Radiation-Induced Secondary Malignancy in Prostate Cancer: A Systematic Review and Meta-Analysis

Abstract

Objective: To investigate the risk of radiation-induced secondary malignancy in patients with prostate cancer. Methods: We identified 690 references from PubMed, Embase and the Cochrane Library before August 1, 2012, that reported secondary malignancy in patients with prostate cancer after receiving radiation therapy (RT), and finally four studies were included. We calculated summary estimates using random-effects meta-analysis. Results: The overall standardized incidence ratio (SIR) of secondary malignancy in patients with prostate cancer receiving RT to the general population was 1.14 (95% CI 1.04-1.32). In the subgroup analysis, no increment in radiation-induced secondary malignancy risk was detected. In terms of SIR with different follow-up intervals, there was no difference in SIR (>6 months; <5 years) (SIR = 1.19, 95% CI 0.75-1.89) and SIR (>5 years; <10 years) (SIR = 1.39, 95% CI 0.87-2.23). When the follow-up extended to >10 years, a significantly increased secondary malignancy risk was observed (SIR = 1.45, 95% CI 1.23-1.72). There is no significantly increased secondary malignancy risk in patients receiving no RT. Conclusion: RT is associated with increased secondary malignancy in patients with prostate cancer; this effect only become conspicuous more than 10 years after treatment.

Incidence of subsequent primary cancers and radiation-induced subsequent primary cancers after low dose-rate brachytherapy monotherapy for prostate cancer in long-term follow-up

“…In our cohort, every second metachronous SPC was diagnosed during the first 7.6 years. The risk to develop an SPC continued steadily, if not even more steeply, over the follow-up period, as shown in Figure 1, and the same phenomenon has been reported previously in studies with European and Western patient populations (16,17). As the OS of PCa patients is lengthening and the aging is a major risk factor for cancer development in general, this observation is not unexpected.…”

Second malignancies after radiotherapy for prostate cancer: systematic review and meta-analysis

“…[12][13][14] A previous meta-analysis lacked data from several important recent publications. 15 While direct radiation carcinogenesis has long been accepted, 16 there is evidence that irradiation of the prostate might contribute to carcinogenesis outside the irradiated area through radiation scatter and radiation induced genetic alterations without direct exposure because of increased reactive oxygen species [17][18][19] and…”

Stard

“…[ 2 , 3 ] Patients receiving radiation have a significantly reduced recurrence and metastasis rate, and disease-free survival is greater. [ 4 , 5 ] However, side effects of radiation have been widely reported, including impaired fertility, [ 6 ] secondary malignancy, [ 7 , 8 ] and lung metastasis. [ 9 ] Thus, accurate diagnosis of lymph invasion is critical to guide adjuvant therapy.…”