Elsevier

Oral Oncology

Volume 46, Issue 4, April 2010, Pages 271-275
Oral Oncology

Multivariate analyses to assess the effect of surgeon volume on survival rate in oral cancer: A nationwide population-based study in Taiwan

https://doi.org/10.1016/j.oraloncology.2010.01.006Get rights and content

Summary

Patients with oral cancer utilize considerable health care resources, particularly when wide resection of the tumor and reconstruction with pedicle flap/free flap is performed. This study was conducted to explore the relationship between survival rates and surgeon volume. A total of 1256 patients who underwent resections for oral cancer in 2005 were identified from the Taiwan National Health Insurance Research Database. Survival analysis, the Cox proportional regression model, and propensity score were used to evaluate the association between 3-year survival rates and surgeon caseloads. Oral cancer patients treated by high-volume surgeons (caseload 22–117) had better survival rates (hazard ratio [HR] = 0.656; 95% confidence interval [CI], 0.484–0.89; P = 0.007) using the Cox proportional regression model after adjusting for patients’ comorbid conditions, hospital, and surgeon characteristics. When analyzed by propensity score, the adjusted 3-year survival rate was 74% for patients treated by high-volume surgeons compared to 58% in the low/medium-volume group (P = 0.019). We concluded that for patients who underwent oral cancer resection and reconstruction, after adjusting for differences in the case mix, high-volume surgeons had better 3-year survival rates. Treatment strategies adopted by high-volume surgeons should be analyzed further and utilized more widely.

Introduction

The fact that increased caseload is associated with improved outcomes has been noted for three decades in many areas of health care, including acute myocardial infarction and many types of high-risk surgeries.[1], [2] “Practice makes perfect” may be valid for certain procedures such as open-heart and vascular surgery.3 Previous studies have also indicated that better quality is associated with high-volume hospitals.[4], [5] However, such a positive volume-outcome relationship is not well validated for other procedures and the effect of the relationship varies among different procedures and operations. Only a few studies have examined the effect of surgeon volume on outcomes for oral cancer or other head and neck cancers.[6], [7].

On a global scale, oral cancer is among the 10 most common forms of cancer. A trend of rising incidence is noted, irrespective of whether the examination is of Western countries or Asian countries such as Taiwan.[8], [9] The increasing economic burden of oral cancer treatment has become obvious. Of all cancers in males in Taiwan, oral cancer has been ranked fourth in incidence and mortality since 1995, and it may be associated with the increase use of betel quid consumption. Up to $1195 million (in U.S. dollars) was spent on the treatment of oral cancer in 2004. Furthermore, the number of young patients with oral cancer has continued to rise.

Wide resection of the tumor, neck dissection, and reconstruction with or without adjuvant chemo-radiotherapy is the main treatment strategy for oral cancer. With advances in tumor resection and flap reconstruction, functional outcomes, such as appearance, sensation, motor function, skeletal support, and quality of life have improved.10 However, the most important outcome is long-term survival and the surgeon caseload volume on survival rate deserves more attention.

In the majority of the prior studies on the association between caseload and survival rates, Cox regression model or logistic regression was routinely utilized and selection bias may exist.[6], [11], [12], [13], [14], [15] The purpose of this study was to examine the relationship between surgeon volume and survival rates in resection of oral cancer with reconstruction within a population-based database using Cox regression model and propensity score in order to minimize the effect of selection bias.

Section snippets

Materials and methods

The database contains a registry of contracted medical facilities, a registry of board-certified physicians, and monthly summaries for all inpatient claims. Because these were secondary data where individual patients were not identified, this study was exempt from full review by the internal review board. The study protocol conforms to ethical standards according to the Declaration of Helsinki published in 1964.

Results

A total of 431 deaths (34%) were identified from the total sample of 1256 patients who underwent wide resection of oral cancer with reconstruction in 2005. Operations and reconstructions for these patients were performed by 215 surgeons. The characteristics of the surgeons and patients are summarized in Table 1, Table 2. The majority of the patients were male (95%). There was no significant difference in distribution by age, gender, or Charlson Comorbidity Index score. The low-volume group was

Discussion

This study supported the hypothesis that management by high-volume surgeons improved overall survival from oral cancer with resection and reconstruction. Cox regression model showed that the risk of death for patients treated by high-volume surgeons was 0.656 times as high as the risk for those treated by low-volume group (P = 0.007). Using propensity score, the adjusted 3-year survival rate was 74% for patients treated by high-volume surgeons compared to 58% in the low/medium-volume group (P = 

Conflict of interest statement

None declared.

Acknowledgments

This study is based on data from the National Health Insurance Research Database provided by the Bureau of National Health Insurance, Department of Health, Taiwan, and managed by the National Health Research Institute. The interpretations and conclusions contained herein do not represent those of the Bureau of National Health Insurance, Department of Health, or the National Health Research Institute.

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