Luluel Khan

Optimization of imaging diagnosis of 1-2 cm hepatocellular carcinoma: an analysis of diagnostic performance and resource utilization.

BACKGROUND & AIMS To determine the optimal imaging scan or combinations in terms of diagnostic performance and resource utilization for 1-2 cm nodules found on surveillance for hepatocellular carcinoma. METHODS Eighty-four cirrhotic patients with 101, 1-2 cm nodules (34 malignant, 67 non-malignant) prospectively underwent standardized contrast-enhanced ultrasound, CT, and MRI scans. Sensitivity/specificity and potential imaging/biopsy utilization of individual imaging modalities and two-modality combinations performed at the same time (coincidental) or in sequence were measured. Final diagnosis was determined by biopsy (23), growth (10), recurrence (1), or stability in size for ≥ 18 months (67). RESULTS For single imaging scans, sensitivities/specificities ranged between 53-62% and 91-100%. When two scans were combined requiring both to be positive, sensitivities/specificities ranged between 29-41% and 99-100%. When two scans were combined sequentially, requiring only one to be positive, sensitivities/specificities ranged between 74-89% and 91-99%. When comparing combination of two positive tests (MRI and CT) to MRI alone, there was a significant drop in sensitivity (41% vs. 62%, p=0.02), no change in specificity (both 100%), with twice as many scans performed, and 9% rise in potential biopsies or 7% rise in follow-up scans. When comparing the combination of MRI then CT (if MRI negative) to MRI alone, there was an insignificant rise in sensitivity (74% vs. 62%, p=0.13), drop in specificity (97% vs. 100%), with 77% more scans performed, and 6% drop in potential biopsies or 7% drop in potential follow-up scans. CONCLUSIONS Single imaging scans have similar specificity to two coincidental positive scans with much less resource utilization. Sequential imaging provides the best sensitivity but with diminished specificity.

Predictors of recurrence after radiotherapy for non-melanoma skin cancer

Predictive factors of recurrence were examined in 448 non-melanoma skin cancers (72% basal cell carcinoma, 28% squamous cell carcinoma) treated with radiotherapy. The overall recurrence rate was 15.8% at a median follow-up of 18.4 months. In multivariate analysis, significant factors for recurrence were age (p = 0.0197), tumour size 2 cm or greater (p = 0.0095), immunosuppression (p = 0.0082), and treatment modality (p = 0.0009).

Recommendations for CTV margins in radiotherapy planning for non melanoma skin cancer

PURPOSE To provide practice guidelines for delineating clinical target volume (CTV) for radiotherapy planning of non melanoma (NMSC) skin cancers. METHODS AND MATERIALS A prospective, single arm, study. Preoperatively, a radiation oncologist outlined the boundary of a gross lesion, and drew 5-mm incremental marks in four directions from the delineated border. Under local anesthesia, the lesion was excised, and resection margins were assessed microscopically by frozen section. Once resection margins were clear, the microscopic tumor extent was calculated using the presurgical incremental markings as references. A potential relationship between the distance of microscopic tumor extension and other variables was analyzed. RESULTS A total of 159 lesions in 150 consecutive patients, selected for surgical excision with frozen section assisted assessment of resection margins, were accrued. The distance of microscopic tumor extension beyond a gross lesion varied from 1mm to 15 mm, with a mean of 5.3mm. The microscopic tumor extent was positively correlated with the size of gross lesion, histology and number of surgical attempts required to obtain a clear margin. To provide a 95% or greater chance of covering microscopic disease we make the following recommendations for CTV margins; 10mm for BCC less than 2 cm, 13 mm for BCC greater than 2 cm, 11 mm for SCC less than 2 cm, and 14 mm for SCC greater than 2 cm. CONCLUSIONS Tumors greater than 2 cm and SCC histology required larger margins to adequately cover the microscopic extent of disease. This information is crucial in radiation planning of NMSC. Clinicians should be cautioned, as these guidelines may not offer optimum treatment for patients with extremely large or small lesions.

Investigation of Dose Falloff for Intact Brain Metastases and Surgical Cavities Using Hypofractionated Volumetric Modulated Arc Radiotherapy.

Introduction: Intact brain metastases tend to be small and spherical compared to postsurgery brain cavities, which tend to be large and irregular shaped and, as a result, a challenge with respect to treatment planning. The purpose of the present study is to develop guidelines for normal brain tissue dose and to investigate whether there is a dependence on target type for patients treated with hypofractionated volumetric modulated arc radiotherapy (HF-VMAT). Methods: Treatment plans from a total of 100 patients and 136 targets (55 cavity and 81 intact) were retrospectively reviewed. All targets were treated with HF-VMAT with total doses ranging between 20 and 30 gray (Gy) in 5 fractions. All plans met institutional objectives for organ-at-risk constraints and were clinically delivered. Dose falloff was quantified using gradient index (GI) and distance between the 100% and 50% isodose lines (R50). Additionally, the dose to normal brain tissue (brain contour excluding all gross tumor or clinical target volumes) was assessed using volume receiving specific doses (Vx) where x ranged from 5 to 30 Gy. Best-fit curves using power law relationships of the form y = axb were generated for GI, R50, and Vx (normal brain tissue) versus target volume. Results: There was a statistically significant difference in planning target volume (PTV) for cavities versus intact metastases with mean volumes of 37.8 cm3 and 9.5 cm3, respectively (P < .0001). The GI and R50 were statistically different: 3.4 and 9.8 mm for cavities versus 4.6 and 8.3 mm for intact metastases (P < .0001). The R50 increased with PTV with power law coefficients (a, b) = (6.3, 0.12) and (5.9, 0.15) for cavities and intact, respectively. GI decreased with PTV with coefficients (a, b) = (5.9, −0.18) and (5.7, −0.14) for cavities and intact, respectively. The normal brain tissue Vx also exhibited power law relationships with PTV for x = 20 to 28.8 Gy. In conclusion, target volume is the main predictor of dose falloff. The results of the present study can be used for determining target volume-based thresholds for dose falloff and normal brain tissue dose–volume constraints.

A single institution experience of extranodal natural killer/T cell lymphoma of nasal type

Abstract Extranodal natural killer/T cell lymphoma (ENKTL) nasal type is a rare form of non-Hodgkin lymphoma that is more commonly seen in Asia and Latin America than in North America or Europe. The purpose of this study was to determine the treatment outcomes with a combined modality approach and whether treatment outcomes varied according to ethnicity in patients with ENKTL, nasal type in Toronto, Canada. Patients presenting with ENKTL, nasal type, between 1994 and 2011 were retrospectively reviewed. Patient characteristics, including the patients ethnic origin, treatment details and outcomes were recorded and analyzed for significant differences between Asian and Caucasian patients. A total of 34 patients were identified: 16 Asian, 16 Caucasian, one Aboriginal and one Hispanic. All patients had nasal cavity involvement. The majority had localized disease: stage I (n = 22), stage II (n = 6); and stage IV in six patients. Combined radiotherapy (RT) and chemotherapy was intended for 32 of the 34 patients, with two receiving RT alone. Median RT dose was 45 Gy (range: 35–50.4 Gy). Response to initial treatment was observed in 44% of patients. Two-year disease-free survival was 17.8% (Asian patients: 18.8%, Caucasians: 20%, p = 0.82), and overall survival 39.2% (Asian patients: 30%, Caucasians: 42%, p = 0.52). There were no significant differences in clinical outcomes in terms of patient ethnicity. A combined modality approach (with cyclophosphamide, doxorubicin, vincristine, prednisone [CHOP] chemotherapy administered initially) is of limited effectiveness. We have now adopted the use of RT as the initial treatment approach, followed by multiagent chemotherapy.