Dosimetric and clinical outcomes of CT based HRCTV delineation for HDR intracavitary brachytherapy in carcinoma cervix — a retrospective study

Background: Brachytherapy for carcinoma cervix has moved from Point A based planning to optimization of dose based on HR-CTV. Guidelines have been published by GEC ESTRO on HR-CTV delineation based on clinical gynecological examination and MR sequences. These have given significant clinical results in terms of local control. However, many centers around the country and worldwide still use CT based planning, which restricts HR-CTV delineation, as disease and cervix can rarely be differentiated on a planning CT. Various studies have been done to develop CT based contouring guidelines from the available data, but enough evidence is not available on the clinical outcome when treatment is optimized to HR-CTV contoured on CT images. The purpose of this study is to find out the relation between local control and dosimetry of HR-CTV as delineated on CT images. Materials and methods: Patients of locally advanced carcinoma cervix treated radically with EBRT of 50 Gy in 25# and at least 4 cycles of concurrent weekly Cisplatin having a complete or partial response to EBRT were taken for study. All patients had  completed CT based Intracavitary brachytherapy to 21 Gy in 3# of 7 Gy per # with dose prescription at point A and optimizing dose to reduce bladder and rectal toxicity. Follow up data on locoregional recurrence was obtained. HR-CTV delineation was done retrospectively on the treatment plan following guidelines by Viswanathan et al. EQD2 doses for EBRT+BT were calculated for point A and HR-CTV D90. The dosimetric data to HR-CTV and to Point A were then compared with patients with locoregional control and with local recurrence. Results: 48 patients were taken, all had squamous cell carcinoma. The median age was 48 years. 33.33% were stage IIA, the rest were stage IIB. Median follow-up was 30 months with 25% developing recurrence of the disease. HR-CTV D90 EQD2 dose was significantly higher in patients with locoregionally controlled disease than in patients with local recurrence (83.97 Gy10 vs. 77.96 Gy10, p = 0.002). Patients with HR-CTV D90 EQD2 dose greater than or equal to 79.75 Gy10 had better locoregional control than patients receiving dose less than 79.75 Gy10 (p = 0.015). Kaplan Meier plot for PFS showed significantly improved PFS for patients receiving HR-CTV D90 dose of at least 79.75 Gy10 (log-rank p-value = 0.007). Three year progression free survival was 87.1% in patients receiving HR-CTV D90 dose of at least 79.75 Gy10. Conclusion: CT based HR -CTV volume delineation with the help of pre brachytherapy clinical diagrams and MRI imaging may be feasible in a select subgroup of patients with complete or near-complete response to external beam radiation

Comparison of twice weekly palliative RT versus continuous hypofractionated palliative RT for painful bone metastases

Background: Palliative hypofractionated radiotherapy (RT) is an effective mode of treating painful bone metastasis. While 8 Gy single fraction radiation is often effective for the same, for complicated bone metastases a protracted fractionated regimen is preferred, of which 30 Gy/10#/2weeks or 20 Gy/5#/1 week are the most common worldwide. However such schedules add to the burden of already overburdened radiation treatment facilities in a busy center, wherein alternative logistic favourable schedules with treatment on weekends are preferred. Here we compare the efficacy of a twice weekly schedule to that of standard continuous 20 Gy/5 #/1 week schedule in terms of pain relief, response and quality of life. Materials and methods: A prospective non randomized study was undertaken from Jan 2018 to May 2019, wherein eligible patients of complicated bone metastases received palliative radiotherapy of 20 Gy/5#, either continuously for 5 fractions from Monday to Saturday or twice weekly, Saturday and Wednesday, starting on a Saturday over about 2 weeks. Pain relief was assessed by the Visual Analogue Scale (VAS) and FACES pain scale recorded prior to starting palliative RT and at 4, 12 and 16 weeks. Results: Thirteen patients received continuous Hypofractionated RT while 16 received it in a twice weekly schedule. Spine was the most common site receiving palliative Radiation (27/29), while breast cancer was the most common primary (16/29). The demographic and the baseline characteristics were comparable. The mean pain score decline at 4 weeks was 2.56 ±1.1 and 2.71 ± 0.52 in the 5-day and the two-week schedule, respectively (p = 0.67). Conclusion: A twice weekly schedule over about two weeks was found to be equivalent in pain control and response to the standard fractionated palliative radiation and, thus, can be safely employed in resource constrained, busy radiotherapy centers

Pattern of locoregional failure in postoperative cases of locally advanced carcinoma of buccal mucosa treated with unilateral versus bilateral neck radiation: lesson learned from a basic practice setup

Background: Carcinoma of buccal mucosa forms a sizeable percentage of the diagnosed oral cavity cancers in India. There is limited data on elective treatment of the contralateral neck for well-lateralized carcinoma with no involved nodes in the contralateral neck. We conducted this study to compare locoregional control in patients treated with unilateral vs. bilateral neck irradiation. Materials and methods: 48 patients with carcinoma of buccal mucosa were selected. Patients were divided into unilateral and bilateral arms based on radiation treatment of the ipsilateral or bilateral neck. All patients received adjuvant radiation with Cobalt 60 unit. Patient-specific and follow-up data were collected from records and dosimetric data from TPS. Chi-square and unpaired t-test was used to compare data between arms and Kaplan Meier plot; Cox regression was used for survival analysis. Results: After a median follow-up of 23 months, 15 (31.3%) patients had developed disease recurrence, 8 and 7 in the unilateral and bilateral arms, respectively (p = 0.591). There was no contralateral neck failure during the follow-up period. The 2-year disease-free survival was 68.2% and 72.2% in the unilateral and bilateral arms, respectively. Among risk factors for disease recurrence, Depth of Invasion, delay in starting radiation and PTV coverage were significant contributing factors. Cox multivariate regression suggested DOI and delay in starting radiation to be significant prognostic factors for DFS. Conclusion: Bilateral neck radiation does not provide any advantage over ipsilateral neck radiation for properly selected well lateralized buccal mucosal squamous cell carcinoma. Ipsilateral neck radiation facilitates better sparing of organs at risk