Survival trends for left and right sided colon cancer using population-based SEER database: A forty-five-year analysis from 1975 to 2019

BACKGROUND

Survival differences between left-sided colon cancer (LSCC) and right-sided colon cancer (RSCC) has been previously reported with mixed results, with various study periods not accounting for other causes of mortality.

PURPOSE

We sought to assess the trends in colon cancer cause- specific survival (CSS) and overall survival (OS) based on sidedness.

METHOD

Fine-Gray competing risk and Cox models were used to analyze Surveillance, Epidemiology, and End Results (SEER) population-based cohort from 1975 to 2019. Various interval periods were identified based on the timeline of clinical adoption of modern chemotherapy (1975-1989, interval period A; 1990-2004, B; and 2005-2019, C).

RESULTS

Of the 227,637 patients, 50.1% were female and 46.2% were RSCC. RSCC was more common for African Americans (51.5%), older patients (age ≥65; 51.4%), females (50.4%), while LSCC was more common among Whites (53.1%; p < 0.001), younger patients (age 18-49, 64.6%; 50-64, 62.3%; p < 0.001), males (58.1%; p < 0.001). The Median CSS for LSCC and RCC were 19.3 and 16.7 years respectively for interval period A (1975-1989). Median CSS for interval periods B and C were not reached (more than half of the cohort was still living at the end of the follow-up period). Adjusted CSS was superior for LSCC versus RSCC for the most recent interval period C (HR 0.89; 0.86-0.92; p < 0.001). LSCC consistently showed superior OS for all study periods. Stage stratification showed worse CSS for localized and regional LSCC in the earlier study periods, but the risk attenuated over time. However, left sided distant disease had superior CSS per stage for all interval periods. OS was better for LSCC irrespective of stage, with gradual improvement over time.

CONCLUSION

LSCC was associated with superior survival compared to right sided tumors. With the adoption of modern chemotherapy regimens, prognosis between LSCC and RSCC became more divergent in favor of LSCC. Colon cancer clinical trials should strongly consider tumor sidedness as an enrollment factor.

Poorer Survival in Patients with Cecum Cancer Compared with Sigmoid Colon Cancer

Background and Objectives: An increasing number of studies have shown the influence of primary tumor location of colon cancer on prognosis, but the prognostic difference between colon cancers at different locations remains controversial. After comparing the prognostic differences between left-sided and right-sided colon cancer, the study subdivided left-sided and right-sided colon cancer into three parts, respectively, and explored which parts had the most significant prognostic differences, with the aim to further analyze the prognostic significance of primary locations of colon cancer. Materials and Methods: Clinicopathological data of patients with colon cancer who underwent radical surgery from the Surveillance, Epidemiology, and End Results Program database were analyzed. The data was divided into two groups (2004−2009 and 2010−2015) based on time intervals. Two tumor locations with the most significant survival difference were explored by using Cox regression analyses. The prognostic difference of the two locations was further verified in survival analyses after propensity score matching. Results: Patients with right-sided colon cancer had worse cancer-specific and overall survival compared to left-sided colon cancer. Survival difference between cecum cancer and sigmoid colon cancer was found to be the most significant among six tumor locations in both 2004−2009 and 2010−2015 time periods. After propensity score matching, multivariate analyses showed that cecum cancer was an independent unfavorable factor for cancer specific survival (HR [95% CI]: 1.11 [1.04−1.17], p = 0.001 for 2004−2009; HR [95% CI]: 1.23 [1.13−1.33], p < 0.001 for 2010−2015) and overall survival (HR [95% CI]: 1.09 [1.04−1.14], p < 0.001 for 2004−2009; HR [95% CI]: 1.09 [1.04−1.14], p < 0.001 for 2010−2015) compared to sigmoid colon cancer. Conclusions: The study indicates the prognosis of cecum cancer is worse than that of sigmoid colon. The current dichotomy model (right-sided vs. left-sided colon) may be inappropriate for the study of colon cancer.

Recent estimates and predictions of 5-year survival rate in patients with pancreatic cancer: A model-based period analysis

Background

The 5-year survival rate for pancreatic cancer (PC) is incredibly low, resulting in this often being a fatal disease. Timely and accurate assessment of the survival rate and prognosis of patients with PC is of great significance for the development of new programs for prevention, monitoring, and treatment.

Methods

Period analysis and further stratified analysis were used to determine the 5-year relative survival rate (RSR) of patients with PC from 2002 to 2016 using the Surveillance, Epidemiology, and End Results (SEER) project database of the National Cancer Institute. Based on this, a generalized linear model was created to predict the survival rate of patients from 2017 to 2021.

Result

During 2002-2016, the 5-year RSR of patients with PC increased from 7.9 to 23.7%. The generalized linear model predicted that the survival rate had increased to 33.9% during 2017-2021, and hence, it was still unacceptably low. The survival rate of patients aged ≥75 years at diagnosis was the lowest among all age groups and was predicted to be only 21.4% during 2017-2021. Notably, the survival rate of patients with differentiation grade III at diagnosis remains particularly low at 7.6%.

Conclusion

The survival rates of patients with PC, although slightly improved, remain extremely low. Timely assessment of the trend of survival rate changes in patients with PC further improves the prognosis of tumor patients and provides data support for relevant medical works to formulate effective tumor prevention and control policies.

Survival Trends of Right- and Left-Sided Colon Cancer across Four Decades: A Norwegian Population-Based Study

BACKGROUND

Patients with right-sided colon cancer (RCC) and left-sided colon cancer (LCC) differ clinically and molecularly. The main objective was to investigate stage-stratified survival and recurrence of RCC and LCC across four 10-year periods.

METHODS

Patients diagnosed from 1977 to 2016 with colon adenocarcinoma were included from the Cancer Registry of Norway. Primary tumor location (PTL) was defined as RCC if proximal and LCC if distal to the splenic flexure. Multivariable regressions were used to estimate HRs for overall survival (OS), recurrence-free survival (RFS), survival after recurrence (SAR), and excess HRs (eHR) for relative survival (RS).

RESULTS

72,224 patients were eligible for analyses [55.1% (n = 39,769/72,224) had RCC]. In 1977 to 1986, there was no difference between LCC and RCC in OS [HR, 1.01; 95% confidence interval (CI), 0.97-1.06; P = 0.581] or RS (eHR, 0.96; 95% CI, 0.90-1.02; P = 0.179). In 2007 to 2016, LCC had significantly better OS (HR, 0.84; 95% CI, 0.80-0.87; P < 0.001) and RS (eHR, 0.76; 95% CI, 0.72-0.81; P < 0.001) compared with RCC. The gradually diverging and significantly favorable prognosis for LCC was evident for distant disease across all time periods and for regional disease from 2007 onward. There was no difference in RFS between LCC and RCC in patients less than 75 years during 2007 to 2016 (HR, 0.99; 95% CI, 0.91-1.08; P = 0.819); however, SAR was significantly better for LCC (HR, 0.61; 95% CI, 0.53-0.71; P < 0.001).

CONCLUSIONS

A gradually diverging and increasingly favorable prognosis was observed for patients with LCC with advanced disease over the past four decades.

IMPACT

Current PTL survival disparities stress the need for further exploring targetable molecular subgroups across and within different PTLs to further improve patient outcomes.

Time-varying prognostic effects of primary tumor sidedness and grade after curative liver resection for colorectal liver metastases

BACKGROUND

The veracity of the proportional hazards (PH) requirement is rarely scrutinized in most areas of cancer research, although fulfilment of this assumption underpins widely-used Cox survival models. We sought to critically appraise the existence of prognostic factors with time-dependent effects and to characterize their impact on survival among CLM patients.

METHODS

Consecutive patients who underwent liver resection with curative intent for CLM at the Singapore General Hospital were identified from a prospectively-maintained database. We evaluated PH of 55 candidate variables, and parameters which departed significantly from proportionality were included in Cox models that incorporated an interaction term to account for time-dependent effects. As sensitivity analyses, we fitted Weibull mixture 'cure' models to handle long plateaus in the tails of survival curves, and also analyzed the restricted mean survival time.

RESULTS

318 consecutive patients who underwent curative liver resection for CLM between Jan 2000 and Nov 2016 were included in this analysis. Hazard ratios for tumor grade (poorly-versus well- and moderately-differentiated) were found to decrease from 3.135 (95% CI: 1.637-6.003) at 12 months to 2.048 (95% CI: 1.038-4.042) after 24 months, and ceased to be significant at 26 months. Compared to left-sided tumors, a right-sided tumor location was found to portend worse prognosis for the first 10 months after resection but subsequently confer a survival benefit due to a crossing of survival curves. Corroborating this observation, long-term cure fractions were estimated to be 25.5% (95% CI: 17.4%-33.6%) and 34.2% (95% CI: 17.4%-50.9%) among patients with left-sided and right-sided primary disease respectively.

CONCLUSION

Primary tumor sidedness and grade appear to exert time-varying prognostic effects in CLM patients undergoing curative liver resection.

Real-world Data for High-risk Stage II Colorectal Cancer - The Role of Tumor Side in the Adjuvant Setting

BACKGROUND

The impact of sidedness in the high-risk stage II colorectal cancer (CRC) setting is uncertain. Although controversial, available data suggest a possible modest benefit of adjuvant chemotherapy (CT) in the adjuvant scenario. The aim of this study is to analyze the overall survival (OS) and recurrence-free survival (RFS) according to the tumor side.

PATIENTS AND METHODS

In this single-center retrospective cohort, we analyzed patients treated between January 2011 and December 2018. We evaluated OS and RFS of high-risk patients according to the tumor side and considering adjuvant CT exposure and clinical and molecular features.

RESULTS

A total of 1047 patients with stage II CRC were evaluated. Of these, 540 had high-risk criteria and microsatellite stability (MSS) or unknown status. One hundred fifty-seven (29%) patients had right-sided tumors, and 352 (65.2%) had left-sided tumors. Most patients received adjuvant CT, and the majority of them had T3 stage tumors, ≥ 12 lymph node resection, left tumor, MSS, and moderate differentiation. OS did not differ according to tumor side (5-year OS rates: 81.9% for right-sided tumors vs. 83% for left-sided tumors; hazard ratio, 0.91; 95% confidence interval, 0.55-1.53; P = .744). Adjuvant CT was associated with a superior RFS and OS, with 5-year OS rates of 87.7% versus 76.1% in the no-adjuvant group (hazard ratio, 0.46; 95% CI, 0.28-0.73; P = .001).

CONCLUSION

The tumor side did not influence the outcomes in this study. Adjuvant CT was associated with improved RFS and OS in patients with high-risk stage II CRC, with a total gain of 11.6% in 5-year OS.

Early-onset colorectal cancer: more than one side to the story

Aim: To determine the impact of tumor sidedness on all-cause mortality for early- (age 18–49 years) and older-onset (age ≥50 years) colorectal cancer (CRC). Materials & methods: We conducted a retrospective study of 650,382 patients diagnosed with CRC between 2000 and 2016. We examined the associations of age, tumor sidedness (right colon, left colon and rectum) and all-cause mortality. Results: For early-onset CRC (n = 66,186), mortality was highest in the youngest age group (18–29 years), driven by left-sided colon cancers (vs 50–59 years, hazard ratio: 1.18; 95% CI: 1.03–1.34). 5-year risk of death among 18–29-year-olds with left-sided colon cancer (0.42, 95% CI: 0.38, 0.46) was higher than all other age groups. Conclusion: Left-sided colon cancers are enriched in younger adults and may be disproportionately fatal.

Effect of primary colorectal cancer tumor location on survival after pulmonary metastasectomy

OBJECTIVES

Although colorectal cancer bowel segment location has been shown to independently predict the outcomes in early stage disease, it has not been previously studied in the setting of pulmonary metastases. We sought to determine whether colorectal cancer location affects survival after pulmonary metastasectomy.

METHODS

Patients who had undergone pulmonary metastasectomy for colorectal cancer at a single institution from 2011 to 2018 were reviewed. Univariable and multivariable Cox regression analyses were performed to identify predictors of overall survival and disease-free survival. The Kaplan-Meier survival method was used to determine differences between groups.

RESULTS

A total of 194 patients were evaluated. The median follow-up, survival time, and 5-year survival rate were 36.8 months, 75.8 months, and 57%, respectively, and 122 patients (63%) had experienced disease recurrence at any location. On univariable analysis, age, primary tumor location, pulmonary nodule size, ≥3 pulmonary nodules, and intrathoracic nodal disease were associated with overall survival. On multivariable analysis, patients with left-sided tumors experienced a survival benefit (hazard ratio, 0.31; P = .036). Kaplan-Meier analysis revealed a median survival time of 90 months (95% confidence interval, 82 months to not reached) compared with 55 months (95% confidence interval, 49 months to not reached) for patients with left-sided and rectal tumors, respectively, after metastasectomy (P = .078). Location was not associated with disease-free survival on Cox multivariable regression.

CONCLUSIONS

We found that left-sided colorectal cancer is associated with prolonged survival after pulmonary metastasectomy. Future investigations are required to determine the validity of such findings, including the effect of location in the prognostication for patients who are candidates for pulmonary metastasectomy.

Two sides to colon cancer: mice mimic human anatomical region disparity in colon cancer development and progression

Aim:

Strong evidence reveals important differences between cancers in the proximal vs. distal colon. Animal models of metastatic colon cancer are available but with varying degrees of reproducibility and several important limitations. We explored whether there were regional differences in the location of murine colon cancers and assessed the utility of murine models to explore the biological basis for such differences.

Methods:

We re-analyzed data from our previous studies to assess the regional distribution of murine colon cancer. In survival surgery experiments, we injected HT-29 human colon cancer cells into the wall of the cecum or distal colon of Nu(NCr)-Foxn1^nu or NOD.Cg-Prkdc^scidIl2rg^Tim1Wji/SzJ mice and compared the development of primary tumors and metastases.

Results:

Within 7–17 weeks after intramural cecal injection of HT-29 cells, eight mice failed to develop solid primary tumors or metastases. In contrast, within four weeks after cell injection into the distal colon, 13 mice developed metastases - 12 mice developed subcutaneous metastases; of these, four developed liver metastases and one developed both liver and lung metastases. One mouse developed liver metastases only. Histological examination confirmed these lesions were adenocarcinomas.

Conclusion:

Our findings reveal the preferential growth of murine colon neoplasia and invasive human orthotopic xenografts in the distal mouse colon. The new approach of injecting cells into the distal colon wall results in a pattern of colon cancer development that closely mimics the progression of metastatic colon cancer in humans. This novel model of colon neoplasia has great potential for exploring anatomical differences in colon cancer and testing novel therapeutics.