Place of Re-Irradiation in the Management of Local Relapses of Cavum Cancer

The rate of local control of nasopharyngeal carcinomas has increased more and more since the systematic use of conformal radiotherapy with intensity modulation. The treatment of local recurrences is essentially based on re-irradiation; but it is limited by the doses previously received by the organs at risk inseries. Goal of the study To assess the efficacy and toxicity of re– irradiation of local relapses of nasopharyngeal carcinoma. Material and method This is a retrospective study, including 12 patients re-irradiated at the National Institute of Oncology in Rabat for a local or loco regional relapse between 2015 and 2020. Results Among 600 irradiated patients, 12 patients presented a local or loco regional recurrence for which they received re-irradiation with intensity modulation. The average age of the patients at the time of the initial diagnosis was 40.8 years (extremes of 22 and 52 years). The tumor was initially classified according to the AJCC 2017 classification as stage II, stage III and stage IV respectively in 2 cases (16%), 4 cases (34%) and 6 cases (50%). The initial treatment was based on neo- adjuvant chemotherapy followed by concomitant radio-chemotherapy in 9 patients (75%) and concomitant radio-chemotherapy alone in 3 patients (30%). Initial irradiation was according to a conventional three-dimensional technique having delivered a total dose of 70 Gy at the rate of 2 Gy per session. All patients were in complete remission. The mean time to local relapse was 7 years (range: 3 to 10 years). The diagnosis was confirmed by anatomo pathological study in all patients. The recurrence was classified as stage II, stage III and stage IV respectively in 3 cases (25%), 5 cases (41%) and 4 cases (33%). On the therapeutic level, 5 patients (41%) received neoadjuvant chemotherapy followed by concomitant radio-chemotherapy; 6 patients (50%) received concomitant radio-chemotherapy alone and one patient received exclusive radiotherapy. Reirradiation was intensity-modulated byArc Therapy, having delivered a total dose of 60 Gy in all patients at reasonof 2Gy per fraction. After a mean follow-up of 19 months (range: 10 months–34 months), sevenpatients were in complete remission; two died of the disease after an average follow-up of 10 months and three patients are lost to follow-up. The late toxicity of re-irradiation was increased auditory toxicity (grade 3 becoming grade 4) in 4 patients, trismus in two patients and cervical fibrosis in two patients. Conclusion Re-irradiation is the only salvage treatment for recurrences of nasopharyngeal carcinoma, precisely conformal radiotherapy with intensity modulation which makes it possible to deliver sufficient doses to the level of the tumor volume while sparing the organs at risk which have already been irradiated; however, given the associated toxicity, patients must be carefullyselected