Uma Goyal

A pilot study of ultrasound-guided electronic brachytherapy for skin cancer.

Purpose Electronic brachytherapy (eBT) has gained acceptance over the past 5 years for the treatment of non-melanomatous skin cancer (NMSC). Although the prescription depth and radial margins can be chosen using clinical judgment based on visual and biopsy-derived information, we sought a more objective modality of measurement for eBT planning by using ultrasound (US) to measure superficial (< 5 mm depth) lesions. Material and methods From December 2013 to April 2015, 19 patients with 23 pathologically proven NMSCs underwent a clinical examination and US evaluation of the lesions prior to initiating a course of eBT. Twenty lesions were basal cell carcinoma and 3 lesions were squamous cell carcinoma. The most common location was the nose (10 lesions). A 14 or 18 MHz US unit was used by an experienced radiologist to determine depth and lateral extension of lesions. The US-measured depth was then used to define prescription depth for eBT planning without an added margin. A margin of 7 mm was added radially to the US lateral extent measurements, and an appropriate cone applicator size was chosen to cover the target volume. Results The mean depth of the lesions was 2.1 mm with a range of 1-3.4 mm, and the mean largest diameter of the lesions was 8 mm with a range of 2.6-20 mm. Dose ranged from 32-50 Gy in 8-20 fractions with a median dose of 40 Gy in 10 fractions. All patients had a complete response and no failures have occurred with a median follow-up of 12 months (range of 6-22 months). Also, no prolonged skin toxicities have occurred. Conclusions A routinely available radiological US unit can objectively determine depth and lateral extension of NMSC lesions for more accurate eBT treatment planning, and should be considered in future eBT treatment guidelines.

Image guided volumetric response during chemoradiotherapy for head and neck squamous cell carcinoma as a predictor of disease outcomes

PURPOSE The goal of this study was to correlate volumetric image guided disease response to clinical outcomes in patients receiving chemoradiation therapy (CRT) for locally advanced head and neck squamous cell carcinoma (HNSCC). MATERIALS AND METHODS Thirty four patients completing definitive CRT for locally advanced HNSCC with megavoltage computed tomography (MVCT) guided tomotherapy IMRT were retrospectively reviewed for volumetric response. Grossly identifiable primary tumor (PT) and nodal disease (ND) response was evaluated by weekly MVCT regression. Percent end-of-treatment (EOT) residual volumes and regression rates were correlated with risk of local failure (LF), progression free survival (PFS), and overall survival (OS). RESULTS A total of 7 LFs were identified in 6 patients at a median follow-up of 8months. The mean percent EOT residual volumes for PT and ND in patients with and without LF were 20% vs. 5% (p=0.005) and 47% vs. 6% (p=0.0001), respectively. The PT and ND volume regression rates for patients with and without LF were 12.7% per week vs. 15.9% per week (p=0.04) and 3.4% per week vs. 10.5% per week (p<0.001), respectively. Utilizing an EOT cut-off value of 25% residual volume, the relative risks of LF for PT and ND were 14.7 (p=0.03) and 25 (p=0.001), respectively. Patients found with PT and/or ND residual volumes <25% at EOT had longer 2year OS of 100% vs. 67% (p=0.0023) and PFS of 87% vs. 17% (p<0.001) compared with patients with residual volumes >/= 25% at EOT. CONCLUSION Patients with locally advanced HNSCC who have significant MVCT volume reduction over the course of definitive CRT tend to have favorable clinical outcomes.

Radiotherapeutic management of vestibular schwannomas using size- and location-adapted fractionation regimens to maximize the therapeutic ratio

BACKGROUND We evaluated and compared the radiographic and clinical outcomes of patients with vestibular schwannomas treated with single fraction stereotactic radiosurgery (SRS), 5 fractions of hypofractionated stereotactic radiation therapy (hSRT), or 25 to 30 fractions of conventionally fractionated stereotactic radiation therapy (cfSRT). METHODS AND MATERIALS Fifty-six patients treated with LINAC-based SRS (median, 12.5 Gy), hSRT (25 Gy), or cfSRT (median, 54 Gy) were retrospectively reviewed. Fractionation was based on the size of the tumor, proximity to the brainstem, and potential risk of neurological sequelae. Median follow-up time was 55.2 months. RESULTS The pretreatment median tumor diameter was significantly smaller for SRS (1.14 cm) compared with hSRT (1.7 cm) (P = .03) and cfSRT (2.0 cm) (P < .001). The overall local tumor control was 96.4%: 100% SRS, 100% hSRT, and 90% cfSRT (P = .19). Tumor regression was observed in 53.3% of SRS, 76.2% of hSRT, and 90% of cfSRT (P = .05). There was less transient expansion of tumors treated with cfSRT (5%) than with SRS (53.3%) or hSRT (28.6%) (P = .005). The median time to regression was 13.8 months for SRS, 14.2 months for hSRT, and 5.5 months for cfSRT (P = .34). There was a 3.6% incidence of grade 3 trigeminal neuropathy, but there was no grade 3 facial neuropathy. CONCLUSIONS All 3 regimens demonstrated similar excellent local control with minimal toxicity; however, the ability of hSRT to treat larger tumors with comparable outcomes to SRS and greater patient convenience when compared with cfSRT suggest that hSRT may offer the optimal treatment approach.

The feasibility of using ultrasound during follow-up for superficial non-melanoma skin cancers after electronic brachytherapy

Purpose Non-melanoma skin cancers (NMSCs) can be treated with a number of modalities including surgery, topical chemotherapy, or radiotherapy. Amongst the radiotherapeutic options, electronic brachytherapy (eBT) is an appealing treatment as it is usually given in a few fractions, it leads to good outcomes, and is increasingly being used. However, currently no follow-up imaging is routinely used or recommended to evaluate treatment response of NMSC. We aimed to use ultrasound (US) in follow-up after eBT for superficial NMSC to assess its feasibility in detecting possible tumor response. Material and methods Fourteen patients were treated between 2013-2015 for a NMSC using eBT. US guidance was used for treatment planning prior to eBT initiation. After completion of eBT, patients were seen in follow-up for both clinical exam and a repeat US at 1 month to evaluate if tumor response was detectable. Results Of the 14 patients, 6 were male and 8 were female. The mean age was 71 years. With a median follow-up of 20.5 months, all patients had a complete response based on physical exam. Eleven patients appeared to have a complete response based on US obtained > 1 month after completing eBT. To date, there have been no local recurrences or progression, and all patients are alive. Conclusions US is an objective imaging modality that may be able to assess NMSC response after eBT. Based on follow-up imaging, further treatment or observation may be recommended. Although this study is hypothesis generating, larger studies with pathologic confirmation of recurrences would be needed to validate US use for follow-up, avoiding possible painful and scarring biopsies in case of low suspicion of recurrence.

Does ultrasound measurement improve the accuracy of electronic brachytherapy in the treatment of superficial non-melanomatous skin cancer?

Purpose Electronic brachytherapy (eBT) is a form of contact radiation therapy used for thin superficial non-melanomatous skin cancers (NMSCs). An accurate measurement of diameter and depth is important for eBT treatment planning. Therefore, we compared clinical measurements by an experienced physician to measurements obtained using ultrasound (US), an objective imaging modality, in order to determine if clinical measurements were accurate enough for adequate NMSC treatment. Material and methods Eighteen patients with 20 biopsy-proven NMSCs first had a clinical examination and then an US evaluation prior to starting eBT. One physician provided a clinical measurement for diameter and depth based on physical examination during radiation oncology consultation. The patients then had an US evaluation with a 14 or 18 MHz US unit, to determine both the diameter and depth measurements; eBT dose prescription was done using the US derived measurements. The clinical measurements and US measurements were compared using a t-test. Results Seventeen lesions were basal cell carcinoma and 3 lesions were squamous cell carcinoma. The most common location was the nose (10 lesions). The difference between the clinical and the US derived measurements for the second largest diameter was found to be statistically significant (p = 0.03), while the difference for the largest diameter of the lesions was not (p = 0.24). More importantly, the depth measurements obtained with US were also found to be significantly different from the clinical estimates (p = 0.02). All patients have had a complete response to therapy with a median follow-up of 24 months. Conclusions Statistically different measurements were obtained in 2 of 3 parameters used in choosing applicator size and prescription depth using an US assessment. The data presented suggests that US is a more objective modality than clinical judgment for determining superficial NMSC diameter and prescription depth for personalized eBT planning.

Role of Concurrent Systemic Therapy with Adjuvant Radiation Therapy for Locally Advanced Cutaneous Head and Neck Squamous Cell Carcinoma

Objective To evaluate the role of concurrent systemic therapy to postoperative radiation therapy (RT) for locally advanced cutaneous head and neck squamous cell carcinoma (LA-cHNSCC). Materials and methods A retrospective study of 32 patients with LA-cHNSCC receiving postoperative RT with and without systemic therapy was conducted. Patients with LA-cHNSCC after surgical resection with one or more high risk features were evaluated. Local regional control (LRC), distant control (DC), and acute and late toxicities were evaluated with Fisher exact tests. Progression-free survival (PFS) and overall survival (OS) were evaluated utilizing Kaplan Meier and log-rank analyses. Univariate Cox proportional hazard analyses were used to examine patient, disease, and treatment-related factors with OS and PFS. Results While comparing patients receiving RT with systemic therapy (n = 14) vs RT alone (n = 18), LRC was 92.9% vs 72.2% (p = 0.20), DC 92.9% vs 94.4% (p = 1.0), median PFS 17.7 months vs 34.4 months (p = 0.48), and median OS 20.9 months vs 34.4 months (p = 0.03), respectively. On univariate analyses, use of concurrent systemic therapy was associated with an increased risk of death with an HR of 3.5 [95% confidence interval (CI): 1.04 - 11.6] (p = 0.04), while patients treated for recurrent disease who had previously treated superficial primaries had improved OS with an HR of 0.10 [95% CI: 0.01-0.80] (p = 0.03). There were no significant differences in acute or chronic toxicities between groups. Conclusions Patients receiving postoperative RT alone for LA-cHNSCC had better OS than patients receiving concurrent systemic therapy. There were no differences in any other endpoints evaluated.

Simple shielding reduces dose to the contralateral breast during prone breast cancer radiotherapy

Our goal was to design a prone breast shield for the contralateral breast and study its efficacy in decreasing scatter radiation to the contralateral breast in a prone breast phantom setup receiving radiation therapy designed for breast cancer. We constructed a prone breast phantom setup consisting of (1) A thermoplastic mask with a left-sided depression created by a water balloon for a breast shape; (2) 2 plastic bags to hold water in the thermoplastic mask depression; (3) 2000mL of water to fill the thermoplastic mask depression to create a water-based false breast; (4) 1-cm thick bolus placed in the contralateral breast holder; (5) 2 lead (Pb) sheets, each 0.1-cm thick for blocking scatter radiation in the contralateral bolus-based false breast; (6) a prone breast board to hold the thermoplastic mask, water, bolus, and lead; (7) 9cm solid water on top of the breast board to simulate body; (8) a diode was used to verify dose for each treatment field of the treated water-based breast; (9) metal-oxide-semiconductor-field effect transistor (MOSFET) dosimeters to measure dose to the contralateral bolus-based breast. The phantom prone breast setup was CT simulated and treatment was designed with 95% isodose line covering the treated breast. The maximum dose was 107.1%. Megavoltage (MV) port images ensured accurate setup. Measurements were done using diodes on the treated water-based breast and MOSFET dosimeters at the medial and lateral sides of the contralateral bolus-based breast without and with the Pb shield. Five treatments were done for each of the 3 data sets and recorded individually for statistical purposes. All treatments were completed with 6MV photons at 200cGy per treatment. The dose contributions from each of the 3 data sets including 15 treatments total without and with the prone lead shield to the medial and lateral portions of contralateral bolus-based breast were averaged individually. Unshielded dose means were 37.11 and 2.94cGy, and shielded dose means were 12.68 and 1.54cGy, respectively. When comparing medial and lateral portions of the contralateral bolus-based doses without and with Pb, the shield significantly reduced dose to both sides of the contralateral breast (medial p = 2.64 × 10(-14), lateral p = 4.91 × 10(-6)). The prone 0.2-cm Pb shield significantly reduced scatter dose to the contralateral breast on the order of 2 to 3 times. Reductions may be clinically relevant for women younger than 45 years by decreasing the risk of contralateral radiation-induced breast cancer in patients receiving radiation therapy for breast cancer. This shield is simple as it would be a part of the prone breast board during treatments, but future studies are warranted for safety and efficacy clinically.