RESUMO
Purpose: For the treatment of invisible lung tumours with CyberKnife (CK), fiducial markers (FMs) were implanted as an internal surrogate under virtual bronchoscopic navigation (VBN). This research aims to study the benefits of introducing an additional procedure in assigning the optimal FM positions using a pre-procedure planning system and performing virtual simulation before implantation. The objectives were 1) to reduce the duration of the FM implantation procedure, 2) to reduce the radiation exposure in dose area product (DAP) (dGy*cm2) to patients, and 3) to increase the number of FMs implanted around the tumour. Methods and Materials: This study is retrospective, single-centre, and observational in nature. A total of 32 patients were divided into two groups. In Group 1, 18 patients underwent conventional VBN FM implantation. In Group 2, 14 patients underwent additional pre-procedure planning and simulation. The steps of pre-procedure planning include 1) importing CT images into the treatment planning system (Eclipse, Varian Medical Systems, Inc.) and delineating five to six FMs in their ideal virtual positions and 2) copying the FM configuration into VBN planning software (LungPoint Bronchus Medical, Inc.) for verification and simulation. Finally, the verified FMs were deployed through VBN with the guidance of the LungPoint planning software. Results: A total of 162 FMs were implanted among 35 lesions in 32 patients aged from 37 to 92 (median = 66; 16 men and 16 women). Results showed that 1) the average FM insertion time was shortened from 41 min (SD = 2.05) to 23 min (SD = 1.25), p = 0.00; 2) the average absorbed dose of patients in DAP was decreased from 67.4 cGy*cm2 (SD = 14.48) to 25.3 cGy*cm2 (SD = 3.82), p = 0.01 (1-tailed); and 3) the average number of FMs implanted around the tumour was increased from 4.7 (SD = 0.84) to 5.6 (SD = 0.76), p = 0.00 (1-tailed). Conclusion: Pre-procedure planning reduces the FM implantation duration from 41.1 to 22.9 min, reduces the radiation exposure in DAP from 67.4 to 25.3 dGy*cm2, and increases the number of FMs inserted around the tumour from 4.7 to 5.6.
RESUMO
BACKGROUND: The Intergroup 0116 study demonstrated that concurrent chemoradiation improved overall survival (OS) in resected gastric cancer. However, there are few reports focusing on late toxicity and factors governing prognosis. This study aimed to determine these two important aspects for employing this regimen. METHODS: Patients with resected gastric cancer stage IB to IV (M0) disease, treated between July 1998 and December 2007, were analyzed. The majority of the patients were treated using 5 cycles of 5-fluorouracil (5FU)/leucovorin chemotherapy with 45 Gy/25 fractions radiotherapy concurrent with cycles 2 and 3, as per the Intergroup 0116 study. RESULTS: We treated 120 patients (107 standard protocol, 13 with concurrent 5FU alone), and 14% had a close or positive margin. Median age was 59 years (35-79 years). Acute toxicity ≥ grade 3 was seen in 66% of all patients (hematological 61%, stomatitis 3%, diarrhea 6%, vomiting 2%). Median follow-up was 33 months (range 6-125 months). Five-year OS and relapse-free survival were 51 and 54%, respectively. On multivariate analysis, surgical margin status, stage of the disease, and radiotherapy with computed tomography (CT) planning were important prognostic factors. Anemia and gastritis were the two most frequently occurring late complications, though they were usually mild and asymptomatic. Clinically significant renal impairment was uncommon. Other rare complications included intestinal obstruction, malabsorption, hypertension, and secondary malignancy. CONCLUSIONS: Postoperative chemoradiation is safe and late toxicity is usually mild in extent. Results were comparable to the Intergroup 0116 study. R0 resection is of utmost importance and radiotherapy should best be delivered by conformal techniques.