Medicine
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This repository contains the published and unpublished research of the Faculty of Medicine by the staff members of the faculty
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Item Colonoscopic ultrasound is associated with a learning phenomenon despite previous rigid probe experience(Springer India, 2009) Siriwardana, P.N.; Hewavisenthi, S.J.de S.; Pathmeswaran, A.; Deen, K.I.Colonoscopic ultrasound (CUS) enables total colonoscopic examination combined with staging of tumor. Rigid probe transrectal ultrasound (TRUS) is reliable in assessing rectal cancer. Both the modalities are associated with an initial learning curve. We evaluated the predictability CUS in preoperative staging of rectal cancer during the learning curve, despite experience with TRUS. Forty-four patients with non-obstructing rectal cancer were assessed by colonoscopy and colonic ultrasound using a 7.5 MHz rotating transducer. Accuracy of ultrasound staging was compared with pathological staging. Tumor staging and nodal staging at pathology and ultrasound were named pT, pN and uT, uN, respectively. The pathological staging was pT1 in two (4.5%), pT2 in 16 (36%), pT3 in 21 (48%) and pT4 in five (11.5%) rectal cancer specimens. CUS understaged the tumor in 11 cases and overstaged it in 10 cases. Overall, the positive predictive value was 61%, negative predictive value 73%, sensitivity 61%, and specificity 73%. Lymph nodes were not visualized in 14. The overall un-weighted kappa of CUS staging of RC was 0.18 (poor). The predictive value in tumor staging of CUS is suboptimal in the learning phase, despite previous experience with TRUS.Item Neoadjuvant therapy for rectal cancer down-stages the tumor but reduces lymph node harvest significantly(Springer International, 2005) Wijesuriya, S.R.E.; Deen, K.I.; Hewavisenthi, J.; Balawardana, J.; Perera, M.PURPOSE: The impact of neoadjuvant therapy (NAT) for rectal cancer on lymph node yield is not well known. This study evaluates the impact of NAT on tumor regression and lymph node harvest. METHODS: The subjects were 40 patients with rectal cancer; 20 receiving high-dose, long-course neoadjuvant therapy, and 20 age- and sex-matched controls who did not receive neoadjuvant therapy. Tumor regression (TRG) was graded from 1 to 5 as: TRG1, no residual tumor cells; TRG2, occasional residual tumor cells with marked fibrosis; TRG3, marked fibrosis with scattered tumor cells or groups; TRG4, abundant cancer cells with little fibrosis; TRG5, no tumor regression. We also evaluated the number of lymph nodes retrieved from excised specimens, the size of the largest node, and the extent of lymph node involvement by the tumor. RESULT: Tumor regression was seen in all patients; as TRG1 in 6 (30%), TRG2 in 2 (10%), TRG3 in 3 (15%), and TRG4 in 9 (45%). The median nodal harvest was 4 (range (0-12) in the NAT group vs 9 (range 1-19) in the control (P = 0.001). The median size of the largest lymph node was 5 mm (range 2-12 mm) in the NAT group vs 9 mm (range 4-15 mm) in the control group (P = 0.004). Tumor-positive nodes were identified in 4 of 17 of the NAT group patients and in 9 of the 20 controls (P = 0.308). CONCLUSION: Although NAT down-stages rectal cancer, it results in a significantly low yield of lymph nodes, which are also significantly smaller than those in nonirradiated controls. Therefore, surgeons and histopathologists must ensure adequate sampling and accurate staging is done for patients with irradiated rectal cancer.Item Preoperative adjuvant radiation with chemotherapy for rectal cancer: its impact on stage of disease and the role of endorectal ultrasound(Springer International, 1996) Bernini, A.; Deen, K.I.; Madoff, R.D.; Wong, W.D.BACKGROUND: Preoperative adjuvant radiation combined with chemotherapy is a recent development in the management of patients with rectalcancer invading perirectal tissue and regional lymph nodes. This study was performed to assess the impact of preoperative adjuvant therapy in patients judged by endorectal ultrasound to have extramural invasion of rectal cancer and/or regional lymph node involvement on tumor regression in bowel wall and lymph nodes. The predictive value of ultrasound in staging wall penetration and lymph node involvement after preoperative adjuvanttherapy was also assessed. METHODS: Patients (n = 43) were selected by ultrasound to have preoperative irradiation (4,500-5,040 cGy over 5-6 weeks). In 30 patients this was combined with 5-fluorouracil, 370 mg/m(2), for 5 days in the first and last weeks of irradiation. Pretreatment ultrasound was compared with pathologic findings in the resected specimen in all patients. Twenty-one were assessed by ultrasound after adjuvant therapy and findings compared with histology. RESULTS: Downstaging was seen in 23 (53%) patients with wall invasion and in 23 (72%) of 32 patients with lymph node involvement. Overall, downstaging was achieved in 30 (70%). Positive predictive values of ultrasound after irradiation were 72% and 56% for wall penetration and lymph node status, respectively. Negative predictive values of ultrasound after irradiation were 100% and 82%, respectively. CONCLUSION: In the majority of patients with rectal cancer invading perirectal tissues or lymph nodes, lesions may be downstaged by preoperative adjuvant therapy. Endorectal ultrasound after adjuvant therapy for rectal cancer is of a lesser predictive value chiefly because of overstaging.