The effectiveness of 4DCT in children and adults: A pooled analysis

Kidney Disease in Childhood Cancer Survivors Treated With Radiation Therapy: A PENTEC Comprehensive Review

PURPOSE

Kidney injury is a known late and potentially devastating complication of abdominal radiation therapy (RT) in pediatric patients. A comprehensive Pediatric Normal Tissue Effects in the Clinic review by the Genitourinary (GU) Task Force aimed to describe RT dose-volume relationships for GU dysfunction, including kidney, bladder, and hypertension, for pediatric malignancies. The effect of chemotherapy was also considered.

METHODS AND MATERIALS

We conducted a comprehensive PubMed search of peer-reviewed manuscripts published from 1990 to 2017 for investigations on RT-associated GU toxicities in children treated for cancer. We retrieved 3271 articles with 100 fulfilling criteria for full review, 24 with RT dose data and 13 adequate for modeling. Endpoints were heterogenous and grouped according to National Kidney Foundation: grade ≥1, grade ≥2, and grade ≥3. We modeled whole kidney exposure from total body irradiation (TBI) for hematopoietic stem cell transplant and whole abdominal irradiation (WAI) for patients with Wilms tumor. Partial kidney tolerance was modeled from a single publication from 2021 after the comprehensive review revealed no usable partial kidney data. Inadequate data existed for analysis of bladder RT-associated toxicities.

RESULTS

The 13 reports with long-term GU outcomes suitable for modeling included 4 on WAI for Wilms tumor, 8 on TBI, and 1 for partial renal RT exposure. These reports evaluated a total of 1191 pediatric patients, including: WAI 86, TBI 666, and 439 partial kidney. The age range at the time of RT was 1 month to 18 years with medians of 2 to 11 years in the various reports. In our whole kidney analysis we were unable to include chemotherapy because of the heterogeneity of regimens and paucity of data. Age-specific toxicity data were also unavailable. Wilms studies occurred from 1968 to 2011 with mean follow-ups 8 to 15 years. TBI studies occurred from 1969 to 2004 with mean follow-ups of 4 months to 16 years. We modeled risk of dysfunction by RT dose and grade of toxicity. Normal tissue complication rates ≥5%, expressed as equivalent doses, 2 Gy/fx for whole kidney exposures occurred at 8.5, 10.2, and 14.5 Gy for National Kidney Foundation grades ≥1, ≥2, and ≥3, respectively. Conventional Wilms WAI of 10.5 Gy in 6 fx had risks of ≥grade 2 toxicity 4% and ≥grade 3 toxicity 1%. For fractionated 12 Gy TBI, those risks were 8% and <3%, respectively. Data did not support whole kidney modeling with chemotherapy. Partial kidney modeling from 439 survivors who received RT (median age, 7.3 years) demonstrated 5 or 10 Gy to 100% kidney gave a <5% risk of grades 3 to 5 toxicity with 1500 mg/m2 carboplatin or no chemo. With 480 mg/m2 cisplatin, a 3% risk of ≥grade 3 toxicity occurred without RT and a 5% risk when 26% kidney received ≥10 Gy. With 63 g/m2 of ifosfamide, a 5% risk of ≥grade 3 toxicity occurred with no RT, and a 10% toxicity risk occurred when 42% kidney received ≥10 Gy.

CONCLUSIONS

In patients with Wilms tumor, the risk of toxicity from 10.5 Gy of WAI is low. For 12 Gy fractionated TBI with various mixtures of chemotherapy, the risk of severe toxicity is low, but low-grade toxicity is not uncommon. Partial kidney data are limited and toxicity is associated heavily with the use of nephrotoxic chemotherapeutic agents. Our efforts demonstrate the need for improved data gathering, systematic follow-up, and reporting in future clinical studies. Current radiation dose used for Wilms tumor and TBI appear to be safe; however, efforts in effective kidney-sparing TBI and WAI regimens may reduce the risks of renal injury without compromising cure.

Evaluation of Diaphragm Position Variations During Proton Therapy for Pediatric Patients With Neuroblastoma

Background To evaluate the respiratory-induced intrafractional diaphragm motion and interfractional diaphragm displacement in pediatric patients with neuroblastoma (NBL). Materials and methods Ten pediatric patients with a mean age of 4.5 years (range: 1.8-8.7 years) with abdominal NBL treated with proton therapy (PT) have been evaluated. Intrafractional motion and interfractional displacement have been analyzed by using cine radiography and orthogonal X-ray images, respectively. In each case, the cranio-caudal positions of the diaphragm have been measured as an index. This study has investigated the possible correlations between intrafractional diaphragm motion and height. Additionally, interfractional displacement and its time trend during the treatment course have been analyzed. Results The average right and left diaphragm intrafractional motions of 8.3 mm (range: 4.4-11.5 mm) and 6.4 mm (range: 2.2-11.8 mm) were observed, respectively; however, no significant correlation has been observed with height. An interfractional displacement of 5 mm or more has been observed in 20 out of 152 fractions (13%). The average absolute value of the interfractional displacement was 2.5 mm (range: 0-8.6 mm). Interfractional displacement did not show a peculiar tendency throughout the treatment period. Conclusions It was suggested that respiratory-induced diaphragm position variation in children varies greatly among individuals, and accurately estimating it based on height is difficult. Thus, these individual evaluations are considered indispensable.

Paediatric radiation therapy without anaesthesia - Are the children moving?

PURPOSE

Children who require radiation therapy (RT) should ideally be treated awake, without anaesthesia, if possible. Audiovisual distraction is a known method to facilitate awake treatment, but its effectiveness at keeping children from moving during treatment is not known. The aim of this study was to evaluate intrafraction movement of children receiving RT while awake.

METHODS

In this prospective study, we measured the intrafraction movement of children undergoing treatment with fractionated RT, using pre- and post-RT cone beam CT (CBCT) with image matching on bony anatomy. Study CBCTs were acquired at first fraction, weekly during RT, and at last fraction. The primary endpoint was the magnitude of vector change between the pre- and post-RT scans. Our hypothesis was that 90 % of CBCT acquisitions would have minimal movement, defined as <3 mm for head-and-neck (HN) treatments and <5 mm for non-HN treatments.

RESULTS

A total of 65 children were enrolled and had evaluable data across 302 treatments with CBCT acquisitions. Median age was 11 years (range, 2-18; 1st and 3rd quartiles 7 and 14 years, respectively). Minimal movement was observed in 99.4 % of HN treatments and 97.2 % of non-HN treatments. The study hypothesis of >90 % of evaluations having minimal movement was met. Children who were age >11 years moved less at initial evaluation but tended to move more as a course of radiation progressed, as compared to children who were younger.

CONCLUSION

Children receiving RT with audiovisual distraction while awake had small magnitudes of observed intrafraction movement, with minimal movement in >97 % of observed RT fractions. This study validates methods of anaesthesia avoidance using audiovisual distraction for selected children.

The Feasibility of Implementing Deep Inspiration Breath-Hold for Pediatric Radiation Therapy

PURPOSE

Radiation therapy delivery during deep inspiration breath-hold (DIBH) reduces the irradiation of the heart and lungs and is therefore recommended for adults with mediastinal lymphoma. However, no studies have addressed the use of DIBH in children. This pilot study investigates the feasibility of and compliance with DIBH in children.

METHODS AND MATERIALS

Children from the age of 5 years were recruited to a training session to assess their ability to perform DIBH. No children received radiation therapy. The children were placed in a potential radiation therapy position. The DIBH was voluntary and monitored using an optical surface system providing visual feedback. Children who performed 3 stable DIBHs of 20 seconds each and remained motionless were deemed DIBH compliant. Compliance, equipment suitability, and coaching were further assessed in a semistructured interview.

RESULTS

We included 33 children (18 healthy and 15 hospitalized children with cancer) with a mean age of 8.5 years (range, 5-15). A total of 28 (85%) children were DIBH compliant. Twenty children were deemed immediately DIBH compliant, and 8 were deemed conditionally DIBH compliant, as DIBH compliance was presumed with custom-made immobilization and/or additional DIBH training. Mean age of the DIBH-compliant and the non-DIBH-compliant children was 8.9 years (range, 5-15) and 6 years (range, 5-9), respectively. Only 1 of 15 hospitalized children was not DIBH compliant and only 1 of all 33 children was unable to grasp the DIBH concept. The available DIBH equipment was suitable for children, and 94% reported that they were happy with training and performing DIBH.

CONCLUSIONS

This pilot study demonstrated that children from the age of 5 years can potentially comply with the DIBH technique and perform stable and reproducible DIBHs suitable for radiation therapy. Custom-made immobilization and adequate training will potentially increase DIBH compliance. A prospective clinical trial (NCT03315546), investigating the dosimetric benefit of radiation therapy delivery in DIBH compared with free breathing with pediatric patients, has been initiated.