Colon Cancer Staging in Vulnerable Older Adults: Adherence to National Guidelines and Impact on Survival

Research Article

Ann Hematol Oncol. 2014;1(3): 1012.

Colon Cancer Staging in Vulnerable Older Adults: Adherence to National Guidelines and Impact on Survival

Leal TB1,2, Holden T2, Cavalcante L2, Allen GO3, Schumacher JR3, Smith MA3, Weiss JM1,5, Neuman HB4 and LoConte NK1,2,3*

1University of Wisconsin Carbone Cancer Center, USA

2Department of Medicine of Hematology/Oncology, University of Wisconsin Section, USA

3University of Wisconsin Health Innovation Program, USA

4Department of Surgery, University of Wisconsin, USA

5Department of Medicine, University of Wisconsin, USA

*Corresponding author: LoConte NK, Department of Medicine and Carbone Cancer Center, University of Wisconsin, 600 Highland Ave, CSC K4/530, Madison, WI 53792, USA

Received: October 31, 2014; Accepted: November 26, 2014; Published: November 28, 2014


Background: There is concern that elders are not adequately evaluated prior to colon cancer surgery. We sought to determine adherence with ACOVE-3 (Assessing Care of Vulnerable Elders) quality indicators for pre-operative staging prior to colectomy for colon cancer utilizing the Surveillance, Epidemiology and End Results (SEER)-Medicare linked database (1992-2005).

Methods: We determined the proportion of patients aged 75 and older who had preoperative staging prior to colectomy for colon adenocarcinoma. Preoperative staging was defined as abdominopelvic computed tomography or magnetic resonance imaging scan (SCAN) and colonoscopy or flexible sigmoidoscopy (SCOPE). Multivariate logistic regression identified predictors of adherence. Odds ratios were adjusted for comorbidity, socioeconomic status, and disease severity. The association of adherence to ACOVE-3 and survival was quantified.

Results: Of the 37,862 patients, the majority were 75-84 years, 28% of the patients were >85 years. Regarding preoperative staging in the 6-month interval prior to surgical resection, 8% had neither SCAN nor SCOPE, 6% had only SCAN, 43% had only SCOPE, and 43% had both SCAN and SCOPE. Compared to patients who were not staged, those evaluated with either SCOPE alone or SCAN plus SCOPE had lower odds of 3-year mortality. Patients who were staged with SCAN alone had an increased odds of death compared to those who had neither SCAN or SCOPE.

Conclusion: These data demonstrate that the majority of vulnerable elders with colon cancer did not receive appropriate preoperative staging prior to resection. The findings also confirm that adherence to ACOVE-3 guidelines is associated with improved long-term survival.

Keywords: ACOVE-3; Colon cancer; Quality indicators; Vulnerable elders; SEER-Medicare


Colorectal cancer remains the second leading cause of cancerrelated death in the United States, despite the advances in the multidisciplinary treatment. Colon cancer is more common as one age, with age being one of the predominant risk factors for its development. By 2030, the segment of the population aged 80 and older is projected to reach 19.5 million and by 2050 this figure will reach 34 million or 8% of the total population. Thus, colon cancer, a disease of the elderly, is becoming an ever more significant population health concern [1]. The last two decades have seen an improvement in colon cancer survival, which has been attributed to better screening, staging, surgery, and systemic therapy [2]. However, significant disparities in colon cancer outcomes persist, especially for older adults. A study based on the California Cancer Registry demonstrated worse outcomes for octogenarians and nonagenarians with colorectal cancer in terms of morbidity, mortality, and readmission rates compared with younger patients [3]. There is limited information available about measuring the quality of medical care that is targeted to the needs of older patients receiving treatment for colon cancer. Measuring the quality of medical care for ill older adults is complex, because they tend to have multiple medical comorbidities, and there is substantial variation in goals of care [4]. The Assessing Care of Vulnerable Elders (ACOVE) project was created in 1998 to develop and apply quality indicators for the medical care of vulnerable older persons [4]. The project focuses on the 20-40% of community-dwelling older people who are at moderate to high risk of death or decline in Instrumental Activities of Daily Living (IADL) or Activities of Daily Living (ADL) over 2 years [5]. This group uses a disproportionate number of health care resources and is most susceptible to the effects of poor quality care. The ACOVE quality indicators are based on the Donabedian quality model [6], which focuses on processes of care. In 2007, the third phase of the project, ACOVE-3, introduced new indicators for a number of conditions including colon cancer. ACOVE-3 included two recommendations related to preoperative staging of older adults with colon cancer: 1) cross-sectional imaging of the abdomen and pelvis and 2) endoscopic evaluation of the entire colon [7]. Improved preoperative colon cancer staging in older adults has the potential to limit unnecessary surgery for those with metastatic cancer and improve outcomes for individuals with potentially curable disease. However, little is known about the frequency and patterns of colon cancer staging in vulnerable older adults. The association between adherences to ACOVE-3 proposed staging guidelines and long-term survival has not been studied using population-based data. In this study we addressed these knowledge gaps by analyzing the national Surveillance, Epidemiology and End Results (SEER)-Medicare linked database to describe patterns of colon cancer staging in older adults and their relationship to survival.


This study was prospectively reviewed by the University of Wisconsin-Madison Health Sciences Institutional Review Board and determined to be exempt under Code of Federal Regulations Title 45 Part 46.101(b).

Data sources

We obtained data from the SEER-Medicare linked database for patients diagnosed with colon cancer between 1992 and 2005. SEER-Medicare database combines Medicare administrative claims data and detailed clinical tumor registry data. It is one of the few population-based data resources available for the analysis of cancer care quality [8,9]. The SEER program of cancer registries collects information about patient demographics, tumor characteristics, first course of treatment, and survival for persons newly diagnosed with cancer. For people who are Medicare eligible, the SEER-Medicare database includes information on covered health care services, including hospital, physician, outpatient, home health, and hospice claims. The linkage of persons in the SEER database to their Medicare claims is performed by the National Cancer Institute (NCI) and the Centers for Medicare and Medicaid Services (CMS), with a linkage success rate of 93% [8,10]. SEER registries from 1992 to 2002 contain incident cancer diagnoses in the following cities, states, and regions: Los Angeles, San Francisco-Oakland, San Jose-Monterey, Greater California, Connecticut, Detroit, Atlanta, Rural Georgia, Hawaii, Iowa, Kentucky, Louisiana, New Jersey, New Mexico, Seattle-Puget Sound, and Utah. In 2000, SEER regions included approximately 26% of the United States population [8].


All Medicare-enrolled patients aged 75 years and older diagnosed with primary colon adenocarcinoma in a SEER area from 1992 to 2005 were evaluated for inclusion in the study. Included patients had a diagnosis of American Joint Committee on Cancer (AJCC) stage I, II, III, or unstaged colon (SEER cancer site codes 18.0 -18.9, and 19.9) adenocarcinoma (SEER histology codes 8140-47, 8210-11, 8220-21, 8260-63, 8480-81, and 8490). Patients with mucinous cystadenocarcinoma (histology code 8470) were excluded because the natural history of this disease, which occurs in the appendix and is associated with pseudomyxoma peritonei, is different than other histologic subtypes of colon adenocarcinoma [11]. Patients with rectal cancer were also excluded because the surgical treatment of rectal canceris different from that of colon cancer, is often more technically challenging, and may be associated with a higher rate of complications. Patients were required to be continuously enrolled in parts A and B of fee-for-service Medicare for the 12 months preceding cancer diagnosis to ascertain comorbidity and for an additional 6 months after surgical discharge or until death, whichever came first, to enable tracking procedures. Patients enrolled in health maintenance organizations were excluded as their billing information could not be obtained from this database. All included patients underwent primary tumor resection, corresponding to International Classification of Diseases, ninth revision, Clinical Modification (ICD- 9-CM) procedure codes 45.7X (partial excision of large intestine) and 45.8X (total intra-abdominal colectomy). Patients were excluded if they did not undergo tumor resection within 6 months of diagnosis as it was felt that these patients either had rapidly progressive disease or comorbidities which dictated their ability to tolerate surgery. Patients were also excluded if they were diagnosed with another malignancy 1 year before or after the date of colon cancer diagnosis as this other cancer diagnosis was thought to possibly influence the treatments offered for their colon cancer. Patients were also excluded if their first diagnosis of colon cancer was made after death (i.e., on autopsy).

Outcome variable

The primary outcome of interest was preoperative staging in accordance to ACOVE-3 quality indicators. We defined adherence to the cross-sectional imaging indicator (SCAN) as receipt of an abdominopelvic computed tomography (CT: CPT-4 codes 74150, 74160, 74170, 72192, 72193, 72194) [12] or magnetic resonance imaging (MRI: CPT-4 codes 74181, 74185, 72196, 72198) [12] within 6 months prior to surgical resection. The ACOVE-3 indicator related to preoperative endoscopic evaluation of the colon (SCOPE) was defined as either colonoscopy (HCPCS codes G0105, G0121, 44388- 44389, 45378, 45380, 45382-45385 and ICD-9-CM 45.23, 45.25, 45.41-45.43, 48.36) [13] or flexible sigmoidoscopy (HCPCS codes G0104, 45330-45331, 45333, and 45338-45339, and ICD-9-CM 45.22, 45.24, 48.22, and 48.24) [13], within 6 months prior to surgery. Adherence to ACOVE-3 staging recommendations was categorized as no staging, SCAN only, SCOPE only, or both SCAN and SCOPE for each patient in the study. A secondary outcome measure, 3-year mortality, was created based on dates of death recorded in the SEER Patient Entitlement and Diagnosis Summary File (PEDSF) according to Social Security Administration data.

Predictor variables

Information on date of birth, gender, marital status, and race/ ethnicity was obtained from the SEER database. Census tract level median household income and median level of education were obtained from the PEDSF and used as proxies for patient socioeconomic status. Geographic region represented by SEER registry and rural/urban residence based on Rural/Urban Commuting Area Codes were also obtained from the PEDSF. To measure comorbidity, we used CMS Hierarchical Condition Categories (HCCs) [14] based on outpatient and inpatient diagnoses from the 12 months prior to colon cancer diagnosis. We also recorded the number of hospitalizations for each individual in the year prior to cancer diagnosis. In addition to the patient-related variables described above, we measured a variety of disease-related variables. American Joint Committee on Cancer (AJCC) stage and tumor grade was obtained from the SEER database. To allow adjustment for acuity of illness, we identified patients who presented with intestinal obstruction or perforation (ICD-9-CM diagnosis codes 560.89 and 560.9, respectively), and those who were emergently admitted prior to colectomy.

Statistical analysis

We determined adherence to preoperative SCAN and SCOPE prior to colectomy for colon cancer. We compared the frequency of patient-related (age, gender, race/ethnicity, census-tract based income and education, SEER registry, urban/rural residence, hospitalization in the year prior to colon cancer surgery, HCC comorbidity score) and disease-related (stage, grade, obstruction, perforation, emergent admission) variables in patients who did and did not have preoperative staging. We used logistic regression to analyze these data and determine adjusted ORs and 95% Confidence Intervals (CIs) of adherence to preoperative staging for different predictors, controlling for the other patient- and disease- related factors. Logistic regression was also used to quantify the association between staging patterns and 3-year mortality. Analyses were performed using Stata 13.1 software (Statacorp, College Station, Texas). All tests of significance were at the P < 0.05 level, and P values were 2-tailed.


Patient characteristics

A total of 37,862 individuals met the inclusion criteria for the study and characteristics are summarized in Table 1. Of the 37,862 patients identified, 28% of the patients were >85 years, and the remainder were 75-84 years. Most patients were female (62%), Caucasian (87%), married or widowed (86%) and resided in a major metropolitan area 56% (see Table 1). The most frequent stage at diagnosis was stage II (44%), followed by stage III (29%), stage I (24%) and unstaged (4%). The majority of tumors was located in the right-side of the colon (58%) and had moderately-differentiated adenocarcinoma histology (66%). A significant proportion of admissions were coded as nonelective (60%) and the frequency of obstruction and perforation at presentation were 4% and 2%, respectively.