Dosimetric Impact of Air Pockets in the Vaginal Cuff Brachytherapy Using Model-based Dose Calculation Algorithm.

Background: Endometrial cancer is the most common disease of the female reproductive system. Vaginal cuff brachytherapy (VCB) has intrinsic advantages compared to external beam therapy when treated with radiation. A single-channel cylinder is a standard applicator in VCB. The present study aims to estimate a change in the dose to vaginal mucosa due to air pockets between the cylinder and vaginal mucosa by calculating with the Acuros BV algorithm and comparing it to the Task Group 43 (TG-43) algorithm. Materials and Methods: Patients who presented with air packets were included retrospectively. For each patient, three plans were created: the first plan used TG-43, the second plan used dose recalculation with Acuros BV, and the third plan was generated by re-optimization by Acuros BV. On the same axial computed tomography image, the point doses at the cylinder's surface and the displaced mucosa were recorded and the ratios were then estimated. Results: The average volume of air pockets was 0.08 cc (range of 0.01-0.3 cc), and 84% of air pockets displaced the vaginal mucosa by ≥0.2 cm. The average ratios of dose were 0.77 ± 0.09 (1 standard deviation [SD]) and 0.78 ± 0.09 (1 SD) for TG-43 and Acuros BV algorithms, respectively. Due to the air pocket, mucosa received a reduced dose by an average of 22.72% and an average of 23.29% for TG-43 and Acuros BV, respectively. The maximum displacement of mucosa and the ratio of doses were negatively correlated for both. In the Optimized Acuros BV plan, total dwell time increased by 1.8% but no considerable change in the dose ratios. Conclusion: The calculated dose of mucous membrane forced out of the cylinder surface by air pockets by the Acuros BV algorithm was nonsignificantly different from TG-43. Therefore, even in the presence of air pockets, the TG-43 algorithm for calculating the VCB dose is appropriate.

Mucoepidermoid Carcinoma of the Salivary Gland: Long Term Outcomes from a Tertiary Cancer Center in India.

To analyze the patterns of failure and factors affecting recurrence and overall survival in mucoepidermoid carcinoma of the salivary gland. The hospital records were retrospectively analyzed from October 2010 to January 2016. Patients diagnosed as mucoepidermoid carcinoma of the salivary gland were eligible for analysis. All patients received surgery as the primary treatment modality with or without post operative radiotherapy. Statistical analysis for factors affecting recurrence was done by cox regression analysis and p value less than 0.05 was considered significant. A total of 116 patients were diagnosed to have malignant salivary gland tumors of which 69 were mucoepidermoid carcinomas (69.5%). The median age was 43 years (8-75 years). Majority of the tumors occurred in major salivary glands gland (77%). 51% patients were females. Most common stage was stage II (36%) followed by stage I (27.5%), stage IV (20.3%) and stage III (16%). High grade carcinomas comprised 34.8%, intermediate grade 30.4% and low grade 34.8%. 36 patients (52.2%) received adjuvant radiotherapy (60 Gy in 30 fractions). At a median follow up of 42 months (8-70 months), 8 (11.6%) patients died (7 cancer related and 1 noncancer related). The locoregional recurrence rate was 4.3% whereas the distant metastasis rate was 11.6%. Most common site of distant metastasis was lung. The mean disease free survival time was 61.4 months and the mean overall survival was 62 months. On univariate analysis, age < 50 years, node positive, presence of PNI, high grade, presence of LVI and local recurrence were significant factors for distant metastasis (p < 0.05). On multivariate analysis, high grade, presence of LVI and local recurrence were significant factors for distant metastasis (p < 0.05). Mucoepidermoid carcinomas of salivary gland have good long term local control and overall survival. Majority of the recurrences are distant metastasis. High grade, LVI and local recurrence are significant risk factors for distant relapse.

Incidental radiation dose to internal mammary lymph nodal area in carcinoma breast patients treated with forward planning intensity-modulated radiation therapy technique: A single-institute dosimetric study.

INTRODUCTION: Breast cancer (BC) is the most common cancer in Indian females. The irradiation of internal mammary lymph nodal area (IMLN) is recommended by latest guidelines and literature, even in patients with N1 nodal disease, but it is not routinely done in many institutes due to the risk of late lung and heart toxicities. The incidence of isolated IMLN recurrence <1%. The incidental radiation therapy (RT) dose to axillary lymph nodal area (ALN) could result in lower local recurrences according to literature. The aim of this study is to assess the incidental IMLN area RT dose in patients treated with forward planning intensity-modulated RT (FIF-IMRT). MATERIALS AND METHODS: The aim of our study is to evaluate the RT dose received by IMLN area incidentally in FIF-IMRT and is a single-institute dosimetric study. The patients planned for RT after breast conservation surgery (BCS) or modified radical mastectomy (MRM) were evaluated for IMLN incidental dose. RESULTS: The mean doses to IMLN area (Dmean) were comparable to literature for both BCS and MRM patients. All other dose parameters (D95, D90) in our study were slightly lower but comparable to literature for the FIF-IMRT planning. Interestingly, the incidental IMLN RT doses in our study are in the same range as the incidental ALN RT doses studied in the literature (48%-68%). CONCLUSION: The IMLN area receives a major amount of incidental radiation dose during conformal RT by FIF-IMRT and higher doses for MRM than BCS. This RT dose is not in the therapeutic range but is comparable to the incidental dose to ALN area reported in the literature.

Carcinoma vulva patterns of recurrence and treatment outcomes: A single-institution experience.

AIM: The aim of this study was to evaluate the patterns of recurrence and outcomes in patients with vulvar cancer treated with surgery, with or without postoperative radiotherapy (RT) or RT alone. MATERIALS AND METHODS: The hospital records were retrospectively analyzed from February 2007 to May 2016. All patients that had biopsy-proven carcinoma vulva were included for analysis. Surgery was done by simple or radical vulvectomy with or without lymph node dissection. Radical RT dose was 60 Gy (photons alone or with electron boost). Adjuvant RT was administered in case of node positivity or positive margins. RESULTS: A total of 76 patients were diagnosed as squamous cell carcinoma of vulva. The median age was 59 years. About 59 patients were treated by surgery and 17 patients were treated by radical RT. The most common stage was IB. Adjuvant RT was administered in 10 patients. About 13 patients (22%) underwent inguinal lymphadenectomy. At a median follow-up of 35 months, 49 patients (64.4%) were alive, 27 died, and 6 patients were lost to follow-up. Locoregional recurrence rate was 24.5% in radical surgery group, 12% in surgery plus adjuvant RT group, and 47% in radical RT group. Distant metastasis rate was 4%. The progression-free survival at 3 years was 45.3% and 35.5% in the surgery group and radical RT group, respectively. CONCLUSION: Surgery resulted in favorable local control rates in early-stage carcinoma vulva. Adjuvant RT is indicated in case of nodal positivity or positive margins. Radical RT can be considered as an alternative in patients with comorbidities.

A Dosimetric Analysis of the Rectal Doses in Intracavitary Brachytherapy of Carcinoma Cervix: A Prospective Study from a Single Institute.

INTRODUCTION: Carcinoma cervix is a common gynecologic malignancy in India and is treated with radical chemoradiation where intracavitary brachytherapy (ICR) is an integral part. In ICR of cervix, the two-dimensional (2D) point-based dosimetry cervix is the most common method used in high-volume centers with rectal dose calculation at modified ICRU rectal point with rectal wire placement. The rectal dose measurement using this method underestimates the dose to the rectum, and rectal dose also varies with the type of applicator used. The aim of our study is to compare the rectal dose calculated by ICRU 38 method versus rectal dose calculated by the rectal wire method using Henschke applicator. MATERIALS AND METHODS: This is a single-institute, dosimetric comparison study done prospectively. Fifty patients were planned for ICR after 2D orthogonal radiograph-based, computer planning by iridium 192 high-dose rate remote afterloading technique after placing the appropriate Henschke applicator. The vaginal packing was done using sterile gauze with contrast material for defining the ICRU 38 rectal point, and a rectal wire was placed for the modified ICRU rectal point. Rectal doses were calculated by both the methods and compared. RESULTS: The modified ICRU rectal point recorded a lower rectal dose (mean of 25%) compared to ICRU 38 rectal point in the study patients. There were ten patients (20%) with either too much or too little contrast material which made the visualization of the rectal point and radiation planning difficult. P value by paired t-test method was 0.0001, which was statistically significant. CONCLUSION: The modified ICRU rectal point is easier to visualize than ICRU 38 method (100% vs. 80%) for dosimetry, but it underestimates the rectal doses when compared to ICRU 38 rectal point. There needs to be a correction factor applied (25% in our study for Henschke applicator) when evaluating the rectal doses calculated by rectal wire method, to reduce the rectal toxicity.

High-dose-rate interstitial brachytherapy in oral cancer-Its impact on quality of life.

PURPOSE: The aim of the study was to assess the impact of high-dose-rate (HDR) interstitial brachytherapy on quality of life (QOL) in oral cancer. METHODS AND MATERIALS: Thirty-two patients of oral cancer treated at our institute from January 2010 to December 2014 with radical radiotherapy (external beam radiotherapy + brachytherapy) were included for analysis; 30 patients received external beam radiotherapy (50-54 Gy) and HDR brachytherapy boost (18-24.5 Gy); 2 patients received radical HDR brachytherapy (31.5 Gy). Quality of life (QOL) was assessed by Telugu, Hindi, and English versions of EORTC Quality of Life Core-30 and EORTC Quality of Life Head and Neck Module (QLQ H&N35) before treatment, at 3 months, 6 months, 1 year, and 2 years after treatment. RESULTS: Of the 32 patients, 2 patients died and 1 patient progressed on followup; 2 patients were re-irradiation cases. On excluding these cases, 27 patients were available for analysis. The followup duration was 6-55 months. At the time of analysis, 91% (29) patients were disease free, 3% (1) progressed, and 6% (2) died. At the end of 2 years, none of the QLQ-C30 functional scores fell below the baseline. Pain, swallowing, sensory, speech, social contact, and social eating worsened at 3 months but improved over 2 years (p < 0.001). Sexuality and financial status showed delayed improvement (p < 0.001). Among the head and neck parameters, dry mouth and sticky saliva were significant determinants of QOL with delayed improvement (p < 0.001). The impact of age, sex, and tumor stage and on QOL was analyzed. Women reported a poorer QOL for physical and emotional parameters, social eating, weight loss, and fatigue. Tumor stage significantly affected QOL, with early stages showing a better QOL. CONCLUSIONS: Almost all patients regained normal function after treatment and reported an excellent QOL at 2 years. However, tumor stage significantly affected the QOL.

Study of positional dependence of dose to bladder, pelvic wall and rectal points in High-Dose-Rate Brachytherapy in cervical cancer patients.

The objective of the study is to examine the variation in doses to, Bladder, pelvic wall and Rectal Points when a patient is simulated in Supine (S Position) and Lithotomy M shaped positions (LM Position), respectively as part of Intracavitary Brachytherapy in Cervical Cancer patients. Patients (n = 19) were simulated and orthogonal images were taken in S Position and LM Positions on a physical simulator. Digital orthogonal X-ray images were transferred to Brachyvision Treatment Planning System via Dicom to generate treatment plans. Radio opaque dye of 7 ml was injected into the Foley bulb for identification and digitization of International Commission on Radiological Units and Measurements (ICRU) Bladder point. Pelvic side wall points were marked in accordance with ICRU 38 recommendations. A Rectal tube containing dummy source marker wire was used to identify Rectal Point. Students't-test was used to analyze the results. Doses in LM Position were lower and statistically significant when compared to S Position for ICRU Bladder Point, pelvic walls and Rectal Point. It was observed that movement of applicator could be the reason for the variations in doses between the two positions. Bladder, pelvic wall and rectal points systematically registered lower doses in LM Position as compared to S Position.