Analgesic radiation therapy for bone metastasis in Dakar

Background: Three-dimensional conformal radiotherapy is a new tool in the Senegalese therapeutic arsenal. Symptomatic bone metastases affect the quality of life of patients. Analgesic radiotherapy is proposed to patients to relieve them. Patients and methods: A prospective descriptive study was carried out on all patients with symptomatic bone metastasis. Hypo-fractionated radiotherapy was performed on the painful site. The visual analogue scale was used to assess pain before radiotherapy, 72 hours and one week after. Results: The sex ratio was 0.5. The median age at diagnosis of symptomatic metastasis was 53 years. All patients received 8 Gy (Gray) in one session. A complete response was noted one week post radiotherapy. Conclusion: Analgesic radiotherapy improves the quality of life of patients with symptomatic bone metastasis.

Brainstem intraparenchymal schwannoma with genetic analysis: a case report and literature review

Background Schwannomas are neoplasms that typically arise from the myelin sheath of peripheral nerves and rarely originate within the brain parenchyma. Some case reports present schwannomas arising from the brainstem, but regrowth of the tumor and the efficacy of postoperative irradiation have not been examined. In addition, the genetic background of schwannomas arising from the brainstem has not been investigated. Case presentation A 21-year-old male presented with diplopia, dysphagia, and left-sided hemiparesis, dysesthesia, and ataxia. Intracranial imaging showed a heterogeneous mass with a cystic lesion in the pontomedullary junction. Since the tumor caused obstructive hydrocephalus, the patient underwent subtotal tumor resection. A histopathologic evaluation aided a diagnosis of brainstem intraparenchymal schwannoma. Gradual postoperative mass regrowth was recognized. Three-dimensional conformal radiotherapy was performed on the residual mass and surgical cavity. No tumor regrowth was observed 4 years after surgery. To investigate the genetic background of the tumor, target sequences for 36 genes, including NF2, SMARCB1, and LZTR1, and microsatellite analysis for loss of 22q did not show any somatic variants or 22q loss. Conclusions We suggest that brainstem schwannomas might differ from conventional schwannomas in their genetic background.

Dosimetric study on the use of Eclipse beam angle optimiser for conformal planning

Aim: The aim of this study was to evaluate the use of Eclipse’s beam angle optimiser (BAO) for three-dimensional conformal radiotherapy planning. Materials and methods: Eleven 3D conformal lung plans, with varied tumour volumes, were retrospectively studied. For each clinical plan, a BAO plan was produced and then optimised by an experienced planner. Plan quality was assessed using International Commission on Radiation Units and Measurements (ICRU)-83 and Radiation Therapy Oncology Group (RTOG) recommended dose reporting metrics for dose volume prescribing and reporting. Results: Differences in dose volume histograms for both methods showed no clinical significance. Planning target volume Dmax for both plans was comparable and within ICRU guidelines. Reported spinal cord Dmax and the doses to 33% and 67% volume of the heart were within the RTOG recommended limits. Mean lung V20 values for BAO and non-BAO plans were 20 and 16%, respectively. The average monitor units for the BAO plans were about 11% lower. The conformity and homogeneity indices were within the acceptable range for both cases. On average, it took 23 minutes to plan using the BAO compared to 68 minutes for the non-BAO plans. Conclusion: Eclipse BAO shows the potential to produce good quality conformal plans and reduce planning time. This process could be further refined with multi-leaf collimator and optimal collimator angle options.

Comparison of Dosimetric Parameters of Three-Dimensional Conformal Radiotherapy and Intensity-Modulated Radiotherapy in Breast Cancer Patients Undergoing Adjuvant Radiotherapy after Modified Radical Mastectomy

Introduction Adjuvant radiotherapy has an important role in preventing locoregional recurrences. But radiation-induced late sequelae have become an important area of concern. The ideal postmastectomy radiotherapy technique is an area of controversy. The present study was designed to compare two widely practiced conformal techniques, three-dimensional conformal radiotherapy (3DCRT) and intensity-modulated radiotherapy (IMRT), in terms of dosimetry. Material and Methods A total of 50 postmodified radical mastectomy patients were selected and were randomized to treatment either by 3DCRT or IMRT technique. Two opposing tangential beams were used in 3DCRT plans whereas five to seven tangential beams were used for IMRT plans. The prescribed dose was 50 Gy in 25 fractions over 5 weeks. The dosimetric parameters were compared for planning target volume (PTV), lungs, heart, and left ventricle, opposite breast and esophagus. Results The dosimetric parameters of PTV in terms of D95%, D90%, D50%, and Dmean showed no significant difference among both techniques. The IMRT technique had significantly better mean values of Dnear-min/D98% (45.56 vs. 37.92 Gy; p = 0.01) and Dnear-max/D2% (51.47 vs. 53.65 Gy; p < 0.001). Also, conformity index (1.07 vs. 1.29; p = 0.004) and homogeneity index (0.22 vs. 0.46; p = 0.003) were significantly better in IMRT arm.The dosimetric parameters of ipsilateral lung were significantly higher in IMRT arm in terms of mean dose (19.92 vs. 14.69 Gy; p < 0.001) and low/medium dose regions (V5, V10, V13, V15, V20; p < 0.05). However, high-dose regions (V40) were significantly higher in 3DCRT arm (15.57 vs. 19.89 Gy; p = 0.02). In contralateral lung also, mean dose was significantly higher in IMRT technique (3.63 vs. 0.53 Gy; p < 0.0001) along with low-dose regions (V5, V10, V13, V15; p < 0.05) while V20 was comparable between both the arms.In left-sided patients, the heart dose favored 3DCRT technique in terms of mean dose (17.33 vs. 8.51 Gy; p = 0.003), low/medium dose regions (V5, V10, V20; p < 0.05), and doses to partial/whole volumes (D33, D67, D100). But the high-dose regions (V25, V30, V40) were comparable between both the arms. The dosimetry of left ventricle also showed significantly lesser values of mean dose and V5 in 3DCRT technique (p < 0.0001).The opposite breast also showed higher mean dose with IMRT technique (2.60 vs. 1.47 Gy; p = 0.009) along with higher V5 (11.60 vs. 3.83 Gy; p = 0.001). The dosimetric parameters of esophagus showed higher mean dose in IMRT technique (10.04 vs. 3.24 Gy; p < 0.0001) but the high-dose regions V35 and V50 were comparable between both the arms. Conclusion A clear advantage could not be demonstrated with any of the techniques. The IMRT technique led to more conformal and homogenous dose distribution with reduction in high-dose regions in ipsilateral lung while the 3DCRT technique showed lesser mean dose to organs at risk (OARs). The exposure of large volumes of OARs to low doses in IMRT technique may translate to increased long-term radiation-induced complications. The shortcomings of 3DCRT technique can be overcome by using multiple subfields within tangential fields.

Radiation-induced acute injury of intensity-modulated radiotherapy versus three-dimensional conformal radiotherapy in induction chemotherapy followed by concurrent chemoradiotherapy for locoregionally advanced nasopharyngeal carcinoma: a prospective cohort study

To address whether the addition of intensity-modulated radiotherapy (IMRT) compared to three-dimensional conformal radiotherapy (3D-CRT) aggravate radiation-induced acute injury of locoregionally advanced nasopharyngeal carcinoma (LANPC) patients with induction chemotherapy (IC) followed by concurrent chemoradiotherapy (CCRT). We conducted a prospective study of 182 patients in the stage III to IVb with biopsy-proven nonmetastatic LANPC who newly underwent radiotherapy and sequentially received IC, followed by CCRT at our institution. Occurring time of radiation-induced toxicities were estimated and compared using the Kaplan–Meier method and Log-rank test. The most severe acute toxicities included oral mucositis in 97.25% and dermatitis in 90.11%. Subset analysis revealed that Grade 3–4 acute dermatitis were significantly higher in the IMRT than 3D-CRT. Oral mucositis and dermatitis were the earliest occurrence of acute injuries (2 years: 60.44% and 17.58%). Patients in IMRT group achieved significantly lower risk of bone marrow toxicity, but higher risk of leukopenia and gastrointestinal injury. Multivariate analyses also demonstrated that IMRT, female gender and hepatitis were the independent prognostic factors for bone marrow toxicity. In a combined regimen of IC followed by CCRT for the treatment of LANPC, IMRT seems to be an aggressive technique with a trend towards increased gastrointestinal and hematological toxicities, but decreased bone marrow toxicity than those treated with 3D-CRT. This study provides a comprehensive summary of prospective evidence reporting the side effects in the management of LANPC patients. We quantify the occurrence risks of chemoradiotherapy-induced acute injuries through analysis of time-to-event.