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Biomedical subjects

N C Choi

Publications and source records attributed to N C Choi.

At least 19 recordsLinked to original sources
PubMed2000

Stage III thymoma: pattern of failure after surgery and postoperative radiotherapy and its implication for future study.

PURPOSE: With the conventional approach of surgery and postoperative radiotherapy for patients with Masaoka Stage III thymoma, progress has been slow for an improvement in the long-term survival rate over the past 20 years. The objective of this study was to evaluate the pattern of failure and survival after surgery and postoperative radiotherapy in Stage III thymoma and search for a new direction for better therapy outcome. METHODS AND MATERIALS: Between 1975 and 1993, 111 patients with thymoma were treated at Massachusetts General Hospital. Of these, 32 patients were determined to have Masaoka Stage III thymoma. The initial treatment included surgery for clinically resectable disease in 25 patients and preoperative therapy for unresectable disease in 7 patients. Surgical procedure consisted of thymectomy plus resection of involved tissues. For postoperative radiotherapy (n = 23), radiation dose consisted of 45-50 Gy for close resection margins, 54 Gy for microscopically positive resection margins, and 60 Gy for grossly positive margins administered in 1.8 to 2.0 Gy of daily dose fractions, 5 fractions a week, over a period of 5 to 6.6 weeks. In preoperative radiotherapy, a dose of 40 Gy was administered in 2.0 Gy of daily dose fractions, 5 days a week. For patients with large tumor requiring more than 30% of total lung volume included in the target volume (n = 3), a preoperative radiation dose of 30 Gy was administered and an additional dose of 24-30 Gy was given to the tumor bed region after surgery for positive resection margins. RESULTS: Patients with Stage III thymoma accounted for 29% (32/111 patients) of all patients. The median age was 57 years with a range from 27 to 81 years; gender ratio was 10:22 for male to female. The median follow-up time was 6 years. Histologic subtypes included well-differentiated thymic carcinoma in 19 (59%), high-grade carcinoma in 6 (19%), organoid thymoma in 4 (13%), and cortical thymoma in 3 (9%) according to the Marino and Müller-Hermelink classification. The overall survival rates were 71% and 54% at 5 and 10 years, respectively. Ten of the 25 patients who were subjected to surgery as initial treatment were found to have incomplete resection by histopathologic evaluation. The 5- and 10-year survival rates were 86% and 69% for patients (n = 15) with clear resection margins as compared with 28% and 14% for those (n = 10) with incomplete resection margins even after postoperative therapy, p = 0.002. Survival rates at 5 and 10 years were 100% and 67% for those with unresectable disease treated with preoperative radiation (n = 6) and subsequent surgery (n = 3). Recurrence was noted in 12 of 32 patients and 11 of these died of recurrent thymoma. Recurrences at pleura and tumor bed accounted for 77% of all relapses, and all pleural recurrences were observed among the patients who were treated with surgery initially. CONCLUSION: Incomplete resection leads to poor results even with postoperative radiotherapy or chemoradiotherapy in Stage III thymoma. Pleural recurrence is also observed more often among patients treated with surgery first. These findings suggest that preoperative radiotherapy or chemoradiotherapy may result in an increase in survival by improving the rate of complete resection and reducing local and pleural recurrences.

Adult↗
PubMed2000

Triphasic perfusion computed tomography in acute middle cerebral artery stroke: a correlation with angiographic findings.

OBJECTIVE: To evaluate the usefulness of triphasic perfusion computed tomography (TPCT) in diagnosing middle cerebral artery (MCA) occlusion and in assessing the perfusion deficit and collateral circulation in patients with acute ischemic stroke. BACKGROUND: Conventional angiography is the criterion standard for the diagnosis of MCA occlusion and for the assessment of perfusion deficit and collateral blood supply. The risk of hemorrhagic transformation after recanalization of occluded arteries by thrombolytic therapy is considered high when pretherapeutic residual flow is markedly reduced. PATIENTS AND METHODS: In 8 patients within 3 hours of onset of acute MCA stroke, precontrast computed tomographic scans were taken, and then TPCT was performed after power-injector controlled intravenous administration of contrast media. Sequential images of early, middle, and late phases were obtained. The whole procedure took 5 minutes. Perfusion deficit on TPCT was graded as "severe" or "moderate," depending on the state of collateral flow. Digital subtraction angiography (DSA) was performed in all patients within 6 hours of acute stroke. Direct intra-arterial urokinase infusion was begun immediately after the angiographic superselection of the MCA occlusion site in 6 of the 8 patients within 7 hours of onset (range, 4.3-6.2 hours). RESULTS: The DSA findings showed occlusion of the MCA stem (n = 1) and at the bifurcation (n = 4). The sites of proximal MCA occlusion could be identified on the early and middle images of TPCT in all 5 patients. On DSA findings, all 8 patients had a zone of perfusion deficit with markedly slow leptomeningeal collaterals and a zone of perfusion deficit with no collaterals. The zone of severe perfusion deficit on TPCT corresponded to the zone of perfusion deficit with no or few collaterals on angiography, and the zone of moderate perfusion deficit on TPCT corresponded to that of perfusion deficit with markedly slow leptomeningeal collaterals. Early parenchymal hypoattenuation on precontrast computed tomography was confined to the zone of severe perfusion deficit on TPCT. The initial National Institutes of Health Stroke Scale score correlated better with the total extent of severe perfusion deficit and moderate perfusion deficit on TPCT than that of severe perfusion deficit alone. After direct intra-arterial thrombolysis within 7 hours of onset, symptomatic hemorrhagic transformation did not develop in 4 patients with small severe perfusion deficit (33% or less of the presumed MCA territory). However, the remaining 2 patients with large severe perfusion deficit (more than 50% of the presumed MCA territory) deteriorated to death with hemorrhagic transformation. CONCLUSIONS: Triphasic perfusion computed tomography is useful for diagnosing proximal MCA occlusion and assessing perfusion deficit and collateral circulation as reliably as DSA. The zone of severe perfusion deficit on TPCT may be presumed to be the ischemic core, and that of moderate perfusion deficit, the penumbra zone. Triphasic perfusion computed tomography may be used as a rapid and noninvasive tool to make thrombolysis safer.

Acute Disease↗
PubMed2000

Correlative assessment of hemodynamic parameters obtained with T2*-weighted perfusion MR imaging and SPECT in symptomatic carotid artery occlusion.

BACKGROUND AND PURPOSE: Perfusion MR imaging and single-photon emission CT (SPECT) are commonly used to evaluate hemodynamic status in patients with symptomatic occlusive cerebrovascular disease. These techniques rely on different underlying physiological mechanisms, and the data may not correspond. We studied the relationship between hemodynamic parameters obtained with these two methods. METHODS: We performed perfusion MR imaging and SPECT in 10 patients with symptomatic unilateral internal carotid artery occlusion. Relative cerebral blood volume (rCBV) and uncorrected mean transit time (uMTT) were obtained with dynamic contrast-enhanced T2*-weighted MR imaging. Relative cerebral blood flow (rCBF) and vascular reserve capacity were measured with 99mTc-HMPAO SPECT; vascular reserve capacity was calculated by the difference in CBF before and after acetazolamide challenge. Ratios of these hemodynamic parameters between the affected and contralateral vascular territories were calculated and compared. RESULTS: Normal-to-increased CBV, prolonged uMTT, decreased CBF, and normal-to-diminished vascular reserve capacity were observed in the affected vascular territories. Reduction of vascular reserve capacity corresponded well with uMTT but not with CBF and CBV. CBF, CBV, and uMTT did not correspond to one another. CONCLUSION: uMTT is more sensitive than the other parameters in estimating vascular reserve capacity. The relationship between parameters obtained with perfusion MR imaging and SPECT should be considered in assessing the hemodynamic status of patients with symptomatic occlusive cerebrovascular disease.

Aged↗
PubMed1999

Superior sulcus lung tumors: impact of local control on survival.

OBJECTIVES: Our goal was to assess patient survival and response to treatment for superior sulcus tumors treated with combined radiation therapy and surgery when possible, or with radiation alone when surgery was not possible. METHODS: Seventy-three patients were treated for primary non-small cell carcinoma of the superior pulmonary sulcus. Thirty-four patients received combined resection and irradiation. Thirty-nine patients who had extensive primary disease, distant metastases, or who were medically unfit for surgery were treated with radiation alone. Thirty-one patients (91%) assigned to the resection/irradiation group completed treatment. Combined therapy patients routinely received 40 Gy before the operation, with additional postoperative irradiation based on the surgical findings. RESULTS: Overall survival at 5 years was 19% and disease-specific survival was 20% for all patients. Overall survival and disease-specific survival at 5 years for the resection/irradiation group were 33% and 38%, respectively. Significant indicators of poor prognosis included unresected primary disease, low performance score, T4 stage, or positive node status. Eighty-two percent of the patients who received irradiation alone were treated with palliative intent. Freedom from local-regional progression, achieved initially in 66% of these patients, was associated with a median survival of 8 months. Median survival for 7 patients considered for definitive irradiation was 25 months. During the first 18 months, distant failures occurred in approximately 35% of patients in each treatment group. CONCLUSIONS: Selection of medically fit patients with resectable disease for combined surgery and aggressive radiation therapy resulted in a high likelihood of local control. Overall survival for the resection/irradiation group was significantly poorer for patients with T4 stage, nodal disease, or Horner's syndrome. Distant metastases eventually developed in 56% of patients undergoing resection. Median survival in the resection/irradiation group was significantly prolonged for those patients who could tolerate high-dose radiation treatment.

Carcinoma, Non-Small-Cell Lung↗
PubMed1999

Various patterns of perfusion-weighted MR imaging and MR angiographic findings in hyperacute ischemic stroke.

BACKGROUND AND PURPOSE: Various clinical subtypes of patients presenting with sudden-onset ischemic stroke have been recognized, but classification of those types is not simple. We identified various patterns of perfusion-weighted MR imaging and MR angiographic findings in hyperacute ischemic stroke with relation to clinical outcomes. METHODS: Twelve patients with symptoms of acute ischemic stroke due to middle cerebral artery occlusion underwent perfusion-weighted MR imaging and MR angiography within 6 hours after the onset of symptoms. Perfusion-weighted imaging was performed with a conventional dynamic contrast-enhanced T2*-weighted sequence, and cerebral blood volume (CBV) maps were then created. CBV maps and MR angiographic findings were compared with 99mTc-HMPAO brain SPECT scans, short-term outcomes, and follow-up imaging findings. RESULTS: The combined CBV and MR angiographic findings were classified into three patterns: arterial occlusion and decreased CBV (n = 8), arterial occlusion and increased CBV (n = 2), and no arterial occlusion and normal CBV (n = 2). These three patterns were strongly related to SPECT findings, short-term outcomes, and follow-up imaging findings. Perfusion on SPECT decreased markedly in the affected regions in all patients with the first pattern, decreased slightly in the second pattern, and was normal in the third pattern. Symptoms were not significantly changed at 24 hours after onset in any of the patients with the first pattern, but resolved completely in all patients with the latter two patterns. Follow-up imaging showed large infarctions in all patients with the first pattern. Initially, no infarction was seen in the second pattern, but watershed infarction developed later in one of these patients. CONCLUSION: Hyperacute ischemic stroke may be differentiated into three imaging patterns with different clinical outcomes. The combined use of perfusion-weighted MR imaging and MR angiography may play a substantial role in guiding the choice of treatment of this disease.

Acute Disease↗
PubMed1998

Phase I study to determine the maximum-tolerated dose of radiation in standard daily and hyperfractionated-accelerated twice-daily radiation schedules with concurrent chemotherapy for limited-stage small-cell lung cancer.

PURPOSE: An improvement in radiation dose schedule is necessary to increase local tumor control and survival in limited-stage small-cell lung cancer. The goal of this study was to determine the maximum-tolerated dose (MTD) of radiation (RT) in both standard daily and hyperfractionated-accelerated (HA) twice-daily RT schedules in concurrent chemoradiation. METHODS: The study design consisted of a sequential dose escalation in both daily and HA twice-daily RT regimens. RT dose to the initial volume was kept at 40 to 40.5 Gy, while it was gradually increased to the boost volume by adding a 7% to 11 % increment of total dose to subsequent cohorts. The MTD was defined as the radiation dose level at one cohort below that which resulted in more than 33% of patients experiencing grade > or = 4 acute esophagitis and/or grade > or = 3 pulmonary toxicity. The study plan included nine cohorts, five on HA twice-daily and four on daily regimens for the dose escalation. Chemotherapy consisted of three cycles of cisplatin 33 mg/m2/d on days 1 to 3 over 30 minutes, cyclophosphamide 500 mg/m2 on day 1 intravenously (IV) over 1 hour, and etoposide 80 mg/m2/d on days 1 to 3 over 1 hour every 3 weeks (PCE) and two cycles of PE. RT was started at the initiation of the fourth cycle of chemotherapy. RESULTS: Fifty patients were enrolled onto the study. The median age was 60 years (range, 38-79), sex ratio 2.3:1 for male to female, weight loss less than 5% in 73%, and performance score 0 to 1 in 94% and 2 in 6% of patients. In HA twice-daily RT, grade > or = 4 acute esophagitis was noted in two of five (40%), two of seven (29%), four of six (67%), and five of six patients (86%) at 50 (1.25 Gy twice daily), 45, 50, and 55.5 Gy in 1.5 Gy twice daily, 5 d/wk, respectively. Grade > or = 3 pulmonary toxicity was not seen in any of these 24 patients. Therefore, the MTD for HA twice-daily RT was judged to be 45 Gy in 30 fractions over 3 weeks. In daily RT, grade > or = 4 acute esophagitis was noted in zero of four, zero of four, one of five (20%), and two of six patients (33%) at 56, 60, 66, and 70 Gy on a schedule of 2 Gy per fraction per day, five fractions per week. Grade > or = 3 pneumonitis was not observed in any of the 19 patients. Thus, the MTD for daily RT was judged to be at least 70 Gy in 35 fractions over 7 weeks. Grade 4 granulocytopenia and thrombocytopenia were observed in 53% and 6% of patients, respectively, during the first three cycles of PCE. During chemotherapy cycles 4 to 5, grade 4 granulocytopenia and thrombocytopenia were noted in 43% and 29% of patients at 45 Gy in 30 fractions over 3 weeks (MTD) by HA twice-daily RT and 50% and 17% at 70 Gy in 35 fractions over 7 weeks (MTD) by daily RT, respectively. The overall tumor response consisted of complete remission (CR) in 51% (24 of 47), partial remission (PR) in 38% (1 8 of 47), and stable disease in 2% (one of 47). The median survival time of all patients was 24.4 months and 2- and 3-year survival rates were 53% and 28%, respectively. With regard to the different radiation schedules, 2- and 3-year survival rates were 52% and 25% for the HA twice-daily and 54% and 35% for the daily RT cohorts. CONCLUSION: The MTD of HA twice-daily RT was determined to be 45 Gy in 30 fractions over 3 weeks, while it was judged to be at least 70 Gy in 35 fractions over 7 weeks for daily RT. A phase III randomized trial to compare standard daily RT with HA twice-daily RT at their MTD for local tumor control and survival would be a sensible research in searching for a more effective RT dose-schedule than those that are being used currently.

Adult↗
PubMed1998

Temporal pattern of blood volume change in cerebral infarction: evaluation with dynamic contrast-enhanced T2*-weighted MR imaging.

OBJECTIVE: The purposes of this study were to evaluate the temporal pattern of blood volume change in cerebral infarction and to provide a guideline in the interpretation of blood volume data, which are known to vary according to the stage of infarction. SUBJECTS AND METHODS: Thirty-three patients with large middle cerebral infarctions were examined one to three times (one time in 20 patients, two times in eight patients, and three times in five patients) after the onset of stroke by dynamic contrast-enhanced T2*-weighted MR imaging and MR angiography. A total of 54 infarctions (29 in an acute stage [up to 7 days], 15 in a subacute stage [8-21 days], and 10 in a chronic stage [22-35 days]) were included. After blood volume maps were created, blood volume ratios (blood volume of the infarcted region divided by blood volume of corresponding contralateral region) were compared at different stages. Likewise, findings on MR angiography were compared at different stages. RESULTS: Mean blood volume ratios in each stage of infarction were 0.46 in the acute stage, 1.48 in the subacute stage, and 0.73 in the chronic stage (p < .001). Recanalization of occluded arteries occurred in 21% of infarctions in the acute stage and 80% in the subacute stage. Infarctions with recanalization had higher blood volume ratios than did those without recanalization (p < .001). A biphasic pattern of blood volume ratios was found in 13 patients who underwent at least two MR examinations: increased blood volume in the subacute stage and decreased blood volume in the chronic stage, regardless of recanalization (p < .01). CONCLUSION: Blood volume that initially decreases in cerebral infarction increases in the subacute stage, reflecting reperfusion hyperemia. Blood volume decreases again in the chronic stage. The time interval between onset of stroke and MR examination must be considered for correct interpretation of blood volume data in cerebral infarction at various stages.

Adolescent↗
PubMed1997

Induction therapy for esophageal cancer with paclitaxel and hyperfractionated radiotherapy: a phase I and II study.

OBJECTIVE: Induction chemoradiotherapy followed by surgery may improve survival rates among patients with esophageal carcinoma. We designed a novel intense induction regimen with paclitaxel and high-dose hyperfractionated radiotherapy to maximize complete response rates. METHODS: Forty patients with esophageal cancer were treated in a phase I and II trial of induction chemotherapy (cisplatin, 5-fluorouracil, and paclitaxel) at three dosage levels (75, 125, and 100 mg/m2) and concurrent hyperfractionated radiotherapy (45 Gy to the mediastinum, 58.5 Gy to the tumor). The mean age was 62 years, and 32 patients (80%) had adenocarcinoma. Twenty-eight of 40 (70%) patients had locally advanced tumors (T3, or stage IIB or greater). RESULTS: The average hospitalization for induction treatment was 17 days. Toxicity was substantial, with esophagitis necessitating nutritional support the most common complication. The maximum tolerated dose of paclitaxel was 100 mg/m2. Two patients died during induction treatment. Thirty-six patients (90%) underwent resection. The median length of stay was 10 days, and two patients died after the operation. Fourteen of 36 patients (39%) had a pathologic complete response. Patients who received all prescribed chemotherapy had a higher pathologic complete response rate (50%) than did patients who required dose reduction (17%; p = 0.076). The 2-year survival rate was 61% (95% CI 35% to 86%) with a median follow-up of 11.9 months. CONCLUSIONS: Paclitaxel at a dose of 100 mg/m2 appears to have acceptable toxicity. The high pathologic complete response rate in this regimen is encouraging, but it is associated with substantial toxicity. The toxicity of this regimen is not acceptable and will require substantial reduction in the radiation component. Survival data are too short-term to confirm enhanced survival.

Adenocarcinoma↗
PubMed1997

Potential impact on survival of improved tumor downstaging and resection rate by preoperative twice-daily radiation and concurrent chemotherapy in stage IIIA non-small-cell lung cancer.

PURPOSE: The main objectives of this study were (a) to ascertain the feasibility and toxicity of preoperative twice-daily radiation therapy and concurrent chemotherapy, surgery, and postoperative therapy in stage IIIA (N2) non-small-cell lung cancer (NSCLC), and (b) to evaluate tumor response, resection rate, pathologic tumor downstaging, and survival. METHODS: Eligibility included biopsy-proven N2 lesion (stage IIIA) by mediastinoscopy, Karnofsky performance score > or = 70, and weight loss less than 5% in the 3 months before diagnosis. The treatment program consisted of two courses of preoperative cisplatin, vinblastine, and fluorouracil (5-FU); 42 Gy concurrent radiation at 1.5 Gy per fraction in two fractions per day; surgery on day 57; and one more course of postoperative chemotherapy and 12 to 18 Gy of concurrent twice-daily radiation. RESULTS: Forty-two patients with stage IIIA (N2) NSCLC (27 men and 15 women, age 38 to 77 years) were enrolled onto this prospective study. Forty of 42 patients tolerated the intended dose (42 Gy) of preoperative radiation and 37 of 39 resected patients received prescribed postoperative radiation. The intended dose of chemotherapy was given in 100%, 70%, and 60% of patients for the first, second, and third courses of chemotherapy. Marked dysphagia that required intravenous hydration was noted in 14% of patients (six of 42). Myelotoxicities included grade > or = 3 granulocytopenia in 23% and thrombocytopenia in 6% of 113 chemotherapy courses. Febrile neutropenia that required hospital admission was noted in 9% of 113 chemotherapy courses. Surgical resection was performed in 93% of patients. Treatment-related mortality was noted in 7% of patients. The overall survival rates by the Kaplan-Meier method were 66%, 37%, and 37% at 2,3, and 5 years, respectively, with a median follow-up time of 48 months. Pathologic examination of the surgical specimen showed a downward shift in tumor extent from stage IIIA (N2) to stage II (N1) in 33%, to stage I (NO) in 24% (10 of 42), and to stage 0 (TONO) in 9.5%, for a total of 67%. The degree of tumor downstaging was also translated into a survival benefit: 5-year survival rates from the time of surgery were 79%, 42%, and 18% for postoperative tumor stages 0 and I, II, and III, respectively (P = .04). CONCLUSION: Concurrent chemoradiotherapy using twice-daily radiation is an effective induction regimen that resulted in 67% tumor downstaging, and an encouraging 37% 5-year survival rate. The degree of tumor downstaging may be a useful intermediate end point for survival benefit in stage IIIA (N2) NSCLC.

Adult↗
PubMed1996

Simplified measurement of deoxyglucose utilization rate.

UNLABELLED: The reliability of the dose uptake ratio (DUR), a widely used index of 18F-fluoro-2-deoxy-D-glucose (18FDG) metabolism in a variety of tumors, depends on the overall rate of removal of 18FDG from the circulation. Correcting for this factor is important if DUR is to be used quantitatively for pre- and post-treatment assessments of tumors. METHODS: We developed a simplified kinetic method (SKM), based on measured blood curves from a control group, which requires one venous blood sample. We compared the simplified method to the conventional kinetic method and the widely used DUR index in 13 patients with grade 3 or 4 non-small-cell lung carcinoma. Studies were obtained before and after treatment. In all patients, dynamic PET imaging and blood activity measurement was performed for 80 min. The utilization rate of 18FDG (MRDGlc) was calculated by using a three-compartment model and correlated with a 55-min measurement of DUR and with the simplified kinetic method. RESULTS: Coefficients of determination (R2) between MRDGlc and DUR before and after treatment were 0.53 and 0.71, respectively. Using the SKM, these values improved significantly (p < 0.0001) to 0.96 and 0.94, respectively. The pooled pre- and post-treatment coefficient of determination for DUR versus MRDGlc was 0.81; for SKM, it improved significantly (p < 0.001) to 0.98. CONCLUSION: These results indicate that the observed tumor tissue uptake of 18FDG, corrected for blood 18FDG activity and glucose concentration, can reliably predict glucose metabolic rate from a single static image acquired at between 45 min and 1 hr after injection. This has substantial implications for the quantitative use of 18FDG PET to diagnose and manage malignancy.

Blood Glucose↗
PubMed1994

Evolution of treatment strategies for adenocarcinoma of the esophagus and gastroesophageal junction.

Between 1980 and 1988, 91 patients with adenocarcinoma of the esophagus were treated by surgical resection and selective postoperative therapy. Operative mortality was 2%. Pathologic stage was I in 4, II in 26, and III in 61. Actuarial 2- and 5-year survival was 24% and 8%. From 1987 to 1989, 16 patients with adenocarcinoma of the esophagus were treated with two cycles of 5-fluorouracil and cisplatin followed by surgical resection. There was 1 complete response (6%), 5 partial responses (31%), and 10 with no response (63%). Twelve patients had resection. Pathologic stage was I in 1, II in 4, and III in 8. There was one chemotherapy-related death and one surgical death. Actuarial 4-year survival is 42%. From 1990 to 1993, 22 patients with adenocarcinoma of the esophagus were treated with two cycles of etoposide, doxorubicin, and cisplatin followed by surgical resection. There was 1 complete response (5%), 11 partial responses (50%), and 10 with no response (45%). Eighteen patients had resection. Pathologic stage was 0 in 1, II in 8, and III in 9. There were no treatment-related deaths. The actuarial 2-year survival is 58%. Conclusions are necessarily limited because the patients were not treated in a randomized fashion. These preliminary results with preoperative chemotherapy appear improved (p = 0.04 and p = 0.004, respectively) as compared with results from 1980 to 1988 without preoperative chemotherapy.

Adenocarcinoma↗
PubMed1994

Toxicity of thoracic radiotherapy on pulmonary function in lung cancer.

Physiological changes in pulmonary function (PF) as a result of radiation therapy (RT) or radiation therapy plus chemotherapy (RT + CT) for unresectable lung cancer were evaluated in an ongoing prospective study and an attempt was also made to define a guideline which can be used to minimize adverse effect of RT on pulmonary function before RT is given. The study design consisted of: (a) standard overall pulmonary function test (PFT); (b) regional PFT, i.e. a quantitative analysis of regional distribution of ventilation, perfusion and volume using 13N and a positron camera before RT; and (c) follow-up studies of standard PFT every 6 months for 3 years after RT or RT + CT. Predicted post-RT PF prior to RT was calculated by a formula: predicted FEV1 after RT = FEV1 before RT x (1 - an average of the percent of ventilation and perfusion contributed by lung tissue within the RT treatment volume). A total of 267 patients with unresectable, but still potentially curable lung cancer by RT were entered into this study, and 135 patients who were free of recurrence underwent repeat studies. Loss of PF as a result of RT is closely related to the degree of PF reserve prior to RT. Patients with FEV1 > 50% of the predicted showed a statistically significant decrease in FEV1, FVC, MBC, peak expiratory flow rate and DLCO, i.e. a 22% loss of the initial value. Airway resistance was increased by 31%. Two-thirds of this group of patients showed a decrease in PF as predicted by the above formula. For patients with limited PF reserve defined by FEV1 < 50% of the predicted, the pattern of PF loss after RT was quite different. An improvement in PF although it was < or = 10%, contrary to the prediction, was noted in 50% of patients, and another 37% of patients showed a small decrease in PF (< or = 10% of the initial value). Only 13% of patients showed a loss of pulmonary function as predicted by regional PF data. Patients with a significant shift (> 10%) of ventilation and/or perfusion to the uninvolved side of the lung by centrally located primary tumor or involved lymph nodes showed an increase in PF in 60% of patients after RT, and another 20% of patients showed a minor decrease in PF (< 10% of the initial value). Only 20% of these patients showed a decrease in pulmonary function as predicted by regional PF data. Guidelines for minimizing adverse effect of RT on PF, which are based on the initial PF reserve and regional PF data, are presented.

Aged↗
PubMed1994

The dose uptake ratio as an index of glucose metabolism: useful parameter or oversimplification?

UNLABELLED: The dose uptake ratio (DUR) has been used as a quantitative index of glucose metabolism for tumor classification and monitoring response to treatment. In order to provide consistent results, DUR measurements should be made when the concentration of tracer has reached a plateau. The time of this plateau cannot be identified from a single static acquisition. METHODS: In this study, we investigated the changes in DUR as a function of time in eight patients with stage III lung cancer. All patients underwent a quantitative dynamic 18F-FDG PET study before and after treatment and the data were analyzed with a three-compartment model. Using the fitted model parameters, the DUR was predicted at the plateau and intermediate times. RESULTS: Tumor concentrations of 18F-FDG did not reach a plateau within the 90 min of imaging in any of the pre-treatment studies and only in one case post-treatment. The average time to reach 95% of the plateau value pre-treatment was 298 +/- 42 min (range: 130-500 min); in post-treatment, it was 154 +/- 31 min (range: 65-240 min). The difference between the plateau DUR and the 60-min value was 46% +/- 6% pre-treatment and 17% +/- 5% post-treatment. CONCLUSIONS: These data indicate that DUR can vary widely with the time of measurement and that DUR should be interpreted with caution in any individual patient.

Blood Glucose↗
PubMed1993

Long-term follow-up of neoadjuvant chemotherapy with 5-fluorouracil and cisplatin with surgical resection and possible postoperative radiotherapy and/or chemotherapy in squamous cell carcinoma of the esophagus.

Seventy patients with local squamous cell carcinoma of the esophagus were treated between 1981 and 1990 with preoperative chemotherapy, surgical resection, and possible postoperative radiation therapy and/or chemotherapy. Chemotherapy included two cycles of 5-fluorouracil (1000 mg/m2) by continuous intravenous infusion on days 1-4 and cisplatin (100 mg/m2) on day 4. Complete clinical response (CCR) was achieved in 28 (41%) patients, partial clinical response (PCR) in 17 (25%), and no response in 23 (34%). Fifty-five (81%) patients were resected, 6 (9%) were explored, and 7 (10%) were unable to have surgery. Microscopic analysis of 55 resected patients showed 50 (91%) with active tumor, 1 (2%) with necrotic tumor, and 4 (7%) with a pathological complete response to chemotherapy. Twenty-six of the 55 resected patients (47%) had no gross evidence of disease at the time of surgical inspection. Median overall survival was 21.86 months (range 2-107 months) for all patients and 26.71 months (range 2-107 months) for resected patients. Actuarial 5-year survival rate was 31% for all patients and 39% for resected patients. Prolonged survival correlates with complete clinical response to chemotherapy, low pathological stage of disease, and successful resection of the lesion.

Adult↗
PubMed1993

Lung tumor metastasis to breast detected by fluorine-18-fluorodeoxyglucose PET.

We report a case of breast metastasis from a large-cell bronchogenic adenocarcinoma. Serial 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) was used to monitor the response of the primary lesion to radiation therapy. In the 7-wk interval between studies, an area of markedly increased FDG uptake appeared in the right breast. On subsequent biopsy this proved to be a metastatic deposit from the primary lesion. breast metastasis is uncommon. The ability of FDG-PET to detect metastatic lesions from primary lung tumor is variable. In this case, the finding of the new breast lesion resulted in introduction of chemotherapy to the treatment program.

Breast Neoplasms↗