treated with curative surgery alone at Peking University Cancer Hospital from January 2004 to June 2008 were reviewed retrospectively. Eighty-four valid cases were selected in this study based on inclusive and exclusive criteria. The 3-year disease-free survival (DFS) was tested by univariate and multivariate analyses to identify prognostic factors.

RESULTS: The overall 3-year DFS for the selected 84 cases was 88.1%. The 3-year DFS for patients with elevated CEA levels was significantly lower than those with normal CEA levels (76.5% vs 95.8%, P = 0.007). Multivariate analysis demonstrated that CEA level (OR = 8.013, 95% CI 1.573-40.817, P = 0.012), expression of Ki67 (OR = 3.298, 95% CI 0.799-13.610, P = 0.099), male gender (OR = 7.212, 95% CI 1.293-40.237, P = 0.024) and anemia (OR = 6.461, 95% CI 1.537-27.151, P = 0.011) were independent prognostic factors for the 3-year DFS. Stratified analysis revealed that elevated level of CEA combined with high expression of Ki67 was associated with a poorer prognosis (3-year DFS = 70%).

CONCLUSION: Elevated preoperative serum level of CEA and high expression of Ki67 in cancer tissue are predictors of poor prognosis for stage Ⅱa colon cancer. More intensive adjuvant treatment should be considered in patients with such high risk factors.

Clinical management of localized colon cancer with capecitabine

Large randomized trials demonstrated a benefit of adjuvant chemotherapy after resection of the primary colon cancer. It improves overall survival and reduces the risk of death, by 5% in UICC (Union Internationale Contre le Cancer) stage II and approximately 15%-20% in stage III. Fluoropyrimidines have been the standard drugs for the treatment of colon cancer since large randomized controlled trials demonstrated their efficacy and safety in treating patients suffering from this disease. Capecitabine is an orally administered fluoropyrimidine, which is preferably activated in tumor tissue to the active moiety 5-fluorouracil (5FU) and is cytotoxic through inhibition of DNA synthesis. It has proven equivalent efficacy and tolerability despite a changed toxicity profile compared to 5FU with less myelosuppression but more hand-and-foot syndrome. Capecitabine is well tolerated in elderly patients. The oral route of administration avoids frequent clinical visits as well as insertion of central venous catheters. The impact of the particular drug features on daily clinical practice is discussed in this review.