Neoadjuvant QUAD shot for downstaging or temporizing locally advanced oral cavity cancer prior to definitive surgery.

OBJECTIVES: The mainstay of oral cavity cancer treatment is surgery, often with adjuvant therapies. However, patients often present with locally advanced disease and downstaging would render surgery more feasible. We evaluated hypofractionated radiation therapy (QUAD Shot) prior to definitive surgery for head and neck cancers, with a goal of downstaging. MATERIALS AND METHODS: Eighteen patients with primary head and neck malignancy, predominantly locally advanced oral cavity cancers, received QUAD Shot radiation therapy from June 2016 to July 2021. External beam radiation therapy was delivered to the primary lesion in four fractions over two days, two fractions/day at least six hours apart with total dose ranging from 1400 cGy to 1500 cGy. Twelve patients proceeded to definitive surgery. RESULTS: Of the twelve patients receiving surgery, one had complete response to radiation therapy with no pathological disease seen at surgery. Four patients had a partial response, defined as downstaging on final pathology. Five patients showed no response, and two had progressive disease defined as upstaging on final pathology. Seven patients had radiographic primary tumor shrinkage ≥ 0.5 cm following Quad Shot. The Quad Shot was tolerated well with no reported adverse effects. CONCLUSION: Discrepancies between clinical- and pathological-staging are common and expected. However, ∼40 % of our patients experienced downstaging following QUAD Shot. Thus, neoadjuvant radiation therapy may be viable for temporizing tumor growth while awaiting surgery, or for downstaging and thus facilitating more technically feasible and less morbid surgery for locally advanced head and neck cancers.

Ocular malignancies treated with iodine-125 low dose rate (LDR) brachytherapy at a single high-volume institution: A retrospective review.

The aim of our study is to document our cases of choroidal melanoma treated with low dose rate (LDR) brachytherapy and to correlate the dosimetry and radiobiology with clinical effects and oncologic outcomes. Data from 157 patients treated from 2014 to 2018 with LDR brachytherapy were used for this investigation. Treatments used a collaborative ocular melanoma study eye plaque and Iodine-125 radioactive seeds. The seeds activities were chosen to deliver 85 Gy to the tumor apex or to a prescription point (if the apex < 5 mm). The plaque sizes used were 10, 12, 14, 16, 18, 20, and 22 mm including notched or deep notched. The plaques were modeled in Varian BrachyVision version 11.6 (Varian Medical Systems) with seed coordinates from the AAPM Task Group 129. The Task Group 43 from AAPM was used for brachytherapy dose planning. Dose data were extracted for the apex, prescription point, sclera, retina opposite to the implant, lens, macula, and optic disc. The radiobiological dosimetry were calculated using appropriate α/ß ratios found in the literature and then correlated to clinical side effects. Average biologically effective dose for associated organs at risk were calculated in cases where toxicity occurred. These included: radiation cataract (70.66 Gy), disc atrophy (475.49 Gy), foveal atrophy (263.07 Gy), radiation papillopathy (373.45 Gy), radiation maculopathy (213.62 Gy), vitreous hemorrhage (1437.68 Gy), vascular occlusion (1080.93 Gy), nonproliferative retinopathy (1066.89 Gy), proliferative retinopathy (1590.71 Gy), exudative retinal detachment (1364.32 Gy), and rhegmatogenous retinal detachment (2265.54 Gy). Average biologically effective dose was higher in patients who developed radiation induced long term side effects than in the whole patient population except for radiation maculopathy. In spite of the small patient population and short-term follow-up, it is of interest to correlate the radiation induced effects and create a guideline for the improvement of the treatment of patients treated with LDR brachytherapy.

Merkel cell carcinoma: treatment and outcomes over a 10-year period at a high-volume academic center.

BACKGROUND: Merkel cell carcinoma (MCC) is a rare, highly aggressive malignancy which lacks high-level evidence-based treatment guidelines. METHODS: To determine outcomes of MCC patients and assess the role of radiation in treatment, we performed a retrospective chart review of patients treated for MCC between 2006 and 2016 at a single high-volume academic medical center. The primary outcome was overall survival (OS) for the entire population and for those populations receiving specific therapies. RESULTS: Forty-two patients were evaluable. OS for all patients was not reached since most remain alive at time of analysis. OS for the American Joint Committee on Cancer (AJCC) stage I was not reached. OS for stages II, III, and IV was 37.3 months (6.8, -), 49.5 months (14.2, 49.5), and 14.5 months (10.8, -), respectively. OS could not be reached in the high radiotherapy (RT) dose group (biologically equivalent dose [BED] ≥ 60) and was 49.5 months (10.8, -) in the low-dose group (BED < 60). For surgical margin status, OS was 14.9158 months (6.8008, -) for positive margins and 37.3 months (10.8, -) for negative margins. CONCLUSIONS: No conclusive findings for OS were identified; however, trends for improved OS were associated with lower AJCC staging, negative surgical margins, and high RT doses.

Intensity-modulated proton therapy (IMPT) versus intensity-modulated radiation therapy (IMRT) for the treatment of head and neck cancer: A dosimetric comparison.

It is the goal of this study to compare the dosimetric advantages of IMPT when compared to IMRT. From January 2019 to August 2020, 25 patients were treated with intensity modulated proton therapy (IMPT) at our institution for either recurrent, metastatic, benign, or primary tumors in the head and neck region. Twenty-one patients met criteria for dosimetric analysis. Histology of disease included squamous cell carcinoma, acinic cell carcinoma, sarcomatoid sinonasal carcinoma, paraganglioma, adenoid cystic carcinoma, salivary high grade carcinoma, and papillary thyroid carcinoma. For IMRT planning, gross tumor volume (GTV) and clinical target volume (CTV) were contoured with the expansion of 3-5 mm to create the planning target volume (PTV) and dose was prescribed to the PTV. For the IMPT planning, dose was prescribed to CTV and robust optimization was utilized which accounted for a 5 mm setup and range uncertainty. The minimum, mean and maximum target doses for IMRT and IMPT plans as well as mean and maximum normal tissue doses are reported for the 21 patients meeting criteria. Mean doses for IMRT and IMPT were 6278.2 cGy and 6449.8 cGyRBE respectively with p-value of 0.0001. Maximum doses for IMRT and IMPT were 6579.5 cGy and 6772.1 cGyRBE respectively with p-value of 0.0014. Minimum doses for IMRT and IMPT were 5440.6 cGy and 5617.9 cGyRBE respectively with p-value of 0.3576. IMPT had an overall advantage in OAR doses in the brain stem, spinal cord, optic structures, cochlea, larynx, contralateral parotid, and oral cavity with only a few exceptions. Our study thus demonstrates a dosimetric advantage for IMPT in treating head and neck tumors in mean and max dose delivered as well as dose to OARs. Given that our patient cohort were mainly unilateral head and neck cases, our study supports the treatment of this specific subset of patients regardless of histology with IMPT. This may aid in appropriate patient selection for IMPT treatment. Further studies will need to determine if this dosimetric advantage translates to a therapeutic advantage for patients.

A prospective single-institution study of intraoperative radiotherapy (IORT) for early-stage breast cancer.

Intraoperative radiation therapy (IORT) is an option for breast-conserving therapy in early-stage breast cancer. IORT is given in one fraction at the time of surgery and eliminates the need for adjuvant external beam radiation therapy. However, previous trials indicate increased local failure rates compared with whole-breast irradiation, which engenders controversy around the appropriate use of IORT. We conducted a prospective study of patients diagnosed with early-stage breast cancer (T1-T2, N0-N1) at the University of Oklahoma Health Sciences Center (OUHSC) between 2013 and 2017 and treated with lumpectomy followed by intraoperative radiation therapy (IORT). Data collected included stage of disease, tumor location, histology, tumor markers, lymph node status, surgical margin size, recurrence, cosmetic outcomes, and length of follow-up. In-breast tumor recurrence rate (IBTR) in the 77 evaluable patients was 3.9% (3 patients). Margins were close (1 mm or less) in all three recurrent patients, and two were initially diagnosed with DCIS. Recurrence rates in our patients were comparable to prior reports. All recurrences were in patients with close margins indicating that this may represent a predictive feature for exclusion from IORT; additional studies are essential to determine the recurrence rates among patients treated with IORT and to identify potential predictors of IORT eligibility.