Radiotherapy and platinum chemotherapy increase malignant neoplasm risk in testicular cancer
medwireNews: Receipt of platinum-containing chemotherapy and radiotherapy is associated with an increased risk for solid subsequent malignant neoplasms (SMNs) compared with no such therapy, according to findings from a long-term follow-up of a large cohort of testicular cancer survivors.
Among 5848 men who had been treated for testicular cancer between 1976 and 2007 and had survived for at least 1 year, 350 solid SMNs developed during a median follow-up of 14.1 years, report Michael Schaapveld (Netherlands Cancer Institute, Amsterdam) and colleagues. This equated to a significant 1.8-fold increased risk for SMNs compared with the general population.
The increased risk for SMNs was seen in patients with seminoma and those with nonseminoma, at 1.52-fold and 2.21-fold. For patients with nonseminoma, the risk was increased at both supradiaphragmatic and infradiaphragmatic sites, whereas for patients with seminoma the increased risk was restricted to infradiaphragmatic sites.
With regard to treatment, receipt of platinum-based chemotherapy was associated with a significant 2.4-fold increased risk for any solid SMN versus no such therapy and versus surgery when received at doses of 400 mg/m2 and above. This was after taking into account age, radiation dose, and receipt of etoposide.
For gastrointestinal SMNs there was a significant linear dose–response relationship, with the risk increasing by 53% with each additional 100 mg/m2 of platinum-containing chemotherapy.
Similar trends were seen for urologic and lung SMNs, although the small numbers of these SMNs likely precluded significance, the authors remark.
Similarly, infradiaphragmatic irradiation was associated with a significantly increased risk for infradiaphragmatic SMNs compared with no para-aortic irradiation, with the hazard ratios for infradiaphragmatic and gastrointestinal SMNs increasing by 8% and 9%, respectively, for every 1 Gy increase in radiation dose. The rise was mainly driven by an increased risk for pancreatic, small intestine, and bladder cancers.
“[This] study has important implications for [testicular cancer] survivors as well as patients with newly diagnosed [testicular cancer],” write the researchers in the Journal of Clinical Oncology.
“The lower SMN risk with lower infradiaphragmatic radiation doses and fewer cycles of chemotherapy is reassuring for current patients.”
They conclude: “[E]fforts to reduce treatment intensity are important, as are efforts to increase awareness of these late effects and potentially screen if reliable screening tools are available.”
By Catherine Booth
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