Second malignancies after permanent implant prostate cancer brachytherapy: A single-institution study of 675 patients treated between 1999 and 2003.

To analyse the rate of secondary malignancies observed in a series of 675 prostate cancer patients who underwent a permanent implant brachytherapy between 1999 and 2003, and to compare the incidence with the expected rate in a matched general French population.

The cohort included low-risk patients and a selection of "favourable-intermediate" risk patients. All patients were homogeneously treated using an intraoperative dynamic planning prostate brachytherapy technique, with loose 125-iodine seeds and a prescription dose of 145Gy. The mean follow-up was 132 months.

The 10-year overall survival for the entire cohort was 92% (95% confidence interval [CI]: 90-94). The 10-year relapse-free survival rate was 82% (95% CI: 79-85). Overall, 61 second cancers were registered. When comparing with a matched general French population, the standard incidence ratio (SIR) for bladder cancer was 1.02 (95% CI: 0.46-1.93). For colorectal cancer, the SIR was 0.45 (95% CI: 0.19-0.89). For lung cancer, the SIR was 0.38 (95% CI: 0.17-0.76). The SIR for all cancers was 0.61 (95% CI: 0.47-0.79). When excluding secondary colorectal and lung cancers (both with low SIRs in this series), the SIR for all cancers was 1.06 (95% CI: 0.77-1.29).

With a mean follow-up of more than 11 years, this series does not detect any excess risk of second cancers associated with permanent implant prostate brachytherapy. However, due to power limitation, a small increase in the risk of secondary malignancies cannot be totally ruled out.

Cancer radiotherapie : journal de la Societe francaise de radiotherapie oncologique. 2017 May 09 [Epub]

J-M Cosset, L Belin, G Wakil, T Flam, N Thiounn, N Pierrat, D Pontvert, A Savignoni, L Chauveinc

Institut Curie, 26, rue d'Ulm, 75005 Paris, France; Centre Charlebourg-La Défense, groupe Amethyst, 92250 La Garenne-Colombes, France. Electronic address: ., Institut Curie, 26, rue d'Ulm, 75005 Paris, France., Institut Curie, 26, rue d'Ulm, 75005 Paris, France; Charles Lemoyne hospital, 3120, boulevard Taschereau, Greenfield Park, J4V 2H1 Montréal, QC, Canada., Institut Curie, 26, rue d'Ulm, 75005 Paris, France; Fondation Saint-Jean-de-Dieu-Oudinot, 19, rue Oudinot, 75007 Paris, France., Hôpital européen Georges-Pompidou, 20, rue Leblanc, 75015 Paris, France., Institut Curie, 26, rue d'Ulm, 75005 Paris, France; Centre de radiothérapie Hartmann, 4, rue Kléber, 93200 Levallois-Perret, France.