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10.1245/ASO.2003.03.034
Annals of Surgical Oncology 10:1112-1117 (2003)
© 2003 Society of Surgical Oncology
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ORIGINAL ARTICLES

Workload Projections for Surgical Oncology: Will We Need More Surgeons?

David A. Etzioni, MD, MSHS, Jerome H. Liu, MD, MSHS, Melinda A. Maggard, MD, Jessica B. O’Connell, MD and Clifford Y. Ko, MD, MS, MSHS

From the Department of Surgery (DAE, JHL, MAM, JBO, CYK), David Geffen School of Medicine at the University of California, Los Angeles; and Department of Surgery (JHL, MAM, JBO, CYK), VA Greater Los Angeles Healthcare System, Los Angeles, California.

Correspondence: Address correspondence and reprint requests to: David A. Etzioni, MD, David Geffen School of Medicine at the University of California, Los Angeles, Department of Surgery, 1015 Ninth Street, Apt. 106, Santa Monica, CA 90403; Fax: 310-794-3288; E-mail: detzioni{at}mednet.ucla.edu


   ABSTRACT
TOP
 ABSTRACT
INTRODUCTION
 METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 
Background: Over the next two decades, the US population will experience dramatic growth in the number and relative proportion of older individuals. The aim of this study was to quantify the effect of these changes on the demand for oncological procedures.

Methods: The 2000 Nationwide Inpatient Sample and the 1996 National Survey of Ambulatory Surgery were used to compute age-specific incidence rates for oncological procedures of the breast, colon, rectum, stomach, pancreas, and esophagus. Procedure rates were combined with census projections for 2010 and 2020 to estimate the future utilization of each procedure.

Results: By 2020, the number of patients undergoing oncological procedures is projected to increase by 24% to 51%. The bulk of growth in procedures is derived from outpatient procedures, but significant growth will also be seen in inpatient procedures.

Conclusions: The aging of the population will generate an enormous growth in demand for oncological procedures. If a shortage of surgeons performing these procedures does occur, the result will inevitably be decreased access to care. To prevent this from happening, the ability of surgeons to cope with an increased burden of work needs to be critically evaluated and improved.

Key Words: Workload • Workforce • Aging • Projection • Surgery


   INTRODUCTION
TOP
 ABSTRACT
 INTRODUCTION
METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 
Over the next two decades, the US population will experience dramatic growth in the number and proportion of older individuals. These changes are the result of several important trends. First, the life expectancy for individuals in the United States has increased significantly, from 66.7 years for individuals born in 1946 to 76.1 years for those born in 1996.1 The second trend is the aging of the "baby boomer" population. The baby boomers, generally defined as those born between 1946 and 1964, will begin to turn 65 in the year 2011. These two trends are the underlying cause of the aging population. The third important trend is the expansion of the US population. Between 1990 and 2000, the US population grew by 32.7 million people (13.2%), the largest absolute increase of any decade in the country’s history.2

The expanding and aging population will have a significant effect on all segments of the US health-care system. Older individuals use more health-care resources than their younger counterparts. The National Hospital Discharge Survey reported that in 1999, patients aged >=65 years comprised 12% of the population but constituted 40% of hospital discharges and 48% of days of inpatient care.3 These statistics point to the disproportionately high rate of utilization of medical and surgical services by older patients. The specific demand of older patients for surgical services, however, has received little attention.

The demand for oncological procedures is derived mainly from older patients. As the population base of older individuals in the United States increases, the demand for these procedures will certainly increase. The specific focus of this study was to quantify the effect of changes in the US population on the demand for oncological procedures. To accomplish this goal, we constructed an epidemiological model of the age-specific demand for surgical procedures based on nationally representative data. Age-specific rates for oncological procedures were combined with census forecasts to predict future changes in the numbers of procedures performed within the United States.


   METHODS
TOP
 ABSTRACT
 INTRODUCTION
 METHODS
RESULTS
 DISCUSSION
 REFERENCES
 
Data Sources
Nationally representative data regarding inpatient procedures from the year 2000 were obtained from the Nationwide Inpatient Sample (NIS). The NIS is maintained by the Agency for Healthcare Research and Quality as part of its Healthcare Cost and Utilization Project. In 2000, the Agency for Healthcare Research and Quality sampled >7 million discharges from hospitals in 28 states to create the NIS. These discharges represent approximately 20% of the total domestic hospitalizations each year. The NIS sampling scheme is designed to be representative of hospitalizations at a national level. Each discharge is weighted to allow an estimation of nationwide rates of surgery based on the 20% sample. Within the NIS, inpatient procedures and diagnoses are reported by using International Classification of Diseases (9th revision) coding schemes.

Data regarding outpatient procedures were obtained from the 1996 National Survey of Ambulatory Surgery (NSAS). The NSAS was conducted only during a 3-year period, from 1994 to 1996. The 1996 NSAS therefore represents the most current nationally representative data regarding outpatient surgical procedures. Its sample size (n = 125,000 per year) is substantially smaller than that of the NIS and, therefore, permits analysis of only the most commonly performed procedures. Each outpatient procedure and pertinent diagnoses are listed with International Classification of Diseases (9th revision) procedure and diagnosis codes. Data from the 1996 NSAS were specifically used to project changes in the demand for outpatient procedures for the diagnosis and treatment of breast cancer. Census data for 2000 and population projections for 2010 and 2020 were obtained through the US Census Bureau.

Procedure Inclusion Criteria
Specific criteria were used to identify surgical procedures for oncological conditions. For all procedures except breast procedures, inclusion was based on both procedural and diagnostic criteria. For example, a colon resection procedure needed to be coded as a colon resection and be associated with a diagnosis of colon cancer to be included.

On the basis of the assumption that virtually all inpatient breast procedures (mastectomies) were performed for neoplastic conditions, only a procedural criterion was used. Outpatient breast procedures (diagnostic and excision procedures) were also identified solely on the basis of procedural criteria, because the diagnosis associated with these procedures may be unknown at the time of surgery. The criteria used are listed in Table 1.


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  		TABLE 1. Criteria for inclusion
 
Computation of Incidence Rates
Incidence rates for each surgical procedure were calculated within nine specific age categories (<15, 15–24, 25–34, 35–44, 45–54, 55–64, 65–74, 75–84, and >=85 years). Each incidence rate was computed by dividing the number of procedures performed within a specific age group by the population within that age group. All incidence rates are reported as the number of procedures per 10,000 individuals per year. Incidence rates based on a sampled quantity of <=10 observations were excluded from analysis.

Projection Method
The calculated age-specific incidence rates from the NIS 2000 and the NSAS 1996 were used as the basis for projecting future changes in procedure volume. The numbers of procedures that will be performed in 2010 and 2020 were calculated by multiplying the incidence rate (within each of the nine age categories) by the census projections (within the relevant age category). This method assumes that procedural rates will remain unchanged over time.

The most current nationally representative data regarding outpatient procedures are from the 1996 NSAS. To estimate outpatient procedures in the year 2000, age-specific incidence rates from 1996 were applied to the actual US population in the year 2000. Data regarding the outpatient procedure volume in the year 2000, therefore, represent an estimate based on historical incidence rates.


   RESULTS
TOP
 ABSTRACT
 INTRODUCTION
 METHODS
 RESULTS
DISCUSSION
 REFERENCES
 
Analysis of Census Projections
Between 2000 and 2020, the US population is forecasted to increase in size by 17%. Population growth will be disproportionately higher in older age groups (Figs. 1 and 2Go). The number of individuals >=55 years will increase more rapidly than the overall population (Fig. 1). Growth will be particularly dramatic for those aged 55 to 64 (74% increase) and those aged 65 to 74 (73% increase). In contrast, the number of younger individuals will grow at substantially lower rates (Fig. 2). Those <=35 years of age will increase by 14% to 16%, and the number of individuals aged 35 to 44 years will actually decrease by 11%.



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  		FIG. 1. US population <55 years old: 2000 to 2020.

 


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  		FIG. 2. US population >=55 years old: 2000 to 2020.

 
Demographic Characteristics of Patients
In the year 2000, a total of 229,200 inpatient procedures and 757,500 outpatient procedures were performed (Table 2). The two classes of outpatient breast procedures (diagnostic procedures and excisions) were performed with approximately equal frequency. Colon resections and mastectomies were the most common inpatient procedures. A relatively lower number of pancreatic, rectal, and gastric resections were performed in 2000.


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  		TABLE 2. Profile of patients undergoing outpatient and inpatient oncological procedures (2000)
 
For each of the inpatient procedures, the vast majority of patients were >=55 years old. The average ages of patients undergoing these procedures were similar, varying from 61.7 years (mastectomy) to 70.7 years (colon resection). A significant percentage of operations were performed on patients aged >=75 years old. The average age of patients undergoing outpatient procedures was younger than that of those undergoing inpatient procedures (50.6 years for diagnostic procedures and 52.0 years for excisions).

Age-Specific Incidence Rates
The calculated age-specific incidence rates are listed in Table 3. Each procedure demonstrated a peak in incidence rate in individuals in the seventh to ninth decade of life. For three procedures (mastectomy, rectal resection, and stomach resection), individuals 75 to 84 years old had the highest incidence rates. Those >=85 years old had the highest incidence rates for colon resection. Patients undergoing outpatient breast procedures and inpatient esophageal or pancreatic resections were younger; those aged 65 to 74 years had the highest incidence rates.


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  		TABLE 3. Age-specific incidence ratesa
 
Predicted Demand for Oncological Procedures
Predicted changes in the nationwide utilization of oncological procedures were calculated by combining age-specific incidence rates with census projections (Table 4). The demand for oncological procedures over the next 20 years will increase more rapidly than overall population growth. By 2020, the number of patients undergoing 1 of the 6 inpatient procedures is projected to increase from 229,200 to 327,100, a gain of 42.7%. Outpatient procedures will increase from 757,500 to 949,700, a gain of 25.4%. Forecasted increases are greatest for esophageal resections, with a 51.2% growth by 2020. The numbers of colon, pancreas, rectal, and stomach resections have forecasted increases of 45.1% to 47.4%. Mastectomies have a slightly lower projected growth (36.8%), and outpatient breast procedures will have the lowest rate of increase (25.4%).


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  		TABLE 4. Projected numbers of surgical oncological procedures: 2010 to 2020
 

   DISCUSSION
TOP
 ABSTRACT
 INTRODUCTION
 METHODS
 RESULTS
 DISCUSSION
REFERENCES
 
The next two decades will bring significant increases in the demand for oncological procedures. Individuals in older age groups are more likely than their younger counterparts to undergo each of the oncological procedures we examined. With the continued expansion and aging of the population, the numbers of patients that undergo these procedures will increase dramatically.

Prior efforts to predict physician workforce needs have been at least partially subjective. In 1980, the Graduate Medical Education National Advisory Committee (GMENAC) released their landmark report regarding physician supply and demand. The methods used in generating this report relied on an expert panel’s estimation of the amount of physician work required to care for specific medical problems. Drawing on these estimates, they forecasted the future need for medical services. The GMENAC report suggested that by the year 2000, there would be a significant surplus of physicians.4 The year 2000 has come and gone, and the predicted physician surplus has not occurred. Unfortunately, the GMENAC report is still influencing national policy regarding graduate medical education. In the two decades before the release of this report, the United States saw a rapid expansion in the number of medical students and graduates from medical schools. The number of medical students graduating per year more than doubled, increasing from 7,000 in 1960 to >15,000 in 1980. Since 1980, the number of medical students graduating each year from domestic medical schools has remained remarkably constant. According to statistics from the Association of American Medical Colleges, 15,427 medical students graduated from US medical schools in 1990. By 2000, this figure had remained essentially unchanged. The number of general surgeons graduating per year has also remained remarkably constant, increasing only from 1,028 in 1990 to 1,043 in 2000.

It is difficult to accurately estimate the workforce of surgeons that perform oncological procedures. The procedures analyzed in this study are performed by fellowship-trained surgical oncologists, as well as by general surgeons and subspecialists within general surgery (i.e., colorectal surgeons). In this study, we used data sources that do not designate the specialty of the surgeon performing a procedure, and, therefore, we could not designate portions of workload growth to surgical oncologists versus other types of general surgeons. In earlier work, we projected similar increases in workload for general surgeons, making it unlikely that in the future oncological procedures will shift to underused general surgeons.5 With increasing subspecialization within general surgery,6 it is more likely that surgeons with subspecialty training (i.e., surgical oncologists and colorectal surgeons) will become more responsible for performing oncological procedures.

The model used to generate our projections is based on age-specific incidence rates from recent, nationally representative data regarding inpatient hospitalizations. This approach, however, has two main limitations. First, the data sources used in this study are compiled from a broad range of hospitals in different regions of the country. Although variations in coding practices or other systematic inaccuracies in data processing may have resulted in inaccurate calculation of incidence rates, it is unlikely that such misclassifications would be substantial. A second limitation is the assumption that rates of surgery will remain constant. It is possible that these rates will change in the future as a result of medical innovations or changes in practice patterns. Colon cancer, for example, may see significant reductions in incidence rates as a result of improved use of screening. Some studies have reported recent reductions in population-based incidence rates of colorectal cancer.7,8 This may be partially attributable to increasing rates of colorectal cancer screening in the United States (currently received by 41.0% of men and 37.5% of women).9,10 Only one large-scale randomized trial thus far has demonstrated that colorectal cancer screening can reduce the incidence of the disease, with a cumulative incidence rate of .80.11 Although this study was conducted with annual fecal occult blood testing, it is notable that 38% of the patients who received screening underwent colonoscopy at some point during the study.12 If the proportion of the population that receives screening doubles between 2000 and 2020, the effect on incidence rates of colorectal cancer would likely be approximately 10%. This reduction is minor compared with the 46% to 47% projected increase in the number of procedures for colon and rectal cancer generated by the aging and expanding population.

Will improved technology replace oncological procedures with less-invasive alternatives? The pattern of surgical care provided to patients with oncological conditions has certainly evolved over time. These changes are perhaps most apparent in the care of patients with breast cancer. Breast-conserving therapy is now an acceptable alternative to mastectomy, and stereotactic techniques to diagnose breast cancer are increasingly used. Our projections are based on a snapshot of the pattern of care provided in the year 2000; by the year 2020, the pattern of care will change in unforeseeable ways. We did not attempt to model the possible effect of technological change on rates of surgery. Instead, we consider the projected growth in workload as a sensitivity analysis. If practice patterns and incidence rates of cancer remain unchanged, the utilization of oncological procedures will increase by 24% to 51%. Unless changes of a similar magnitude occur in practice patterns or incidence rates of cancer, the United States will see major growth in the demand for oncological procedures.

There are two main ways in which surgeons may choose to deal with the forthcoming increases in workload. The first option is to train more surgeons to perform these procedures. This is unfortunately quite difficult to achieve. Recently, general surgery residencies have experienced difficulties in attracting medical students into their ranks. The causes of this problem are manifold and are discussed at length in other works.13–15 Recent proposals to change the training pathway of general surgical subspecialists to "3 + 3" year programs may broaden the appeal of a career in surgery. For example, the American Board of Thoracic Surgery recently changed their requirement for fellowship trainees, allowing them to be board certified in thoracic surgery without completing a general surgery residency.16 Similar changes have been proposed for vascular surgery and may eventually gain wide acceptance.17 These efforts are an important response to the declining interest in general surgery and increasing demand for subspecialists. However, whatever changes do occur in the surgical workforce will come about slowly. For the foreseeable future, the rate at which general surgeons (and subspecialists of general surgery) are trained will remain fairly constant.

A second option is to ask surgeons to operate more efficiently; for the purposes of this discussion, we define efficiency as the amount of operative work performed per surgeon per year. There are already signs that the general surgical workforce is being asked to work more efficiently. Zelenock et al.18 reported that in their academic institution, the number of operations performed per surgeon increased 30% between 1981 and 1995. Similar trends are seen in community settings. In a recent survey conducted by the American Medical Group Association, general surgeons in group practices increased the amount of work per surgeon by 4% between 1998 and 2001.19

How can surgeons provide more care without sacrificing quality? It is clearly undesirable for surgeons to increase the speed at which they operate. It is also impractical to expect surgeons to increase their work hours by 25% to 40% over the next 20 years. Any improvements in surgical efficiency might therefore be focused on enabling the surgeon to focus more on operative work. The burden of nonoperative work needs to be evaluated in terms of its ability to be performed by nonsurgeons. Nonphysician clinicians (NPCs) are a relatively untapped resource that may help surgeons to meet the burgeoning demand for services. In a recent analysis of data from the Medicare Expenditure Panel Survey, the percentage of individuals in the United States seen by an NPC increased significantly between 1987 and 1997.20 This increase, however, was due not to an increase in the number of patients who saw an NPC instead of a physician, but rather to an increase in the number of visits in which a patient saw an NPC in addition to a physician. The problems addressed by NPCs were primarily outpatient conditions. In the future, NPCs will likely have an expanded role in helping surgeons to care for surgical patients.

In summary, the US health-care system will soon begin seeing an enormous growth in demand for oncological procedures. This demand is not elastic. If a significant shortage of surgeons performing these procedures does occur, the result will inevitably be decreased access to care. Women and elderly patients, the primary consumers of oncological procedures, will feel this shortage most acutely. To prevent this from happening, our ability as surgeons to cope with an increased burden of work needs to be critically evaluated and improved.


   FOOTNOTES
 
Presented at the Society of Surgical Oncology meeting, Los Angeles, California, March 2003.

Over the next two decades, the US population will experience dramatic growth in the number and proportion of older individuals. As a result of these population shifts, we project a 24% to 51% increase by 2020 in the utilization of oncological procedures. Surgeons need to critically evaluate their ability to cope with this increased burden of work.

Received for publication March 7, 2003. Accepted for publication August 5, 2003.


   REFERENCES
TOP
 ABSTRACT
 INTRODUCTION
 METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 

  1. Anderson RN, DeTurk PB. United States Life Tables, 1999 (National Vital Statistics Report, Vol 50, No. 6). Hyattsville, MD: National Center for Health Statistics, 2002.
  2. Population Change and Distribution. Census 2000 Brief. US Department of Commerce: Economics and Statistics Administration, 2001.
  3. Popovic J. 1999 National Hospital Discharge Survey: Annual Summary With Detailed Diagnosis and Procedure Data. Hyattsville, MD: National Center for Health Statistics, 2001.
  4. Graduate Medical Education National Advisory Committee. Summary Report of the Graduate Medical Education National Advisory Committee to the Secretary, Department of Health and Human Services, September 20, 1980. Vol 1. Hyattsville, MD: Department of Health and Human Services, 1980.
  5. Etzioni DA, Liu JH, Maggard MA, Ko CY. The aging population and its impact on the surgery workforce. Ann Surg 2003; 238: 170–7.[CrossRef][Medline]
  6. Kwakwa F, Biester TW, Ritchie WP Jr, Jonasson O. Career pathways of graduates of general surgery residency programs: an analysis of graduates from 1983 to 1990. J Am Coll Surg 2002; 194: 48–53.[Medline]
  7. Inciardi JF, Lee JG, Stijnen T. Incidence trends for colorectal cancer in California: implications for current screening practices. Am J Med 2000; 109: 277–81.[Medline]
  8. Cress RD, Morris CR, Wolfe BM. Cancer of the colon and rectum in California: trends in incidence by race/ethnicity, stage, and subsite. Prev Med 2000; 31: 447–53.[CrossRef][Medline]
  9. Swan J, Breen N, Coates RJ, et al. Progress in cancer screening practices in the United States: results from the 2000 National Health Interview Survey. Cancer 2003; 97: 1528–40.[CrossRef][Medline]
  10. Breen N, Wagener DK, Brown ML, et al. Progress in cancer screening over a decade: results of cancer screening from the 1987, 1992, and 1998 National Health Interview Surveys. J Natl Cancer Inst 2001; 93: 1704–13.[Abstract/Free Full Text]
  11. Mandel JS, Church TR, Bond JH, et al. The effect of fecal occult-blood screening on the incidence of colorectal cancer. N Engl J Med 2000; 343: 1603–7.[Abstract/Free Full Text]
  12. Mandel JS, Bond JH, Church TR, et al. Reducing mortality from colorectal cancer by screening for fecal occult blood. Minnesota Colon Cancer Control Study. N Engl J Med 1993; 328: 1365–71.[Abstract/Free Full Text]
  13. Bland KI, Isaacs G. Contemporary trends in student selection of medical specialties: the potential impact on general surgery. Arch Surg 2002; 137: 259–67.[Abstract/Free Full Text]
  14. Henningsen JA. Why the numbers are dropping in general surgery: the answer no one wants to hear—lifestyle! Arch Surg 2002; 137: 255–6.[Free Full Text]
  15. Organ CH Jr. The generation gap in modern surgery. Arch Surg 2002; 137: 250–2.[Free Full Text]
  16. American Board of Thoracic Surgery. Notice From the American Board of Thoracic Surgery, 2001. Available at: http://www.ctsnet.org/doc/6678. Accessed July 1, 2003.
  17. American Board of Thoracic Surgery. Am Board Vasc Surg Newslett 2002 (Spring). Available at: http://www.vascularweb.org/file/newsletter.pdf. Accessed July 3, 2003.
  18. Zelenock GB, Stanley JC, More RA, et al. Differential clinical workloads among faculty at a major academic health center. Ann Surg 1997; 226: 336–45;discussion 345–7.[CrossRef]
  19. Medical Group Compensation & Productivity Survey. Alexandria, VA: American Medical Group Association, 2002.
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