Dosimetric comparison between carotid-sparing IMRT and 3DCRT in early glottic cancer patients treated with definitive radiation therapy.

BACKGROUND: The purpose of this study was to evaluate the dosimetric benefits of carotid-sparing IMRT (intensity-modulated radiation therapy) over 3DCRT (three-dimensional conformal radiation therapy) in early glottic cancer patients. MATERIAL AND METHODS: Ten patients with histologically proven early-stage squamous cell cancer of glottis (T1N0), treated with definitive radiotherapy, were selected retrospectively for the dosimetric analysis. Patients were originally treated with 3DCRT technique. For comparison purpose, IMRT plans were generated for each patient. Dosimetric comparison was done between two techniques (IMRT and 3DCRT) in terms of PTV (planning target volume) coverage, HI (homogeneity index), CI (conformity index), and doses to right carotid artery, left carotid artery, and spinal cord. RESULTS: V95% for the PTV was higher in IMRT plans (98.26%) as compared to 3DCRT plans (95.12%) (P-value <0.001), whereas V105% for PTV was significantly higher in 3DCRT plans (16.77%) as compared to IMRT plans (0.32%) (P-value 0.11). In terms of both HI and CI, IMRT plans showed better conformity as compared to 3DCRT plans, with statistically significant difference. Both right and left carotid arteries' average mean and maximum doses were significantly lower in IMRT plans as compared to 3DCRT plans (P-value <0.001). IMRT plans resulted in significant carotid-sparing as compared to 3DCRT plans in terms of V35 and V50 (P-value <0.001). CONCLUSION: Carotid-sparing IMRT resulted in better PTV coverage and lower carotid artery dose as compared to 3DCRT in early glottic cancer patients.

Comparative Analysis of VMAT and IMRT Techniques: Evaluation of Dose Constraints and Bone Marrow Sparing in Cervical Cancer Patients Undergoing Chemoradiotherapy.

BACKGROUND: Carcinoma of the cervix is a globally significant cause of morbidity and mortality among women. Concurrent chemoradiotherapy, a standard approach for locally advanced cervical cancer, invariably involves pelvic irradiation. Although this strategy is effective, it inevitably affects the pelvic bone marrow, a crucial hematopoietic site, and leads to hematological toxicity The potential of IMRT to spare bone marrow in pelvic irradiation settings has been an area of significant interest, with the aim to mitigate the hematological toxicity associated with pelvic radiotherapy. Radiotherapy techniques have evolved in terms of conformity and normal tissue sparing. Our study intends to explore the use of BM sparing techniques among patients of carcinoma cervix. PATIENTS AND METHODS: Twenty patients of carcinoma cervix FIGO Stage IIIB treated with concurrent chemoradiotherapy were selected for this study. The external contour of bones was delineated on planning CT as a surrogate for BM. We generated three plans on a single patient:1. without BM as the dose constraint, namely N-IMRT plan; 2. with BM constraint, namely BMS-IMRT plan; 3. VMAT plan in which BM constraint was given. The dose volume histogram (DVH) for planning target volume (PTV) and organs at risk (OAR) were analyzed. BM parameters: V10, V20, V30, V40, mean, maximum and minimum dose were compared.  Results: PTV coverage was comparable in all techniques. VMAT plans resulted in superior BM sparing compared with N-IMRT plan (P-<0.001) and BMS-IMRT plan (P-<0.001, 0.021 and 0.001 respectively for V20, V30 and V40). VMAT plans had better CI compared with BMS-IMRT (P-0.002) and N-IMRT (P-0.001) plans. CONCLUSION: Our study adds to the growing evidence that VMAT might be the preferred technique for patients with carcinoma of the cervix undergoing concurrent chemoradiotherapy, as it provides comparable target coverage and better sparing of bone marrow compared to IMRT.

Intensity-modulated radiotherapy in locally advanced head-and-neck cancers in elderly patients.

Introduction: Head and neck cancer is one of the most common malignancies in Indian males. Due to poor socioeconomic status, presentation is usually in advanced stage. Treatment option is limited to radiotherapy with or without chemotherapy. Intensity-modulated radiotherapy (IMRT) provides highly conformal dose distributions creating nonuniform spatial intensity using different segments in the beam. Concomitant chemoradiation is highly toxic in this age group. Material and Methods: During 2016-2017, 44 patients with locally advanced head-and-neck cancers were treated with a curative intent with IMRT. They were in the age range of 65-75. The median age was 69 years. Thirty five were male and nine were female. Histopathologically, all had squamous cell carcinoma. Stage wise, all were T3N2 or more. The standard technique of IMRT was used with sparing of organs at risk and defining treatment volumes: gross, clinical, and planning. Patients were assessed after 4 weeks of completion of treatment for response and toxicities. Results: Response vise, 14 patients achieved complete response, 28 patients had partial response, and 2 had stable disease. There was no treatment-related mortality. Six patients had treatment interruptions due to toxicity. Incidence of mucositis was of Grade 1-2 in all patients. No hematological toxicity was seen. Patients having dysphagia during treatment were given nasogastric feed.

Conventional Versus Different Hypofractionated Radiotherapy Dosage Schedules in Postmastectomy Advanced Breast Cancer.

Introduction: The standard treatment for advanced breast cancer is surgery consisting of breast-conserving surgery or modified radical mastectomy (MRM) postneoadjuvant chemotherapy followed by adjuvant radiation treatment (RT). Conventionally-fractionated whole breast irradiation has been the standard RT regimen, but recently shorter courses of hypofractionated whole breast or chest wall irradiation have been advocated for patient convenience and reduction in health-care costs and resources. Radiation is delivered through the same technique, but tumors receive a higher dose of radiation per treatment session with hypofractionation. Aim: The aim of the study was to compare different fractionation schedules of radiotherapy in postoperative cancer breast with respect to locoregional control and toxicities. Materials and Methods: One hundred and eighty-eight patients of cancer breast, who received RT between January 2017 and December 2019 were assessed. Since hypofractionation is well documented and established and being practiced in prestigious institutes, we treated the patients as per their choice to receive 10.15 or 25 fractions. 72 patients (Group A) were treated with conventional fractionation to a dose of 50 Gy/25 fractions/5 weeks. Second group of 62 patients (Group B) were given 40.5 Gy/15 fractions/3 weeks and third group of 54 patients (Group C) were treated with 34 Gy/10 fractions/2 weeks. All patients were T3 or more and underwent MRM after neoadjuvant chemotherapy. They were in the age group of 30-65 years. All of them received adjuvant chemotherapy and hormone therapy in case of estrogen/and progesterone receptor positivity and anti-Her2neu target therapy in case of Her2neu positivity. They were assessed for locoregional control and acute and chronic toxicities. Results: Grade 3 and 4 skin toxicity was similar in all three groups. At 6 months postcompletion of RT, two patients in Group A, 3 in Group B, and 5 in Group C lost to follow-up. In rest of the subjects, there was no locoregional failure. At 1 year, 1 patient from Group A, 2 from Group B, and 1 from Group C developed locoregional recurrence. There were no major chronic toxicities. Arm edema and Telangiectasia were similar in three groups. No rib fracture or major cardiotoxicity and pulmonary toxicity was seen. Conclusion: Hypofractionated RT is a part of the typical treatment regimen for breast cancer nowadays. The major advantage is of convenience to the patients as it is completed the full course of RT in fewer sessions. With both conventional and hypofractionated radiation, the patient receives radiation 5 days a week. In the conventional regimen, though the schedule lasts for 5 weeks, whereas hypofractionation therapy is completed in 2 to 3 weeks. Local control wise both conventional and hypofractionated regimen is similar in locoregional control and toxicity. Therefore, hypofractionated RT should be practiced in cancer breast as it is economical, convenient, and toxicity wise and result wise similar to conventional radiotherapy.

Incidence of xerostomia in locally advanced head-and-neck cancers in elderly patients treated with intensity-modulated radiotherapy.

Introduction: Dysphagia and xerostomia are the main sequelae of radiotherapy for head and neck cancer (HNC) and the main factors in reducing the longterm patient quality of life. Intensitymodulated radiotherapy (IMRT) uses advanced technology to focus the high radiation doses on the targets and avoid irradiation of noninvolved tissues. Material and Methods: During 2016-2017, 44 patients of locally advanced HNCs were treated with a curative intent with IMRT. They were in the age range of 65-75 years. The median age was 69 years. Thirtyfive patients were male and nine patients were female. Histopathologically, all had squamous cell carcinoma. Stage wise all were T3N2 or more. No concurrent chemotherapy was given. The Eastern Clinical Oncology Group criteria were used for grading the toxicities. Patients were assessed after 4 weeks of completion of treatment. Results and Conclusion: The incidence of mucositis was of Grade 1-2 in 37 patients. Moreover, patients experienced severe mucositis. Six patients had treatment interruptions due to mucositis. Xerostomia was Grade 1-2 in 42 patients and Grade 3 in 2 patients. Dysphagia was Grade 1-2 only. No hematological toxicity was seen. Patients having dysphagia during the treatment were given nasogastric feed. Response wise 14 patients achieved complete response, 28 patients had partial response, and 2 had stable disease. There was no treatmentrelated mortality.