Effect of lymph node retrieval rates on the utilization of adjuvant chemotherapy in stage II colon cancer

Time-dependent Estimates of Recurrence and Survival in Colon Cancer: Clinical Decision Support System Tool Development for Adjuvant Therapy and Oncological Outcome Assessment

Unanswered questions remain in determining which high-risk node-negative colon cancer (CC) cohorts benefit from adjuvant therapy and how it may differ in an equal access population. Machine-learned Bayesian Belief Networks (ml-BBNs) accurately estimate outcomes in CC, providing clinicians with Clinical Decision Support System (CDSS) tools to facilitate treatment planning. We evaluated ml-BBNs ability to estimate survival and recurrence in CC. We performed a retrospective analysis of registry data of patients with CC to train–test–crossvalidate ml-BBNs using the Department of Defense Automated Central Tumor Registry (January 1993 to December 2004). Cases with events or follow-up that passed quality control were stratified into 1-, 2-, 3-, and 5-year survival cohorts. ml-BBNs were trained using machine-learning algorithms and k-fold crossvalidation and receiver operating characteristic curve analysis used for validation. BBNs were comprised of 5301 patients and areas under the curve ranged from 0.85 to 0.90. Positive predictive values for recurrence and mortality ranged from 78 to 84 per cent and negative predictive values from 74 to 90 per cent by survival cohort. In the 12-month model alone, 1,132,462,080 unique rule sets allow physicians to predict individual recurrence/mortality estimates. Patients with Stage II (N0M0) CC benefit from chemotherapy at different rates. At one year, all patients older than 73 years of age with T2–4 tumors and abnormal carcinoembryonic antigen levels benefited, whereas at five years, all had relative reduction in mortality with the largest benefit amongst elderly, highest T-stage patients. ml-BBN can readily predict which high-risk patients benefit from adjuvant therapy. CDSS tools yield individualized, clinically relevant estimates of outcomes to assist clinicians in treatment planning.

Exploration of exact significance of lymph node ratio and construction of a novel stage in colon cancer with no distant metastasis

Aim

Lymph node ratio (LNR) seems to be more precise than classic N stage in classifying cancer stage. Thus, we aim to construct a modified classification system based on LNR for colon cancer without distant metastasis.

Methods

This study enrolled two independent cohorts of patients. The primary cohort enrolled 2,152 patients from 2008 to 2013 in Zhongshan Hospital, Fudan University. The validation cohort consisted of 77,406 patients from the Surveillance, Epidemiology, and End Results (SEER) registry from 2004 to 2014. The inclusion criteria were: pathologically confirmed colon cancer, and American Joint Committee on Cancer (AJCC) stage I/II/III. The exclusion criteria included: incomplete follow-up information, rectal cancer, and multiple primary sites. The prognostic value of LNR for overall survival was evaluated. The cutoff value of LNR was determined by the X-tile. Predictive performance of modified classification was determined by the concordance index.

Results

After analysis, 0.05 and 0.50 were determined as the best threshold values of LNR. A value of <0.05, 0.05–0.50 and >0.50 was reclassified as the mN0, mN1 and mN2 stage. A modified classification based on mN0, mN1, and mN2 was further constructed for stage I/II/III colon cancer. C-index of the modified classification was statistically more precise than AJCC classification (0.687 versus 0.605, P<0.001). The same results can also be determined in the validation cohort (0.715 versus 0.640, P<0.001). Furthermore, a prognostic nomogram including independent factors was constructed. The constructed nomogram showed good performance according to the calibration curve.

Conclusion

The clinical value of LNR level was preferable to classic N stage in colon cancer patients. Our proposed classification based on LNR and AJCC T category can effectively differentiate patients with varied survival outcomes.

Lymphovascular invasion is a high risk factor for stage I/II colorectal cancer: a systematic review and meta-analysis

The prognostic value of lymphovascular invasion (LVI) in stage I/II colorectal cancer (CRC) does not reach a consensus. To systematically assess prognostic significance of LVI, databases of PubMed, Web of Science, and Embase were searched from inception up to 10 Dec 2016. The pooled hazard ratio (HR) and 95% confidence intervals (CI) were used to determine the prognostic effects. Nineteen relevant studies including 9881 total patients were enrolled. Our results showed that LVI is significantly associated with poor prognosis in overall survival (OS) (HR=2.15, 95 % CI=1.72–2.68, P < 0.01) and disease-free survival (DFS) (HR=1.73, 95% CI=1.50–1.99, P < 0.01), which is similar in stage II patients. Further subgroup analysis revealed that the significance of the association between LVI and worse prognosis in CRC patients is not affected by below factors, including geographic setting, LVI positive rate, treatment, tumor site, and quality of the study. The current meta-analysis suggests that LVI may be a poor prognostic factor for stage I/II CRC patients.

Clinical Significance of International Union Against Cancer pN Staging and Lymph Node Ratio in Node-Positive Colorectal Cancer after Advanced Lymph Node Dissection

BACKGROUND

Lymph node retrieval in colorectal cancer can be improved by using advanced histopathological techniques like methylene blue-assisted lymph node dissection, which results in a doubling or even tripling of the lymph node count in comparison with conventional lymph node dissection techniques. However, it is not clear whether the established lymph node staging systems are suitable for predicting patients' prognoses under these circumstances.

OBJECTIVE

The aim of this study was to determine whether the current lymph node staging systems are suitable when advanced dissection methods are used.

DESIGN

This is a retrospective cohort study.

SETTING AND PATIENTS

We formed a study group (methylene blue-assisted lymph node dissection) of 293 patients and a control group (conventional lymph node dissection) of 232 patients, each with node-positive cases. Conventional pN staging according to the International Union Against Cancer, seventh edition, and lymph node ratio were applied.

MAIN OUTCOME MEASURES

Overall survival was compared by using the different staging systems in a uni- and multivariable fashion.

RESULTS

The lymph node ratio values were reduced in the advanced methylene blue-assisted lymph node dissection group in comparison with the conventional lymph node dissection group (0.1 vs 0.3, p < 0.001). Although pN staging proved to be reliable, the cutoff values for lymph node ratio staging had to be adapted. The new cutoffs (0.07, 0.15, and 0.34) were prognostic. However, multivariable analysis revealed pN staging and vascular invasion, but not lymph node ratio, as independently prognostic in the methylene blue-assisted lymph node dissection group.

LIMITATIONS

The study group and historical control group are not perfectly balanced because the case number in the stage III subgroup of the control group is small.

CONCLUSIONS

pN staging proved to be a robust prognostic marker in colorectal cancer under the circumstances of improved lymph node harvest. After adaptation of the cutoff values, lymph node ratio is also prognostic but not superior to pN staging.

Stage migration vs immunology: The lymph node count story in colon cancer

Lymph node staging is of crucial importance for the therapy stratification and prognosis estimation in colon cancer. Beside the detection of metastases, the number of harvested lymph nodes itself has prognostic relevance in stage II/III cancers. A stage migration effect caused by missed lymph node metastases has been postulated as most likely explanation for that. In order to avoid false negative node staging reporting of at least 12 lymph nodes is recommended. However, this threshold is met only in a minority of cases in daily practice. Due to quality initiatives the situation has improved in the past. This, however, had no influence on staging in several studies. While the numbers of evaluated lymph nodes increased continuously during the last decades the rate of node positive cases remained relatively constant. This fact together with other indications raised doubts that understaging is indeed the correct explanation for the prognostic impact of lymph node harvest. Several authors assume that immune response could play a major role in this context influencing both the lymph node detectability and the tumor’s behavior. Further studies addressing this issue are need. Based on the findings the recommendations concerning minimal lymph node numbers and adjuvant chemotherapy should be reconsidered.

Patterns of Colorectal Cancer Care in the United States: 1990-2010

BACKGROUND

Colorectal cancer (CRC) mortality has declined in the United States, in part because of advances in treatment. Few studies have evaluated the adoption of therapies and temporal changes in patterns of care.

METHODS

Patients age 20 years and older diagnosed with stages II/III CRC were randomly sampled from the population-based Surveillance, Epidemiology, and End Results (SEER) program in 1990-1991, 1995, 2000, 2005, and 2010 (n = 7057). Therapy was obtained from medical records and physician verification. We described the receipt of chemotherapy and radiation therapy. Log-binomial regression was used to examine factors associated with therapy. All statistical tests were two-sided.

RESULTS

Chemotherapy receipt among colon cancer patients increased from 1990 (stage II: 22.5%; stage III: 56.3%) to 2005 (stage II: 32.1%; stage III: 72.4%) and declined slightly in 2010 (stage II: 29.3%; stage III: 66.4%). Stage III colon cancer patients who were older (vs <55 years, 75-79 years: risk ratio [RR] 0.81, 95% confidence interval [CI] = 0.71 to 0.91; ≥80 years: RR = 0.37, 95% CI = 0.28 to 0.47) or had a comorbidity score of 2 or higher (vs 0, RR = 0.56, 95% CI = 0.35 to 0.87) received chemotherapy less often. Receipt of radiation therapy by rectal cancer patients increased across all years from 45.5% to 66.1%. Increasing age (vs <55 years, 75-79 years: RR = 0.59, 95% CI = 0.47 to 0.74; ≥80 years: RR = 0.33, 95% CI = 0.25 to 0.45) was associated with lower chemoradiation use among stage II/III rectal cancer patients.

CONCLUSION

Our findings demonstrate increased adoption of chemotherapy and radiation therapy for colon and rectal cancer patients and differences in therapy by age, comorbidity, and diagnosis year. Increased receipt of these therapies in the community may further reduce CRC mortality.

Patterns of colorectal cancer care in the United States and Canada: a systematic review

Colorectal cancer is the third most common cancer in the United States and Canada. Given the high incidence and increased survival of colorectal cancer patients, prevalence is increasing over time in both countries. Using MEDLINE, we conducted a systematic review of the literature published between 2000 and 2010 to describe patterns of colorectal cancer care. Specifically we examined data sources used to obtain treatment information and compared patterns of cancer-directed initial care, post-diagnostic surveillance care, and end-of-life care among colorectal cancer patients diagnosed in the United States and Canada. Receipt of initial treatment for colorectal cancer was associated with the anatomical position of the tumor and extent of disease at diagnosis, in accordance with consensus-based guidelines. Overall, care trends were similar between the United States and Canada; however, we observed differences with respect to data sources used to measure treatment receipt. Differences were also present between study populations within country, further limiting direct comparisons. Findings from this review will allow researchers, clinicians, and policy makers to evaluate treatment receipt by patient, clinical, or system characteristics and identify emerging trends over time. Furthermore, comparisons between health-care systems in the United States and Canada can identify disparities in care, allow the evaluation of different models of care, and highlight issues regarding the utility of existing data sources to estimate national patterns of care.

A multigene prognostic assay for selection of adjuvant chemotherapy in patients with T3, stage II colon cancer: impact on quality-adjusted life expectancy and costs

OBJECTIVES

Uncertainty exists regarding appropriate and affordable use of adjuvant chemotherapy in stage II colon cancer (T3, proficient DNA mismatch repair). This study aimed to estimate the effectiveness and costs from a US societal perspective of a multigene recurrence score (RS) assay for patients recently diagnosed with stage II colon cancer (T3, proficient DNA mismatch repair) eligible for adjuvant chemotherapy.

METHODS

RS was compared with guideline-recommended clinicopathological factors (tumor stage, lymph nodes examined, tumor grade, and lymphovascular invasion) by using a state-transition (Markov) lifetime model. Data were obtained from published literature, a randomized controlled trial (QUick And Simple And Reliable) of adjuvant chemotherapy, and rates of chemotherapy use from the National Cooperative Cancer Network Colon/Rectum Cancer Outcomes study. Life-years, quality-adjusted life expectancy, and lifetime costs were examined.

RESULTS

The RS is projected to reduce adjuvant chemotherapy use by 17% compared with current treatment patterns and to increase quality-adjusted life expectancy by an average of 0.035 years. Direct medical costs are expected to decrease by an average of $2971 per patient. The assay was cost saving for all subgroups of patients stratified by clinicopathologic factors. The most influential variables affecting treatment decisions were projected years of life remaining, recurrence score, and patients' disutilities associated with adjuvant chemotherapy.

CONCLUSIONS

Use of the multigene RS to assess recurrence risk after surgery in stage II colon cancer (T3, proficient DNA mismatch repair) may reduce the use of adjuvant chemotherapy without decreasing quality-adjusted life expectancy and be cost saving from a societal perspective. These findings need to be validated in additional cohorts, including studies of clinical practice as assay use diffuses into nonacademic settings.

The clinical significance of lymph node size in colon cancer

To date, the clinical value of lymph node size in colon cancer has been investigated only in a few studies. Only in radiological diagnosis is lymph node size routinely recognized, and nodes ≥10 mm in diameter are considered pathologic. However, the few studies regarding this topic suggest that lymph node size is not a reliable indicator of metastatic disease. Moreover, we hypothesized that increasing lymph node size is associated with favorable outcome. By performing a morphometric study, we investigated the clinical significance of lymph node size in colon cancer in terms of metastatic disease and prognosis. A cohort of 237 cases with excellent lymph node harvest (mean lymph node count: 33±17) was used. The size distribution in node-positive and -negative cases was almost identical. In all, 151 out of the 305 metastases detected (49.5%) were found in lymph nodes with diameters ≤5 mm. Only 25% of lymph nodes >10 mm showed metastases. Minute lymph nodes ≤1 mm were involved only very rarely (2 of 81 cases). In 67% of the cases, the largest positive lymph node was <10 mm. The prognostic relevance of lymph node size was investigated in a subset of 115 stage I/II cases. The occurrence of ≥7 lymph nodes that were >5 mm in diameter was significantly associated with better overall survival. Our data show that lymph node size is not a suitable factor for preoperative lymph node staging. Minute lymph nodes have virtually no role in correct histopathological lymph node staging. Finally, large lymph nodes in stage I/II disease might indicate a favorable outcome.

Long-term survival results of surgery alone versus surgery plus UFT (Uracil and Tegafur)-based adjuvant therapy in patients with stage II colon cancer

BACKGROUND

It is well established that adjuvant chemotherapy with 5-fluouracil and leucovorin (5-FU/LV) improves survival for patients with resected colon cancer; however, the benefits of oral uracil and tegafur (UFT) chemotherapy in these patients are still uncertain.

METHODS

All patients enrolled in this retrospective study with stage II disease who were treated with surgery or surgery plus UFT were examined to determine the overall survival and disease-free interval. Time-to-event by treatment group was examined using Kaplan-Meier estimates and multivariable Cox regression analysis.

RESULTS

There were 456 eligible patients-217 (47.5%) patients had surgery and 239 (52.5%) patients had surgery plus UFT. In patients aged ≧65 years, deeper tumor depth and fewer nodes observed were associated with lower survival. The 5-year survival rate was 84.2% in the surgery group and 89.1% in the surgery plus UFT group (P = 0.006). Treatment with UFT after surgery was associated with improved outcome compared with surgery alone: overall survival (HR = 0.611, P = 0.018) and disease-free survival (HR = 0.590, P = 0.032).

CONCLUSIONS

Oral fluoropyrimidines improve the disease-free rate and the overall survival of patients after resection of stage II colon cancer. These observations support the use of these agents following surgery as it provides a benefit over surgery alone.

Validation study of a quantitative multigene reverse transcriptase-polymerase chain reaction assay for assessment of recurrence risk in patients with stage II colon cancer

PURPOSE

We developed quantitative gene expression assays to assess recurrence risk and benefits from chemotherapy in patients with stage II colon cancer.

PATIENTS AND METHODS

We sought validation by using RNA extracted from fixed paraffin-embedded primary colon tumor blocks from 1,436 patients with stage II colon cancer in the QUASAR (Quick and Simple and Reliable) study of adjuvant fluoropyrimidine chemotherapy versus surgery alone. A recurrence score (RS) and a treatment score (TS) were calculated from gene expression levels of 13 cancer-related genes (n = 7 recurrence genes and n = 6 treatment benefit genes) and from five reference genes with prespecified algorithms. Cox proportional hazards regression models and log-rank methods were used to analyze the relationship between the RS and risk of recurrence in patients treated with surgery alone and between TS and benefits of chemotherapy.

RESULTS

Risk of recurrence was significantly associated with RS (hazard ratio [HR] per interquartile range, 1.38; 95% CI, 1.11 to 1.74; P = .004). Recurrence risks at 3 years were 12%, 18%, and 22% for predefined low, intermediate, and high recurrence risk groups, respectively. T stage (HR, 1.94; P < .001) and mismatch repair (MMR) status (HR, 0.31; P < .001) were the strongest histopathologic prognostic factors. The continuous RS was associated with risk of recurrence (P = .006) beyond these and other covariates. There was no trend for increased benefit from chemotherapy at higher TS (P = .95).

CONCLUSION

The continuous 12-gene RS has been validated in a prospective study for assessment of recurrence risk in patients with stage II colon cancer after surgery and provides prognostic value that complements T stage and MMR. The TS was not predictive of chemotherapy benefit.

The impact of age on quality measure adherence in colon cancer

BACKGROUND

Recently lymph node yield (LNY) has been endorsed as a quality measure of colon cancer resection adequacy. It is unclear whether this measure is relevant to all ages. We hypothesized that total lymph node yield (LNY) is negatively correlated with increasing age and overall survival (OS).

STUDY DESIGN

The Surveillance, Epidemiology and End Results (SEER) database was queried for all nonmetastatic colon cancer patients diagnosed from 1992 to 2004 (n = 101,767), grouped by age (<40, 41 to 45, 46 to 50, and in 5-year increments until 86+ years). Proportions of patients meeting the 12 LNY minimum criterion were determined in each age group and analyzed with multivariate linear regression adjusting for demographics and American Joint Committee on Cancer (AJCC) 6(th) Edition stage. OS comparisons in each age category were based on the guideline of 12 LNY.

RESULTS

Mean LNY decreased with increasing age (18.7 vs 11.4 nodes/patient, youngest vs oldest group, p < 0.001). The proportion of patients meeting the 12 LNY criterion also declined with each incremental age group (61.9% vs 35.2% compliance, youngest vs oldest, p < 0.001). Multivariate regression demonstrated a negative effect of each additional year in age and log (LNY) with coefficient of -0.003 (95% CI -0.003 to -0.002). When stratified by age and nodal yield using the 12 LNY criterion, OS was lower for all age groups in stage II colon cancer with less than 12 LNY, and each age group over 60 years with less than 12 LNY for stage III colon cancer (p < 0.05).

CONCLUSIONS

Every attempt to adhere to proper oncologic principles should be made at the time of colon cancer resection regardless of age. The prognostic significance of the 12 LN minimum criterion should be applied even to elderly colon cancer patients.

Long-term survival results of surgery alone versus surgery plus 5-fluorouracil and leucovorin for stage II and stage III colon cancer: pooled analysis of NSABP C-01 through C-05. A baseline from which to compare modern adjuvant trials

BACKGROUND

The objective of this study is to conduct a pooled analysis of National Surgical Adjuvant Breast and Bowel Project (NSABP) colon trials involving surgery and surgery plus 5-fluorouracil and leucovorin (5-FU/LV) to compare survival and establish a baseline from which to evaluate future studies.

METHODS

All patients enrolled in NSABP adjuvant trials C-01 through C-05 with stage II and III disease who were treated with surgery or with surgery plus 5-FU/LV were examined for overall survival (OS), disease-free survival (DFS), and recurrence-free interval (RFI). Time-to-event by treatment group was examined using adjusted Kaplan-Meier estimates and multivariable Cox regression analysis.

RESULTS

There were 2,966 eligible patients: 693 (23%) surgery and 2,273 (77%) surgery plus 5-FU/LV; 1,255 (42%) stage II and 1,711 (58%) stage III. Age > or =60 years [hazard ratio (HR) = 1.36, P < 0.0001], male gender (HR = 1.20, P = 0.0012), and more nodes positive or fewer nodes examined (P < 0.0001) were associated with worse survival. At 5 years, the adjusted OS was 0.62 [confidence interval (CI) = 0.60-0.63] in the surgery group and 0.76 (CI = 0.74-0.78) in the surgery plus 5-FU/LV group. Treatment with 5-FU/LV was associated with improved outcome compared with surgery: OS (HR = 0.62, P < 0.0001), DFS (HR = 0.66, P < 0.0001) and RFI (HR = 0.64, P < 0.0001). Improved OS with adjuvant treatment was seen in both stage II (HR = 0.58, 95% CI = 0.48-0.71) and stage III disease (HR = 0.65, 95% CI = 0.55-0.75).

CONCLUSIONS

This analysis demonstrates that treatment of colon cancer patients with 5-FU/LV following surgery provides benefit over surgery alone and can provide anticipated survival outcomes with which to compare modern adjuvant trials.

Stage II/III rectal cancer with intermediate response to preoperative radiochemotherapy: do we have indications for individual risk stratification?

Background

Response to preoperative radiochemotherapy (RCT) in patients with locally advanced rectal cancer is very heterogeneous. Pathologic complete response (pCR) is accompanied by a favorable outcome. However, most patients show incomplete response. The aim of this investigation was to find indications for risk stratification in the group of intermediate responders to RCT.

Methods

From a prospective database of 496 patients with rectal adenocarcinoma, 107 patients with stage II/III cancers and intermediate response to preoperative 5-FU based RCT (ypT2/3 and TRG 2/3), treated within the German Rectal Cancer Trials were studied. Surgical treatment comprised curative (R0) total mesorectal excision (TME) in all cases. In 95 patients available for statistical analyses, residual transmural infiltration of the mesorectal compartment, nodal involvement and histolologic tumor grading were investigated for their prognostic impact on disease-free (DFS) and overall survival (OS).

Results

Residual tumor transgression into the mesorectal compartment (ypT3) did not influence DFS and OS rates (p = 0.619, p = 0.602, respectively). Nodal involvement after preoperative RCT (ypN1/2) turned out to be a valid prognostic factor with decreased DFS and OS (p = 0.0463, p = 0.0236, respectively). Persistent tumor infiltration of the mesorectum (ypT3) and histologic tumor grading of residual tumor cell clusters were strongly correlated with lymph node metastases after neoadjuvant treatment (p < 0.001).

Conclusions

Advanced transmural tumor invasion after RCT does not affect prognosis when curative (R0) resection is achievable. Residual nodal status is the most important predictor of individual outcome in intermediate responders to preoperative RCT. Furthermore, ypT stage and tumor grading turn out to be additional auxiliary factors. Future clinical trials for risk-adapted adjuvant therapy should be based on a synopsis of clinicopathologic parameters.