Risk of secondary malignancies in testicular cancer

While in the United States the preferred treatment for stage I mixed germ cell tumors has been retroperitoneal lymphadenectomy, adjuvant chemotherapy has been more commonly used in Europe. 

For stage I seminoma, treatment has varied between observation, prophylactic radiotherapy, and single-dose carboplatin. One of the criticisms against the use of chemotherapy or radiation has been the potential risk for secondary malignancies.

In the September 2005 issue of JNCI, Travis and colleagues from the Division of Cancer Epidemiology and Genetics from the NCI present data from 14 tumor registries in Europe and North America. New incident solid tumors were identified in 40,576 patients with testicular cancer surviving more than 1 year. 

Among those patients surviving more than 10 years, the relative risk of a secondary malignancy was 1.9 (95% confidence interval, 1.8 to 2.1). This increased risk remained elevated for 35 years. The risk of a secondary tumor decreased with increasing age at diagnosis.

Over sixty percent of secondary malignancies were carcinomas of the lung, colon, pancreas, and stomach. There were no statistically significant differences in the risk of secondary malignancies between patients with seminomas and non-seminomatous germ cell tumors.  In patients with seminomas treated with retroperitoneal radiation, the relative risk of a secondary solid tumor was 2.0 (95% CI, 1.9 to 2.2), 1.8 for patients treated with chemotherapy, and highest (2.9) for patients treated with both radiotherapy and chemotherapy.

While selective use of chemotherapy or radiotherapy is very effective in the treatment of germ cell tumors, these data from large cohort of patients confirms real and significant risk of secondary tumors. While often as clinicians we focus on primary tumor surveillance, these sobering facts underscore the need for heightened awareness in detecting potential secondary malignancies even decades after the patient is declared "disease-free".

Reference:

J Natl Cancer Inst. 2005 Sep 21; 97(18):1354-65.

http://www.ncbi.nlm.nih.gov/entrez/

Travis LB, Fossa SD, Schonfeld SJ, McMaster ML, Lynch CF, Storm H, Hall P, Holowaty E, Andersen A, Pukkala E, Andersson M, Kaijser M, Gospodarowicz M, Joensuu T, Cohen RJ, Boice JD Jr, Dores GM, Gilbert ES

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