BERKELEY, CA (UroToday.com) - Testicular cancer is the most common cancer in men aged 15-44 years. Diagnostic imaging, particularly computed tomography (CT), is essential for staging and surveillance. Quantification of radiation dose in testicular cancer patients was precipitated by concerns regarding cumulative effective dose (CED) (the total radiation dose received by a patient over time from diagnostic imaging) and its implications for this young population with a good overall prognosis. There is much debate about the relationship between cumulative radiation exposure and quantifiable risk of cancer induction. High CED (greater than 75mSv) should be avoided if possible, especially the use of CT in younger patients.
Radiologic surveillance is part of standard practice for management of testicular cancer. Our study shows that radiologic surveillance in these patients is associated with high CED (OR 2.1, CI 1.5-2.8). Overall, 77.5% (93/120) of patients received high CED (> 75mSv). These CED values far exceeded doses recorded in recent studies from our center, in patients with chronic diseases including Crohn’s disease and cystic fibrosis, where 15.5% and 10.43% of patients receiving CED > 75mSv, respectively.[3, 4]
The duration of surveillance specified in recent European Society for Medical Oncology (ESMO) surveillance guidelines for testicular cancer was adhered to in this study. The abdomen and pelvis were the most commonly imaged anatomical areas; 54% of CED from CT was administered to these areas, which contain organs at high risk of radiation-induced malignancy . In testicular cancer, where most recurrences are in the retroperitoneum and not in solid organs, low-dose CT protocols using partial or full iterative reconstruction and automated tube current modulation have the potential to reduce radiation exposure without compromising diagnostic accuracy in detection of lymph node metastases. These technologies may reduce the requirement for retroperitoneal lymph node dissection in selected groups if sensitivity of CT for detection of metastases is maintained.
Considering the low age profile and good ¬prognosis of testicular cancer patients, radiation doses from diagnostic imaging need to be optimised. Patients with stage I testicular cancer in our study underwent significantly longer surveillance than stage II patients despite less advanced disease. Surveillance alone is preferred to either single-agent carboplatin or infra-diaphragmatic radiotherapy in patients with stage IA and IB seminoma according to NCCN Version 2.2011 guidelines. Management of these early-stage patients requires careful balancing of risk of recurrence or metastasis, and risk of treatment or imaging side effects, as there may be potential for harm. Dose tracking software has the potential to benefit these patients by alerting clinicians to individuals with risk of this CED. The findings of the present study highlight the need for further research in the area of radiation protection, and prospective monitoring of patients at risk of high CED from diagnostic radiation.[3, 4, 8]
Interestingly, disease progression was not found to be associated with high CED (> 75mSv), likely because progression of disease did not affect surveillance duration. Logistic regression analysis showed that only length of surveillance was associated with a high CED. Tailored surveillance based on disease stage may be a change to consider in future guidelines. For example, no progression of stage I or II disease was observed beyond three years from diagnosis, leading to our suggestion of a potential reduction in radiologic surveillance in these patients. Assessment of a larger cohort would be required to validate this hypothesis.
Since the publication of our study, other estimations of CED in similar cohorts have been published, focusing on surveillance and its association with high CED and secondary cancer risk. Chien et al. investigated frequency of surveillance in non-Hodgkins lymphoma, finding that among 180 secondary primary malignancies, there was a significantly higher incidence of cancers of the breast, stomach and liver and biliary tract in those patients undergoing more CT investigations. A recent study by Estay et al. examined CED in patients with inflammatory bowel disease, quantifying high CED as > 50mSv. 19.5% of Crohn’s disease patients and 2.5% of ulcerative colitis patients were exposed to at least 50mSv of diagnostic radiation, an exposure considerably less than that seen in our cohort of testicular cancer patients.
In conclusion, a large proportion of patients undergoing surveillance after diagnosis of testicular cancer receive high CED from diagnostic imaging, most notably CT of the thorax, abdomen and pelvis. We encourage the development of strategies to monitor CED, increase the use of MRI, and optimize CT protocols to tailor imaging frequency to likelihood of cancer recurrence or progression.
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- Schmoll H-J, Jordan K, Huddart R et al. Testicular seminoma: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up. Ann Oncol 2010 21:v140–v146
- Kalra MK, Maher MM, Toth TL et al. Radiation from “extra” images acquired with abdominal and/or pelvic CT: effect of automatic tube current modulation. Radiology 2004 232:409–414
- NCCN Clinical Practice Guidelines in Oncology Version 2.2011. Testicular cancer - pure seminoma.
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C. J. Sullivan,a K. P. Murphy,a, b P. D. McLaughlin,a, c M. Twomey,a K. N. O’Regan,a D. G. Power,d M. M. Maher,a, b and O. J. O’Connora, b as part of Beyond the Abstract on UroToday.com. This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.
aDepartment of Radiology, Cork and Mercy University Hospitals, Wilton, Cork, Ireland
bDepartment of Radiology, University College Cork, Cork, Ireland
cDepartment of Emergency and Trauma Radiology, Vancouver General Hospital, Vancouver, British Columbia, Canada
dDepartment of Medical Oncology, Cork and Mercy University Hospitals, Cork, Ireland