A randomized study for dosimetric assessment and clinical impact of bone marrow sparing intensity-modulated radiation therapy versus 3-dimensional conformal radiation therapy on hematological and gastrointestinal toxicities in cervical cancer.

Background: Cervical cancer requires multimodality therapy, resulting in acute toxicities. Intensity-modulated radiation therapy (IMRT) is postulated to spare bone marrow (BM) and bowel to reduce acute hematological and gastrointestinal (GI) toxicities of chemoradiotherapy. Patients and Methods: This is a prospective randomized phase III study enrolling patients with Stage IB to IVA cervical carcinoma in two arms receiving either three-dimensional conformal radiotherapy (3DCRT) or IMRT from December 2017 to December 2019. The primary objective was to compare the hematologic toxicities (Grade 2 or more neutropenia as the primary factor) and the secondary objectives were to compare GI toxicities, and dosimetric analysis for volumes of BM, and bowel irradiated. SPSS version 20 was used for all statistical calculations. Results: Eighty patients with histopathologically confirmed cervical cancer were randomized to receive IMRT or 3DCRT (40 in each arm). The median age of the patients was 56.5 (36-67) and 59.5 (37-68) years, respectively, in IMRT and 3DCRT arms. The median dose of external radiation was 50 Gy in 25 fractions, and of brachytherapy was 24 Gy in 3 fractions in both the arms. The incidence of grade ≥2 neutropenia was 42.5% and 15% in the 3DCRT and IMRT arms, respectively (P < 0.001). All patients received concurrent chemotherapy with cisplatin, with the median number of cycles being 5 (range 3-5) in both the arms. All five cycles of concurrent chemotherapy could be completed in 25 (62.5%) patients in the IMRT arm and 24 (60%) patients in the 3DCRT arm. Conclusions: IMRT significantly reduces acute hematologic and GI toxicities compared with 3DCRT with a better dosimetry profile.

Quantitative estimation of doses to salivary glands from using brachytherapy in head and neck cancers.

PURPOSE: To quantify the percentage doses received by salivary glands (SGDs) in head and neck interstitial brachytherapy (BT). METHODS AND MATERIALS: The study included 43 patients who underwent high-dose rate iridium-192 implant for oral cavity and oropharyngeal lesions treated with BT as a boost. BT dose varied with disease stage and external radiation dose, with the total mean dose of 66±4Gy. Patients were divided into two groups, midline and lateralized, based on anatomic implant location. Different dose parameters such as D(max), D(mean), DV(30%) of individual glands were derived from dose volume histogram representing the percentage maximum dose, mean dose, and dose received by 30% volume of individual SGDs, respectively. For better perception of the impact of BT on individual SGDs, the doses received are extrapolated to radical BT dose of 60Gy. RESULTS: For lateralized implants, the highest dose received by ipsilateral parotid (PTD) was 12.3% seen in tonsillar implants. The contralateral PTD receives minimal doses. As expected, the ipsilateral submandibular gland (SMG) received high doses in the range of 80% of the total prescribed dose, whereas contralateral SMG received 10% of ipsilateral dose. For the midline implants, the mean dose range for PTD was 7-11% of the total prescribed dose and for SMG between 17% and 56%, depending on the location. CONCLUSIONS: The study quantifies the percentage doses received by the individual SGDs in interstitial head and neck BT for use in future planning of the BT procedures and for salivary functional studies, prediction of damage, and quality-of-life parameters.

Brachytherapy boost: a novel approach for epiglottic carcinoma.

PURPOSE: Epiglottic (epilaryngeal) carcinoma has been treated conventionally by radical external beam radiotherapy or partial laryngectomy. The aim of this study is to evaluate the role of brachytherapy boost as a novel approach for lingual epiglottic lesions. METHODS AND MATERIALS: Twenty-three patients with T(2-3)N(0-1) lingual epiglottic carcinoma (SCC) were treated with curative intent between January 1990 and December 2001 using low dose rate interstitial (192)Ir implant boost, moderate dose of 25Gy at 0.5cm (mean dose rate, 50.5 cGy/h) 3 weeks after moderate dose of external beam radiotherapy (mEBRT) of 46Gy/23#/28-31d. RESULTS: Complete response after mEBRT was observed in 18 of the 23 patients (78%) and partial response was seen in 5 of the 23 patients (22%). After implant, all patients had complete response. Locoregional control was seen in 19 of the 23 patients (82.6%). Two patients developed distant metastases. Disease-free survival and overall survival at 5 years were 68.3% and 66.7%, respectively. Disease-free survival at 5 years showed a trend toward better outcome for biologically equivalent doses >85Gy compared with biologically equivalent doses <85Gy (80% vs. 68%) (p=0.18). All patients had minimal to acceptable xerostomia. CONCLUSIONS: Interstitial boost with mEBRT is feasible, effective, and a novel approach for lingual epiglottic lesions.