Can knowledge based treatment planning of VMAT for post-mastectomy locoregional radiotherapy involving internal mammary chain and supraclavicular fossa improve performance efficiency?

Introduction: To validate and evaluate the performance of knowledge-based treatment planning for Volumetric Modulated Arc Radiotherapy for post-mastectomy loco-regional radiotherapy. Material and methods: Two knowledge-based planning (KBP) models for different dose prescriptions were built using the Eclipse RapidPlanTM v 16.1 (Varian Medical Systems, Palo Alto, USA) utilising the plans of previously treated patients with left-sided breast cancer who had undergone irradiation of the left chest wall, internal mammary nodal (IMN) region and supra-clavicular fossa (SCF). Plans of 60 and 73 patients were used to generate the KBP models for the prescriptions of 40 Gy in 15 fractions and 26 Gy in 5 fractions, respectively. A blinded review of all the clinical plans (CLI) and KBPs was done by two experienced radiation oncology consultants. Statistical analysis of the two groups was also done using the standard two-tailed paired t-test or Wilcoxon signed rank test, and p<0.05 was considered significant. Results: A total of 20 metrics were compared. The KBPs were found to be either better (6/20) or comparable (10/20) to the CLIs for both the regimens. Dose to heart, contralateral breast,contralateral lung were either better or comparable in the KBP plans except of ipsilateral lung. Mean dose (Gy) for the ipsilateral lung are significantly (p˂0.001) higher in KBP though the values were acceptable clinically. Plans were of similar quality as per the result of the blinded review which was conducted by slice-by-slice evaluation of dose distribution for target coverage, overdose volume and dose to the OARs. However, it was also observed that treatment times in terms of monitoring units (MUs) and complexity indices are more in CLIs as compared with KBPs (p<0.001). Discussion: KBP models for left-sided post-mastectomy loco-regional radiotherapy were developed and validated for clinical use. These models improved the efficiency of treatment delivery as well as work flow for VMAT planning involving both moderately hypo fractionated and ultra-hypo fractionated radiotherapy regimens.

Dose-Escalated Intensity-Modulated Radiotherapy for the Management of Locally Advanced Cervical Cancer.

Objective In this study, we aimed to assess the response and toxicity related to dose escalation in external beam radiation therapy (EBRT) using intensity-modulated radiation therapy (IMRT) with weekly concurrent cisplatin followed by de-escalated brachytherapy (BT) in locally advanced carcinoma cervix of International Federation of Gynecology and Obstetrics (FIGO) 2018 stage IIB-IIIC1. Materials and methods Fifty-two patients diagnosed with cervical cancer FIGO 2018 stage IIB-IIIC1 were treated with curative intent from November 2019 to October 2021. The dose of 50 Gy was prescribed for the primary tumor volume and elective pelvic nodal volume followed by a primary boost to a dose of 20 Gy. Gross lymph node (LN) of size >1 cm after EBRT completion received a sequential nodal boost of 10 Gy. All patients received concurrent cisplatin to a dose of 40 mg/m2 for a total of five to six weekly cycles. All patients received two fractions of BT to a dose of 6 Gy after EBRT completion. Radiation-induced acute toxicities were graded according to the Radiation Therapy Oncology Group (RTOG) criteria and hematologic toxicity was graded according to the Common Terminology Criteria for Adverse Events (CTCAE v4.0). Results A median follow-up of six months was available for the 40 eligible patients. All patients tolerated treatment with an acceptable toxicity profile. Grade III dermatitis, grade III gastrointestinal (GI) toxicity, and grade III genitourinary (GU) toxicity were seen in three (7.5%), six (17.5%), and three patients (7.5%) respectively. Grade I anemia was evident in all patients. At six months after EBRT completion, 37 patients (92.5%) had a complete response and only three patients (7.5%) had residual disease. Conclusion Based on our findings, patients with cervical cancer treated with dose-escalated IMRT have a satisfactory outcome with reasonably low levels of treatment-related acute GI and GU toxicities. The findings of the present study endorse the notion that the application of a high dose of external radiation to the pelvis by IMRT technique with image-guided delivery could be an acceptable alternative to the standard-dose management schedule.

Trimodality treatment in malignant pleural mesothelioma - Ordeal or real deal?

BACKGROUND: Management of MPM is complex and controversial as there is a paucity of good quality evidence. We report the toxicity and outcomes in patients who received trimodality treatment for non-metastatic MPM at our institution. METHODS & MATERIALS: We reviewed the electronic medical records of surgically managed MPM patients at our institution in the last decade. Dosimetric parameters of target volume and organs at risk were documented by the treatment planning workstation. SPSS was used for statistical analysis. RESULTS: Between January 2008 and October 2018, 21 patients underwent surgery for MPM - all but 2 patients underwent extra-pleural pneumonectomy (EPP); epithelioid MPM was the most common histology. All patients, except 2, received neoadjuvant Pemetrexed/platinum doublet chemotherapy. Fourteen patients received adjuvant hemithoracic RT; ten patients were treated with a conformal technique at our institute and dosimetric data was available for analysis. Average time to start RT after surgery was 51 days (range 32-82 days). All patients were treated with a conformal technique using IMRT/VMAT to a dose of 45Gy in 25 fractions. Mean overall RT duration was 35 days (range 30-42 days). Grade I/II Pneumonitis was seen in 4 patients. One patient developed grade III acute lung toxicity unrelated to RT. At a median follow up of 25 months, 8 patients had died, of whom six died due to the disease and two died in the immediate post op period. Two-year DFS and OS were 58% and 73%, respectively. CONCLUSION: In spite of the extensive surgery and complex hemithoracic RT, we demonstrated excellent dosimetry, toxicity profile and favorable outcomes in non-metastatic MPM.