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907Vol. 212, No. 5, May 2011 Letters

Reply

David L Morris, MD, PhD, Terence C Chua,BScMed (Hons), MBBS

Sydney, Australia

We appreciate the comments of Raghav and colleaguesfrom MD Anderson Cancer Center and their suggest-ion that malignant dedifferentiation observed in pseu-domyxoma peritonei (PMP) as described in our studycould potentially be a result of various confounding factorsthat include tumor heterogeneity, tumor sampling, andsubjective factors used in grading. As described by Ronnettand coworkers,1 the pathologic grade of PMP may be clas-ified into 3 categories: diffuse peritoneal adenomucinosis,eritoneal mucinous carcinomatosis intermediate, anderitoneal mucinous carcinomatosis. From our experience,he pathologic grade is only often reliably assigned in theands of an experienced pathologist who is familiar withhis disease. A significant proportion of patients referred tos have a pathology report with a diagnosis of mucinousdenocarcinoma. Therefore, we often make requests forrchived slides of patients presenting with mucinous tu-ors for reevaluation before embarking on surgery. All

atients treated in our institution had their tumor speci-ens examined by local pathologists who were familiarith this disease. From analyzing the pathologic reports,e showed that 16% of patients developed malignant ded-

fferentiation from their original tumor grade, and this hadetrimental impact on their overall survival. Such phenom-na may explain the development of pulmonary metastasesnd other hematogenously disseminated extra-abdominaletastatic sites observed in patients with PMP.2,3 We be-

lieve the occurrence of hematogenous dissemination islikely possible in the disease history only if the intra-abdominal disease has been adequately treated. Cytoreduc-tive surgery and intraperitoneal chemotherapy have beenshown to achieve long-term survival. It is during this pro-longed survival time in some unfortunate cases when dis-ease recurs and subsequent treatment with repeated cytore-ductions are undertaken that hematogenous disseminationmay be potentially observed. In patients who have not beencuratively treated by cytoreduction, the demise is often aresult of the morbidity and mortality induced by the bulk-ing intra-abdominal mucinous tumor. Raghav and col-leagues, however, reported 11 patients who had at least 2surgical specimens of which only 1 patient dedifferentiatedfrom a moderately differentiated tumor to a poorly differ-entiated tumor at secondary cytoreduction.They also men-tioned 11 patients who had 1 surgical and 1 biopsy speci-

men, which we believe would not be adequate to evaluate

any histologic dedifferentiation, given the potential of falsesampling as alluded to by the authors.

In summary, we agree that there is potential that inade-quate sampling, tumor heterogeneity, and interobservervariation could confound the results. However, lack of uni-form classification is unlikely the case in our institution.Malignant dedifferentiation may occur in patients whohave a prolonged disease history of PMP following re-peated cytoreductions, and this theory may explain thepresence of hematogenously disseminated metastatic sites.

REFERENCES

1. Ronnett BM, Zahn CM, Kurman RJ, et al. Disseminated perito-neal adenomucinosis and peritoneal mucinous carcinomatosis. Aclinicopathologic analysis of 109 cases with emphasis on distin-guishing pathologic features, site of origin, prognosis, and rela-tionship to “pseudomyxoma peritonei.” Am J Surg Pathol 1995;19:1390–1408.

2. Mortman KD, Sugarbaker PA, Shmookler BM, et al. Pulmonarymetastases in pseudomyxoma peritonei syndrome. Ann ThoracSurg 1997;64:1434–1436.

3. Lee BY, Kim HS, Lee SH, et al. Pseudomyxoma peritonei: extra-peritoneal spread to the pleural cavity and lung. J Thorac Imaging2004;19:123–126.

Disclosure Information: Nothing to disclose.

Comparing the Quality of SurgicalCare: A Reason for Caution

Danny Chu, MD, FACS, David H Berger, MD, FACS,aisal G Bakaeen, MD, FACS

Houston, TX

We read with interest the article by Matula and colleagues1 com-paring the quality of surgical care between Veterans Affairs (VA)andprivatehospitals.Acrossa spectrumofsurgicaldisciplines, theauthors demonstrated that the outcomes were generally similarbetween VA and private hospitals, with some exceptions.

Intheir systematic review, theauthors selected16articlesoutofmore than 200 published in the literature relating to veterans’health care. The authors made a genuine effort to select high-quality comparative studies. Nevertheless, it is nearly impossibletoaccount for thedifferences in risk-adjustment strategies andthevaried definitions of the outcome measures in the studies that theauthors analyzed. This heterogeneity is a significant confounderof the study of Matula and colleagues1; therefore, the results needto be interpreted with caution.

Another limitation, one acknowledged by the authors, is

that none of the studies they reviewed incorporated data col-

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908 Letters J Am Coll Surg

lected after 2004, which calls into question whether their find-ings reflect contemporary realities. Specifically, the authorssuggested that the quality of cardiac surgical care is lower at VAhospitals than in the private sector, but this conclusion wasbased on a single outdated (1993–1996) study.2

In fact, a wealth of data obtained from rigorously maintainednationwide databases and more contemporary studies point tothe opposite conclusion. All VA cardiac surgery programs are re-quired to report all cardiac surgery cases to the Continuous Im-provement in Cardiac Surgery Program, and as many as 80% ofnon-VA cardiac surgery centers voluntarily report their cases tothe Society ofThoracic Surgeons’ National Cardiac Database. Inboth of these databases, Grover and colleagues3 found the samelow (0.9) observed-to-expected mortality ratio among cardiacsurgical patients. Likewise, when we compared the outcomes ofisolated coronary artery bypass grafting procedures at our VAhospital with those at civilian hospitals that contribute to theNationwide Inpatient Sample database, we found that al-though the VA patients were sicker, their postoperative mor-tality was significantly lower than that of the Nationwide In-patient Sample patients.4 But beyond the realm ofomparative studies and their potential biases, one can learn aair bit about the quality of cardiac surgical care at the VA fromhe excellent graft patency results and outcomes reported byecent large, multicenter VA studies.5,6

Although Matula and colleagues1 addressed a provocativessue, their results may not reflect the current standards ofardiac surgery or other surgical specialties at VA hospitals.herefore, these findings must be interpreted with caution.

REFERENCES

1. Matula SR, Trivedi AN, Miake-Lye I, et al. Comparisons of qual-ity of surgical care between the US Department of Veterans Af-fairs and the private sector. J Am Coll Surg 2010;211:823–832.

2. Rosenthal GE, Vaughan Sarrazin M, Hannan EL. In-hospital mor-tality following coronary artery bypass graft surgery in VeteransHealth Administration and private sector hospitals. Med Care 2003;41:522–535.

3. Grover FL, Shroyer AL, Hammermeister K, et al. A decade’sexperience with quality improvement in cardiac surgery using theVeterans Affairs and Society of Thoracic Surgeons national data-bases. Ann Surg 2001;234:464–474.

4. Choi JC, Bakaeen FG, Huh J, et al. Outcomes of coronary sur-gery at a Veterans Affairs hospital versus other hospitals. J SurgRes 2009;156:150–154.

5. Shroyer AL, Grover FL, Hattler B, et al. On-pump versus off-pump coronary-artery bypass surgery. N Engl J Med 2009;361:1827–1837.

6. Goldman S, Sethi GK, Holman W, et al. Radial artery grafts vssaphenous vein grafts in coronary artery bypass surgery: a ran-domized trial. JAMA 2011;305:167–174.

Disclosure Information: Nothing to disclose.

Reply

Sierra R Matula, MD, Isomi Miake-Lye, BA,Glassman A Peter, MBBS, MSC, Paul Shekelle, MD, PhD,teven Asch, MD, MPH, Amal NTrivedi, MD, MPH

Providence, RI

We thank Chu and colleagues for their interest and com-ments regarding our recent study evaluating the literaturethat compares quality of surgical care in Veterans Affairs(VA) and non-VA settings.1 Inclusion criteria in our reviewllowed for studies assessing data from 1990 through Au-ust 2009; of the studies that met all criteria for inclusion,owever, none analyzed data after 2004. Although a fewtudies found more favorable outcomes in the non-VA set-ings, other studies found better outcomes in the VA. Ineneral, however, based on the available evidence, we foundhat surgical morbidity and mortality were comparable be-ween the VA and non-VA settings. Interestingly, Stremplend coworkers2,3 reached similar conclusions in their earlier

review of postoperative outcomes in 1984 to 1988. Weagree with Chu and colleagues that newer studies areneeded.

As Chu and colleagues pointed out, there are well-established data collection systems to evaluate the qualityof cardiothoracic surgery. In 2001, Grover and associates4

presented an overview of the VA and the Society of Tho-racic Surgeons data sets. This article is useful to understandthe resources that can be used in cardiothoracic surgery toevaluate quality of care; however, it was not a formal com-parison of quality between VA and non-VA care and there-fore was not included in our systematic review. A recentstudy5 cited by Chu and colleagues compared mortalityollowing coronary surgery in VA hospitals with mortalityn private sector hospitals. Although this study presentedome preliminary intriguing findings, the statistical analy-is was insufficient to be included in our review.

In addition to the detailed information available on car-iac surgery from both the Society of Thoracic Surgeonsnd the VA, there are well-established data collection sys-ems in general surgery that stem from work done by lead-rs in the field over the past few decades.6,7 These data canerve as resources to update comparisons of quality in theA and non-VA settings. We appreciate Chu and col-

eagues for highlighting the importance of pursuing thisork.

REFERENCES

1. Matula SR, Trivedi AN, Miake-Lye I, et al. Comparisons of

quality of surgical care between the US Department of Veter-