ADVANCES IN MEDICINE have made organ transplantation a routine surgical procedure in the United States, with more than 700 transplant centers performing more than 20,000 solid-organ transplants each year.
Modern immunosuppressive therapy provides relative protection from rejection; however, it can also render the transplant recipient susceptible to increased incidence of infectious complications and malignancies.
Several authors have estimated the overall incidence of malignancy in the transplant recipient to be as high as 20%. The most common malignancies encountered are skin and lymphatogenous malignancies, which constitute 43% of all de novo transplant-related malignancies.
Both of these histologic malignancies occur in high turnover tissue and appear to be most susceptible to environmental factors. These factors, viral co-stimulators, induction agents, and antimetabolite therapy have all been associated with the development of de novo malignancies.
It has been established in the Japanese literature that early identification increases the opportunity for surgical resection, which in turn results in increased patient survival.
In the United States, where there is no systematic screening program, gastric cancer is often detected at late stages, resulting in a dismal prognosis with 5-year survivals varying from 5% to 15%.
The earlier detection of gastric cancer in transplant recipients (50% stages I and II) may result largely from the high frequency of upper endoscopy and abdominal computed tomography performed in these patients. Though the frequency and diligence with which they are performed varies from institution to institution, endoscopies are often used for surveillance of infectious agents or for mild symptomatology.
In the current series, the majorities of gastric cancers were stages I and II and were identified
from upper endoscopies (n = 18) or computed tomographies (n = 4) performed for reasons other
than evaluation of gastrointestinal symptoms. Despite their incidental nature, those lesions identified by computed tomography were often diagnosed as stage III lesions and were deemed
unresectable. The single exception was in one of the patients with stage II disease who had extensive gastric wall thickening, namely linitis plastica.
Overall, early diagnosis appeared to result in higher surgical resection rates, yielding higher survival rates. The overall resectability rate was 65%, and the resulting 5-year survival rate was 29%, which is significantly higher than a similarly reported series from the United States that had an overall 5-year survival of 5% to 15%. When subset analysis is performed, patients with gastric cancer identified through incidental measures had a 40% 5-year survival rate. This survival rate is nearly equivalent to the 50% 5-year survival rate reported by the Japanese literature.
This suggests that patients with a significant smoking history, gastric polyps or prior gastric resection, and transplants recipients with H pylori infections should be closely monitored.
The incidence of nodal disease and overall survival according to stage is equivalent to the general
population. The use of adjuvant chemotherapy and radiation therapy was sporadic in this series
and had no apparent impact on survival. An interesting observation in this study was the poor
prognosis of patients maintained on chronic azathioprine. Because of the limited experience with
immunosuppression reduction or elimination in patients with gastric cancer, a potential beneficial
effect could not be identified
( 1 ).
References
1) Joseph F. Buell, Thomas Husted et al. Incidental diagnosis of gastric cancer in
transplant recipients improves patient survival. Surgery 2002;132:754-60. Pub Med
2) Smith CM, editor. UNOS 2000 Annual Report, The U.S. Scientific Registry of Transplant Recipients and The Organ Procurement and Transplantation Network, Richmond, Va.
