Equivalent dose in 2 Gy (EQD2) to pelvic lymph nodes using volume based prescription for three brachytherapy applicators - a dosimetric retrospective analysis.

BACKGROUND: Pelvic lymph node (PLN) metastasis has been included in the FIGO staging, so there is a need to determine the dose contribution from brachytherapy to ascertain the total delivered dose to the pelvic lymph nodes in cervical cancer. The aim of the study was to calculate the equivalent dose in 2 Gy (EQD2) of the pelvic lymph nodes (PLNs) based on volume prescription using three applicators. MATERIALS AND METHODS: Forty-one patients who had undergone external beam radiotherapy followed by brachytherapy using tandem ovoids (TO), tandem ring (TR) and TO + free hand interstitial needles (TO + FH) applicators were taken for this study. 26 Gy in 4 fractions was prescribed to HRCTV. The external iliac node (ELN), internal iliac node (ILN) and obturator (OBT) were contoured and the median EQD2 of the lymph nodes was calculated. RESULTS: The median bilateral EQD2 values of ELN were 1.55 Gy (TR), 1.75 Gy (TO), 1.9 Gy (TO + FH), of ILN these were 2.57 Gy (TR), 3.27 Gy (TO), 3.04 Gy (TO + FH), and of OBT these were 3.69 Gy (TR), 4.46 Gy (TO), 4.69 Gy (TO + FH), respectively. The total median EQD2 values of TR, TO and TO + FH were 52.71 Gy, 53.03 Gy, and 53.88-62.73 Gy, respectively. CONCLUSION: Our study calculated the median EQD2 to the pelvic lymph nodes using three types of applicators in brachytherapy. This could serve as reference to decide on the EBRT boost dose while treating patients with enlarged pelvic lymph nodes.

Correlation of planning target volume with mucositis for head-and-neck cancer patients undergoing chemoradiation.

CONTEXT: Head-and-neck cancer patients undergoing chemoradiation. AIMS: The aim of the study was to see if there is any correlation between the planning target volume (PTV) and mucositis. SETTINGS AND DESIGN: This was a single-arm prospective study. SUBJECTS AND METHODS: A total of forty head-and-neck cancer patients undergoing chemoradiation were assessed for mucositis at the 5th week. The grades of mucositis were correlated with PTVs of low risk (54 Gy) and high risk (60-66 Gy). STATISTICAL ANALYSIS USED: The data were analyzed using the statistical software, SPSS Inc. Release 2009, predictive analytics software statistics for windows version 20.0, Chicago. Log transformation was done as the data were skewed. Independent t-test was used to compare between the two grades of toxicity. P <0.01 was considered for statistical significance. RESULTS: The mean PTVlow risk was 522cc (228-771) and PTVhigh risk was 254cc (20-780). Grade II mucositis was seen in 27 (67%) patients and Grade III in 11 (28%) patients. The mean PTVlow risk was higher for patients, who had Grade III compared to Grade II mucositis (571 vs. 517 cc, P = 0.052). CONCLUSIONS: The same was seen for PTVhigh risk(367 vs. 222 cc, P = 0.017). PTV is a better predictor of mucositis, and those patients with larger PTV require close monitoring and early intervention of mucositis.

Predicting toxicity for head and neck cancer patients undergoing radiation therapy: an independent and external validation of MDASI-HN based nomogram.

AIM: We conducted a study to validate the MDASI-HN based nomogram, which is used to predict the acute toxicities in head and neck cancer patients undergoing radiation therapy with or without chemotherapy. BACKGROUND: Tolerance to radiation varies from patient to patient and also depends on various other factors like tumor volume, dose of radiation, chemotherapy. Predicting the toxicities allow us to identify potential candidates who are likely to have a higher toxicity and, in addition, evaluates the nomogram when done on an independent group of patients. MATERIALS AND METHODS: Sixty biopsy confirmed head and neck cancer patients undergoing radiation were the subjects of the study. The patients completed patient reported outcome instrument (PRO) MDASI-HN questionnaire at the beginning and at the fifth week of radiation. The baseline score obtained was used to obtain the predicted score using nomogram. The nomogram was also externally validated as per the TRIPOD guidelines. RESULTS: The mean baseline, predicted and score at the fifth week were 27.28 ± 11.04, 73.33 ± 15.51 and 82.62 ± 17.67, respectively, for all sub-sites. A positive, significant correlation (p < 0.01) between the predicted score and the score at the fifth week was seen across all sub sites such as Oral cavity (p = 0.05), Oropharynx (p = 0.02), Hypo pharynx (p = 0.02) and Larynx (p = 0.02). CONCLUSION: The MDASI-HN questionnaire based nomogram is simple, easily doable and takes into consideration the initial symptoms as well the treatment details; thereby, it is able to predict the toxicities accurately.