Double irradiation for macroscopic radioresistance or recurrence of melanomas of the posterior uvea: clinical, ballistic, therapeutic and prognostic aspects. Series of 19 cases among 462 patients

We describe two comparative series of patients treated with double-dose betaraysbrachytherapy (106 Ruthenium) between 1983 and 1994, and double-dose proton beam therapy between 1991 and 1996. The indications for double-dose irradiation with the same radio-element corresponded to "macroscopically abnormal" situations: immediate and prolonged radioresistance, recurrence or secondary radioresistance. Thirteen cases are called series 1 (Ruthenium) and 6 cases are called series 2 (protons). The series 1 allows a more reliable study as far as follow-up is higher (5.8 to 7.5 years) than in series 2 where the follow-up is shorter (13.6 to 29 months). Although double-dose irradiation was macroscopically efficient in 11 out of 13 cases in series 1, and in 3 out of 6 cases in series 2 (stabilization or decrease of tumour height measured before the second therapeutic session), 2 patients are deceased and 1 has a metastatic disease in the group "recurrence" of Ruthenium serie. Another one has also a metastatic disease in the group "recurrence" of protons series. Nevertheless double-dose radiotherapy allows a complementary decrease or stabilization of tumour height after a first session. It also decreases the indications for enucleation if there is no severe anatomic complications, when a tumour does not regress or recurs after a first session of radiations.