30. Paediatric malignancies - The GEC-ESTRO Handbook of Brachytherapy

Paediatric malignancies

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THE GEC ESTRO HANDBOOK OF BRACHYTHERAPY | Part II Clinical Practice Version 1 - 01/09/2023

11. MONITORING

RMS patients, 125/275 (45.6%) had tumour size > 5 cm, 31/275 (11.3%) had alveolar histology, 12/275 (4.4%) had regional lymph node involvement and 15/175 (5.5%) had distant lymph node or visceral metastatic sites. The main tumour sites were urogenital sites, with 172 BP RMS and 87 gynaecological tumours. In this series, BT was planned on 2D radiographs in 180 (59.0%) patients and on 3D imaging in 125 patients (41.0%). Among patients with RMS, median follow-up was 55 months (range: 1 month – 48 years). At five years, local control probability was 92.4% (95% CI = 88.1-96.9) for BP RMS and 94.2% (95% CI = 88.1-100) for gynaecological RMS. The local control probability was poorer for perineal RMS (62.5% (95% CI = 38.2-100)). Overall survival probability in the whole cohort was 93.3% (CI95%:90.1-96.5) [11]. Another large experience comes from India, with a publication on 105 children (median age 10 years) treated for soft tissue sarcoma [35]. Treatment included wide local excision and BT with or without external beam radiotherapy (19% of patients). Synovial sarcoma (22%) was the most frequent histology. Eighty-five (81%) received BT alone. After a median follow-up of 65 months, local control, disease-free survival, and overall survival at 10 years were 83, 66, and 73%, respectively. On multivariate analysis, authors found higher local control probability for patients with tumours <5 cm versus >5 cm (p = 0.03) and trunk/extremity versus head and neck/genitourinary sites (P = 0.002). Wound complications were reported in 6%. Subcutaneous fibrosis (25%) and limb oedema (6%) were the most frequent late complications [35]. For head and neck and orbital tumours, the most mature data are available from the Amsterdam experience [8, 63, 68]. In a series of 42 with non-parameningeal and parameningeal RMS patients published in 2009 and treated at doses ranging from 40 to 50 Gy (including 11 patients referred at time of relapse), the authors reported 3 patients with local recurrences and six having both local and distant recurrence. Overall, the 5-year survival rate was 70% in the primary treatment group and 82% for the salvage group. In an analysis of failure patterns, it was reported that five of six patients with relapse in the residual area had gross total or debulking (incomplete) surgery, suboptimal position of the mould for BT, or both. These data show the importance of both high-quality surgery and brachytherapy to achieve high local control [8]. Factors found to be a contraindication to perform the AMORE procedure are: • Intracranial extension • Invasion of the nasopharynx • Involvement of the orbit leading to exenteration (except in radiorecurrent disease) • Encasement of the carotid artery (more than 50% surface contact) • Invasion into the pterygopalatine fossa (contraindicated if adequate positioning of the mould cannot be accomplished) For orbital brachytherapy in combination with local surgery (mostly eye preservation) the 10-year event free survival and overall survival was found to be 65% and 89%, respectively [63]. Promising results were also reported from smaller series (usually involving less than 20-30 patients) treated with HDR treatments, mainly for limb tumours or bladder prostate RMS [23, 39].

During irradiation, regular checks must be carried out as for adult patients, but specific checks are mandatory dependent on the age of the child and the support of the family. The treatment room is equipped with Tv monitoring, WiFi, and viewing facilities. To preserve the quality of the implant, it is necessary to check clinically twice a day that there is no displacement of the plastic tubes or needles in an interstitial implant or of the applicator (mould) in endocavitary BT. X ray or sectional image control is mandatory when there is any suspicion of movement of the material [12, 13]. For HDR treatments, a minimal interval of 6 hours should be followed between two fractions and cross-sectional imaging is necessary prior to each fraction. The experience with PDR BT shows that compliance issues can be managed successfully in expert institutions, and they seem to be of relatively minor importance when compared with the long term results, in particular in terms of minimizing late side effects [13]. The compliance during continuous or pulsed irradiation for a period of several days is usually satisfactory, even in young children. The whole team including the brachytherapist, nurses, technologists, anaesthesiologist, psychosocial staff, family, and paediatric oncologist must however collaborate closely to support the child in coping with the various situations creating discomfort. General anaesthesia during the whole treatment course is not required. To minimize pain and psychological problems related to isolation, “preventive” soft sedation and pain treatment can be prescribed, thus reducing discomfort. The continuous support of the family and the care of the nurses is crucial throughout the day and night and in particular during meals. With regard to other forms of supportive and “preventive” care (e.g., anti-inflammatory treatment, antibiotics), these depend on the site, the procedure and the specific risks. In general, they are similar to those in adults (see the respective organ chapters). Local control, survival Numerous series report high to excellent local control rates after BT for paediatric tumours [5, 12, 13, 14, 15, 21, 22, 23, 24, 26, 28, 30, 35, 39, 45, 46, 47, 48, 49, 53, 54, 58, 66, 67]. Most clinical data for paediatric BT comes from LDR or PDR treatments and for treatment of urogenital sites [19]. The largest study for paediatric BT was published from Gustave Roussy including 305 patients (no retinoblastoma or CNS primary malignancy) with a mean age of 2.2 years (range: 1.4 months–17.2 years) at diagnosis. In this cohort, 270 (88.5%) patients had localised disease, 16 (5.2%) had regional lymph node involvement, and 19 (6.3%) had distant lymph node or visceral metastases. This series included 42 (13.8%) patients referred for local relapse/ progression. Primary tumour sites were mainly represented by genitourinary tumours, with 172 (56.4%) patients treated for a BP-RMS and 87 (28.5%) having a gynaecological cancer. Among 12. RESULTS