Biomedical subjects

Edward Yu

Publications and source records attributed to Edward Yu.

At least 19 recordsLinked to original sources

PubMed2006

The effect of timing of radiotherapy after breast-conserving surgery in patients with positive or close resection margins, young age, and node-negative disease, with long term follow-up.

PURPOSE: The aim of this study was to determine the effect of timing of radiotherapy after conservative breast surgery on local recurrence in women with positive resection margins and young age, treated without systemic therapy. METHODS AND MATERIALS: A total of 568 patients with T1 and T2, N0 breast cancer were treated with breast-conserving surgery and breast irradiation, between January 1, 1985, and December 31, 1992, at the London Regional Cancer Centre. 63 patients (11.1%) had positive/close resection margins (< 2 mm) and 48 patients (8.4%) were age < or = 40 years. For patients with positive resection margins, the time intervals from breast surgery to breast irradiation used for analysis were, 0 to 8 weeks, > 8 to 12 weeks and > 12 weeks. For patients < or = 40 years, the intervals used for analysis were 0 to 8 weeks and > 8 weeks. RESULTS: Median follow up was 11.2 years. For patients < or = 40 years, local recurrence rate at 5 and 10 years was 17.2% and 19.8% respectively. Four patients (17.4%) treated in the 0-week to 8-week interval and 7 patients (28.0%) treated in the > 8 week interval had local recurrences. For patients < or = 40 years with positive resection margins, the local recurrence rate was 25.0%. For patients with positive resection margins, 5-year and 10-year local recurrence rates were as follows: 0 to 8 weeks, 0% and 10.5% respectively; > 8 to 12 weeks, 10.3% and 10.3% respectively; and > 12 weeks, 13.3% and 20.0% respectively. CONCLUSION: Patients < or = 40 years have an increased local recurrence rate which occurs early. Patients with positive resection margins have higher local recurrence rates that become apparent when breast irradiation is delayed.

Adult↗

PubMed2006

The role of radiation therapy in malignant pleural mesothelioma: a systematic review.

INTRODUCTION: Radiation therapy may offer patients presenting with malignant pleural mesothelioma (MPM) symptom palliation and improvements in quality of life. This systematic review will address the role of radiation therapy in the management of MPM. METHODS: A thorough systematic search of the literature was conducted for published articles and conference proceedings for applicable abstracts. Relevant trials were selected and assessed. RESULTS: Three small randomized controlled trials compared prophylactic external beam radiation therapy to no radiation therapy for patients with thoracic tracts caused by drainage tubes or diagnostic procedures. None of those trials reported any serious adverse effects. A pooled analysis found no significant reduction in the frequency of procedure tract metastases. Four non-comparative studies have shown that hemithoracic irradiation alone resulted in significant toxicity, including radiation-induced pulmonary fibrosis, radiation pneumonitis, and bronchopleural fistula, without any survival benefit. Few of the identified studies reported on symptom control, and no studies included formal measures of quality of life. CONCLUSION: There is limited evidence for the role of radiotherapy in the management of patients with MPM. Future studies including radiotherapy for the treatment of such patients should include formal measures of quality of life and symptom control.

Clinical Trials as Topic↗

PubMed2006

Syndrome of inappropriate antidiuretic hormone secretion (SIADH) in patients with limited stage small cell lung cancer.

A few series in the literature were published before 1987 on syndrome of inappropriate antidiuretic hormone secretion (SIADH) in small cell lung cancer (SCLC). This study examines the outcome in more recent era. From 1981-1998, there were 1417 new cases of SCLC diagnosed in the provincial registry, of which 244 were of limited stage (LS). A chart review and statistical analyses were performed using Mann-Whitney test, chi-square test and Kaplan-Meier method. Fourteen LS patients (group A) had SIADH at presentation. Group B consisted of 230 LS patients without SIADH. There were more patients with poorer performance status (ECOG 2-4) in group A than B (28.6% versus 7.8%, P=0.03). Otherwise, sex, age at diagnosis, nodal spread, pleural effusion, bronchial obstruction, superior vena cava obstruction, performance status, weight loss, and lactic dehydrogenase at presentation, were comparable between the two groups. Treatments given, e.g., extent of surgical resection (if performed, whether complete/incomplete), total number of chemotherapy cycles, radiotherapy doses, were comparable (P>0.05). The response to chemo-radiation was not significantly different (P=0.7). Five-year overall survival (8% versus 19%, P=0.08), and cause-specific survival (16% versus 20%, P=0.13) showed that group A patients had a worse outcome, though of borderline significance. Symptoms related to SIADH included: weakness, 4 patients; tiredness, 3; change in level of consciousness, 1; seizure, 1. The range of lowest sodium level was 110-129. Two patients also had paraneoplastic myopathy. SIADH resolved in 12 patients at 1.6-44.7 weeks (median: 4.3). Among the 14 patients who initially presented with SIADH and recurred later, 10 had recurrence of SIADH at the time of tumor recurrence. Serum sodium was useful for post-treatment surveillance in SCLC patients who presented with SIADH, with 71% (10/14) developing SIADH again at the time of recurrence. SIADH is a poor prognostic factor for LS SCLC.

Aged↗

PubMed2006

Comparative planning evaluation of intensity-modulated radiotherapy techniques for complex lung cancer cases.

BACKGROUND AND PURPOSE: Lung cancer treatment can be one of the most challenging fields in radiotherapy. The aim of the present study was to compare different modalities of radiation delivery based on a balanced scoring scheme for target coverage and normal tissue avoidance. PATIENTS AND METHODS: Treatment plans were developed for 15 patients with stage III inoperable non-small cell lung cancer using 3D conformal technique and intensity-modulated radiotherapy (IMRT). Elective nodal irradiation was included for all cases to create the most challenging scenarios with large target volumes. A 2 cm margin was used around the gross tumour volume (GTV) to generate PTV2 and 1cm margin around elective nodes for PTV1 resulting in PTV1 volumes larger than 1000 cm(3) in 13 of the 15 patients. 3D conformal and IMRT plans were generated on a commercial treatment planning system (TheraPlan Plus, Nucletron) with various combinations of beam energies and gantry angles. A 'dose quality factor' (DQF) was introduced to correlate the plan quality with patient specific parameters. RESULTS: A good correlation was found between the quality of the plans and the overlap between PTV1 and lungs. The patient feature factor (PFF), which is a product of several pertinent characteristics, was introduced to facilitate the choice of a particular technique for a particular patient. CONCLUSIONS: This approach may allow the evaluation of different treatment options prior to actual planning, subject to validation in larger prospective data sets.

Carcinoma, Non-Small-Cell Lung↗

PubMed2005

Eleven-year follow-up results in the delay of breast irradiation after conservative breast surgery in node-negative breast cancer patients.

PURPOSE: This retrospective review was conducted to determine if delay in the start of radiotherapy after conservative breast surgery had any detrimental effect on local recurrence or disease-free survival in node-negative breast cancer patients. METHODS AND MATERIALS: A total of 568 patients with T1 and T2, N0 breast cancer were treated with breast-conserving surgery and breast irradiation, without adjuvant systemic therapy, between January 1, 1985 and December 31, 1992 at the London Regional Cancer Centre. The time intervals from definitive breast surgery to breast irradiation used for analysis were 0 to 8 weeks (201 patients), greater than 8 to 12 weeks (235 patients), greater than 12 to 16 weeks (91 patients), and greater than 16 weeks (41 patients). Kaplan-Meier estimates of time to local-recurrence and disease-free survival rates were calculated. RESULTS: Median follow-up was 11.2 years. Patients in all 4 time intervals were similar in terms of age and pathologic features. No statistically significant difference was seen between the 4 groups in local recurrence or disease-free survival with surgery radiotherapy interval (p = 0.521 and p = 0.222, respectively). The overall local-recurrence rate at 5 and 10 years was 4.6% and 11.3%, respectively. The overall disease-free survival at 5 and 10 years was 79.6% and 67.0%, respectively. CONCLUSION: This retrospective study suggests that delay in the start of breast irradiation of up to 16 weeks from definitive surgery does not increase the risk of recurrence in node-negative breast cancer patients. The certainty of these results is limited by the retrospective nature of this analysis.

Adult↗

PubMed2005

Short- and long-term cause-specific survival of patients with inflammatory breast cancer.

BACKGROUND: Inflammatory breast cancer (IBC) had been perceived to have a poor prognosis. Oncologists were not enthusiastic in the past to give aggressive treatment. Single institution studies tend to have small patient numbers and limited years of follow-up. Most studies do not report 10-, 15- or 20-year results. METHODS: Data was obtained from the population-based database of the Surveillance, Epidemiology, and End Results program of the National Cancer Institute from 1975-1995 using SEER*Stat5.0 software. This period of 21 years was divided into 7 periods of 3 years each. The years were chosen so that there was adequate follow-up information to 2000. ICD-O-2 histology 8530/3 was used to define IBC. The lognormal model was used for statistical analysis. RESULTS: A total of 1684 patients were analyzed, of which 84% were white, 11% were African Americans, and 5% belonged to other races. Age distribution was < 30 years in 1%, 30-40 in 11%, 40-50 in 22%, 50-60 in 24%, 60-70 in 21%, and > 70 in 21%. The lognormal model was validated for 1975-77 and for 1978-80, since the 10-, 15- and 20-year cause-specific survival (CSS) rates, could be calculated using the Kaplan-Meier method with data available in 2000. The data were then used to estimate the 10-, 15- and 20-year CSS rates for the more recent years, and to study the trend of improvement in survival. There were increasing incidences of IBC: 134 patients in the 1975-77 period to 416 patients in the 1993-95 period. The corresponding 20-year CSS increased from 9% to 20% respectively with standard errors of less than 4%. CONCLUSION: The improvement of survival during the study period may be due to introduction of more aggressive treatments. However, there seem to be no further increase of long-term CSS, which should encourage oncologists to find even more effective treatments. Because of small numbers of patients, randomized studies will be difficult to conduct. The SEER population-based database will yield the best possible estimate of the trend in improvement of survival for patients with IBC.

Adult↗

PubMed2005

Minimum follow-up time required for the estimation of statistical cure of cancer patients: verification using data from 42 cancer sites in the SEER database.

BACKGROUND: The present commonly used five-year survival rates are not adequate to represent the statistical cure. In the present study, we established the minimum number of years required for follow-up to estimate statistical cure rate, by using a lognormal distribution of the survival time of those who died of their cancer. We introduced the term, threshold year, the follow-up time for patients dying from the specific cancer covers most of the survival data, leaving less than 2.25% uncovered. This is close enough to cure from that specific cancer. METHODS: Data from the Surveillance, Epidemiology and End Results (SEER) database were tested if the survival times of cancer patients who died of their disease followed the lognormal distribution using a minimum chi-square method. Patients diagnosed from 1973-1992 in the registries of Connecticut and Detroit were chosen so that a maximum of 27 years was allowed for follow-up to 1999. A total of 49 specific organ sites were tested. The parameters of those lognormal distributions were found for each cancer site. The cancer-specific survival rates at the threshold years were compared with the longest available Kaplan-Meier survival estimates. RESULTS: The characteristics of the cancer-specific survival times of cancer patients who died of their disease from 42 cancer sites out of 49 sites were verified to follow different lognormal distributions. The threshold years validated for statistical cure varied for different cancer sites, from 2.6 years for pancreas cancer to 25.2 years for cancer of salivary gland. At the threshold year, the statistical cure rates estimated for 40 cancer sites were found to match the actuarial long-term survival rates estimated by the Kaplan-Meier method within six percentage points. For two cancer sites: breast and thyroid, the threshold years were so long that the cancer-specific survival rates could yet not be obtained because the SEER data do not provide sufficiently long follow-up. CONCLUSION: The present study suggests a certain threshold year is required to wait before the statistical cure rate can be estimated for each cancer site. For some cancers, such as breast and thyroid, the 5- or 10-year survival rates inadequately reflect statistical cure rates, and highlight the need for long-term follow-up of these patients.

Disease-Free Survival↗

PubMed2005

Long-term survival rates of laryngeal cancer patients treated by radiation and surgery, radiation alone, and surgery alone: studied by lognormal and Kaplan-Meier survival methods.

BACKGROUND: Validation of the use of the lognormal model for predicting long-term survival rates using short-term follow-up data. METHODS: 907 cases of laryngeal cancer were treated from 1973-1977 by radiation and surgery (248), radiation alone (345), and surgery alone (314), in registries of Connecticut and Metropolitan Detroit of the SEER database, with known survival status up to 1999. Phase 1 of this study used the minimum chi-square test to assess the goodness of fit of the survival times of those who died with disease to a lognormal distribution. Phase 2 used the maximum likelihood method to estimate long-term survival rates using short-term follow-up data. In order to validate the lognormal model, the estimated long-term cancer-specific survival rates (CSSR) were compared with the values calculated by the Kaplan-Meier (KM) method using long-term data. RESULTS: The 25-year CSSR were predicted to be 72%, 68% and 65% for treatments by radiation and surgery, by radiation alone, and by surgery alone respectively, using short-term follow-up data by the lognormal model. Corresponding results calculated by the KM method were: 72+/-3%, 68+/-3% and 66+/-4% respectively. CONCLUSIONS: The lognormal model was validated for the prediction of the long-term survival rates of laryngeal cancer patients treated by these different methods. The lognormal model may become a useful tool in research on outcomes.

Adult↗

PubMed2004

Survival of patients with metastatic breast cancer: twenty-year data from two SEER registries.

BACKGROUND: Many researchers are interested to know if there are any improvements in recent treatment results for metastatic breast cancer in the community, especially for 10- or 15-year survival. METHODS: Between 1981 and 1985, 782 and 580 female patients with metastatic breast cancer were extracted respectively from the Connecticut and San Francisco-Oakland registries of the Surveillance, Epidemiology, and End Results (SEER) database. The lognormal statistical method to estimate survival was retrospectively validated since the 15-year cause-specific survival rates could be calculated using the standard life-table actuarial method. Estimated rates were compared to the actuarial data available in 2000. Between 1991 and 1995, further 752 and 632 female patients with metastatic breast cancer were extracted respectively from the Connecticut and San Francisco-Oakland registries. The data were analyzed to estimate the 15-year cause-specific survival rates before the year 2005. RESULTS: The 5-year period (1981-1985) was chosen, and patients were followed as a cohort for an additional 3 years. The estimated 15-year cause-specific survival rates were 7.1% (95% confidence interval, CI, 1.8-12.4) and 9.1% (95% CI, 3.8-14.4) by the lognormal model for the two registries of Connecticut and San Francisco-Oakland respectively. Since the SEER database provides follow-up information to the end of the year 2000, actuarial calculation can be performed to confirm (validate) the estimation. The Kaplan-Meier calculation for the 15-year cause-specific survival rates were 8.3% (95% CI, 5.8-10.8) and 7.0% (95% CI, 4.3-9.7) respectively. Using the 1991-1995 5-year period cohort and followed for an additional 3 years, the 15-year cause-specific survival rates were estimated to be 9.1% (95% CI, 3.8-14.4) and 14.7% (95% CI, 9.8-19.6) for the two registries of Connecticut and San Francisco-Oakland respectively. CONCLUSIONS: For the period 1981-1985, the 15-year cause-specific survival for the Connecticut and the San Francisco-Oakland registries were comparable. For the period 1991-1995, there was not much change in survival for the Connecticut registry patients, but there was an improvement in survival for the San Francisco-Oakland registry patients.

Adult↗

PubMed2004

Planning evaluation of radiotherapy for complex lung cancer cases using helical tomotherapy.

Lung cancer treatment is one of the most challenging fields in radiotherapy. The aim of the present study was to investigate what role helical tomotherapy (HT), a novel approach to the delivery of highly conformal dose distributions using intensity-modulated radiation fan beams, can play in difficult cases with large target volumes typical for many of these patients. Tomotherapy plans were developed for 15 patients with stage III inoperable non-small-cell lung cancer. While not necessarily clinically indicated, elective nodal irradiation was included for all cases to create the most challenging scenarios with large target volumes. A 2 cm margin was used around the gross tumour volume (GTV) to generate primary planning target volume (PTV2) and 1 cm margin around elective nodes for secondary planning target volume (PTV1) resulting in PTV1 volumes larger than 1000 cm3 in 13 of the 15 patients. Tomotherapy plans were created using an inverse treatment planning system (TomoTherapy Inc.) based on superposition/convolution dose calculation for a fan beam thickness of 25 mm and a pitch factor between 0.3 and 0.8. For comparison, plans were created using an intensity-modulated radiation therapy (IMRT) approach planned on a commercial treatment planning system (TheraplanPlus, Nucletron). Tomotherapy delivery times for the large target volumes were estimated to be between 4 and 19 min. Using a prescribed dose of 60 Gy to PTV2 and 46 Gy to PTV1, the mean lung dose was 23.8+/-4.6 Gy. A 'dose quality factor' was introduced to correlate the plan outcome with patient specific parameters. A good correlation was found between the quality of the HT plans and the IMRT plans with HT being slightly better in most cases. The overlap between lung and PTV was found to be a good indicator of plan quality for HT. The mean lung dose was found to increase by approximately 0.9 Gy per percent overlap volume. Helical tomotherapy planning resulted in highly conformal dose distributions. It allowed easy achievement of two different dose levels in the target simultaneously. As the overlap between PTV and lung volume is a major predictor of mean lung dose, future work will be directed to control of margins. Work is underway to investigate the possibility of breath-hold techniques for tomotherapy delivery to facilitate this aim.

Carcinoma, Non-Small-Cell Lung↗

PubMed2004

Radiation treatment of lung cancer--patterns of practice in Canada.

BACKGROUND AND PURPOSE: To assess the patterns of practice among Canadian radiation oncologists who treat lung cancers. PATIENTS AND METHODS: A questionnaire detailing different aspects of radiation treatment of lung cancer was mailed to all radiation oncologists treating lung cancer in Canada. Seventy-two percent (74/103) of radiation oncologists who treat lung cancer from all 34 Canadian cancer centres replied to the questionnaire. RESULTS: (a) Radiotherapy regimens in Canadian cancer centres are in accordance with several major randomised studies. There is still some variation in treatment practice that may be due to unresolved controversies or limited resources. The most frequently used prescription dose was 40Gy/15f/3w (where f stands for fractions and w stands for weeks) for small cell lung cancer (SCLC) and 60Gy/30f/6w for non-small cell lung cancer (NSCLC). If there were no resource constraints, 30% (22/74) and 20% (15/74) would prefer to use a different dose-fractionation scheme for SCLC and NSCLC, respectively; 95% (70/74) would prefer to use 3D-conformal or intensity-modulated radiotherapy. (b) Among the various modern technologies assessed by respondents, CT (computed tomography) simulator, multi-leaf collimator, on-line electronic portal imaging and PET (positron-emission tomography) scanning were rated the highest in terms of potential patient benefit. Discrepancy between demand and availability of technology was greatest for PET scanning. CONCLUSIONS: Canadian practice in the treatment of lung cancers shows some variations although it is consistent with the trends in the literature. The lack of some modern technologies and human resources is an ongoing concern, especially the lack of PET imaging equipment.

Adult↗

PubMed2004

Prediction of radiation pneumonitis by dose - volume histogram parameters in lung cancer--a systematic review.

BACKGROUND AND PURPOSE: To perform a systematic review of the predictive ability of various dose-volume histogram (DVH) parameters (V(dose), mean lung dose (MLD), and normal tissue complication probability (NTCP)) in the incidence of radiation pneumonitis (RP) caused by external-beam radiation therapy. METHODS AND MATERIALS: Studies assessing the relationship between CT-based DVH reduction parameters and RP rate in radically treated lung cancer were eligible for the review. Synonyms for RP, lung cancer, DVH and its associated parameters (NTCP, V(20), V(30), MLD) were combined in a search strategy involving electronic databases, secondary reference searching, and consultation with experts. Individual or group data were abstracted from the various reports to calculate operating characteristics and odds ratios for the different DVH metrics. RESULTS: A total of 12 published studies and two abstracts were identified. Eleven studies assessed V(dose), seven assessed MLD, and eight assessed NTCP. Nine studies exclusively analyzed the association between various DVH metrics and RP risk. Five studies also analyzed other patient, tumor, and treatment variables in conjunction with standard DVH metrics. A direct comparison between studies and the generation of summary statistics (i.e. meta-analysis) could not be achieved due to significant predictive and outcome variable heterogeneity. Most studies did show an association between DVH parameters and RP risk. However, overall accuracy, sensitivity, specificity, and positive predictive value were generally poor to fair for all three classes of DVH metrics. CONCLUSIONS: An association between DVH parameters and RP risk has been demonstrated in the literature. However, the ideal DVH metric with excellent operating characteristics, either alone or in a model with other predictive variables, for RP risk prediction has not yet been identified. Several recommendations for reporting and conduct of future research into the association between DVH metrics and RP risk are provided.

Carcinoma, Non-Small-Cell Lung↗

PubMed2004

Is extended volume external beam radiation therapy covering the anastomotic site beneficial in post-esophagectomy high risk patients?

BACKGROUND AND PURPOSE: To assess the impact of extended volume radiation therapy (RT) with anastomotic coverage on local control in high risk post-operative esophageal cancer patients. PATIENTS AND METHODS: This is a retrospective study of high risk (T(3), T(4), nodes positive, with or without margin involvement) post-operative esophageal cancer patients treated at London Regional Cancer Centre from 1989 to 1999. After esophagectomy, all patients received adjuvant combined modality therapy consisting of four cycles of fluorouracil-based chemotherapy, and loco-regional RT with or without coverage of the anastomotic site. RT dose ranged from 45 to 60 Gy at 1.8-2.0 Gy/fraction with treatment fields tailored to the pathologic findings and location of the anastomosis. CT planning was used in all patients to design spinal cord sparing beam arrangements. First relapse rate (first incidence of an event), disease specific survival and overall survival were calculated by Chi-Square, Log-Rank, and Kaplan-Meier (K-M) methods. RESULTS: During the study period, 72 patients had underwent esophagectomy and were considered for adjuvant chemoradiation therapy. Three patients were excluded due to disease progression prior to therapy. The 69 remaining patients formed the study cohort for the present analysis. The median age of the study group was 60 years (range 35-82 years). Pathologic stage distribution (AJCC 1997 staging) was T(2,3) N(1) in 94% patients, 65% of the cases were adenocarcinoma and had undergone transhiatal esophagectomy (86%) with positive/close margins in 34 (49%) patients. Median follow-up was 30.5 months (range 3.4-116.3 months). Two- and 5-year actuarial overall survivals rates were 50 and 31%, respectively. First relapse rate after adjuvant therapy was 63.7% (n = 44) and median time to relapse was 27.2 months. Anastomosis recurrence rates were 29% with small volume and 0% with extended volume RT (P = 0.041). Local and regional relapse occurred in 74.2% of patients treated with small volume RT compared to 15.4% in patients treated with extended volume RT (P < 0.001). After adjusting for resection margin status, the local control benefit of extended volume RT remained significant (P = 0.003). Treatment interruptions and late gastrointestinal toxicity were not significantly increased with the use of extended volume RT. CONCLUSIONS: A significant decrease in local and regional relapse without added late toxicity was achieved with the use of extended volume RT encompassing the anastomotic site post-operatively in high risk esophageal cancer patients.

Adult↗

PubMed2004

Astigmatism outcomes of horizontal temporal versus nasal clear corneal incision cataract surgery.

PURPOSE: To compare the short- and long-term astigmatism outcomes after cataract surgery using temporal clear horizontal corneal incisions and nasal horizontal clear corneal incisions. SETTING: Wilmer Eye Institute, Johns Hopkins Hospital, Baltimore, Maryland, USA. METHODS: This retrospective study included a consecutive series of eyes having phacoemulsification with implantation of a 6.0 mm foldable acrylic intraocular lens through a 3.5 mm horizontal clear corneal incision at 180 degrees (temporal incision in right eyes, nasal incision in left eyes). Astigmatism was measured by keratometry readings before surgery and 6 weeks and 12 months postoperatively. RESULTS: The mean preoperative astigmatism in the 178 eyes (94 right, 84 left) of 161 patients was 0.78 diopter (D); 54.5% of eyes had against-the-rule (ATR) astigmatism, 22.5% had with-the-rule (WTR) astigmatism, and 14.0% were astigmatically neutral. A significant shift toward WTR astigmatism occurred postoperatively. At 6 weeks, 48.3% of eyes had WTR astigmatism and 23.0% had ATR astigmatism. At 12 months, 43.8% had WTR astigmatism and 25.8% had ATR astigmatism. Vector analysis revealed a mean surgically induced astigmatism (SIA) of 1.17 D at 6 weeks and 1.04 D at 12 months. The side of the incision significantly affected SIA. At 6 weeks, temporal incisions yielded a mean SIA of 0.74 D and the nasal incisions, of 1.65 D. This trend in SIA persisted at 12 months: 0.71 D for temporal incisions and 1.41 D for nasal incisions. CONCLUSIONS: Cataract surgery using a horizontal clear corneal incision induced WTR astigmatism 6 weeks and 12 months postoperatively. Temporal incisions induced significantly less astigmatism than nasal incisions.

Aged↗

PubMed2003

Patterns of breast recurrence in a pilot study of brachytherapy confined to the lumpectomy site for early breast cancer with six years' minimum follow-up.

PURPOSE: In this pilot study of high-dose-rate brachytherapy to the lumpectomy site as the sole radiation, ipsilateral and contralateral breast recurrences are documented with specific attention to the location of recurrence relative to the lumpectomy site. METHODS: Between March 1992 and January 1996, 39 patients with T1 (32 patients) and T2 breast cancers received 37.2 Gy in 10 fractions (b.i.d.) over 1 week prescribed to a volume encompassing the surgical clips. Thirteen received adjuvant tamoxifen, and 4 received chemotherapy. Follow-up included annual bilateral mammograms and clinical breast examination every 3 to 6 months. Whereas 13 patients had intraoperative implantation of the lumpectomy site, 26 had postoperative implantation. The latter group and 7 of the former group had surgical clips marking the lumpectomy site, which allowed estimates of the distance of any ipsilateral breast recurrence from the lumpectomy site, using the mediolateral and cranio-caudad mammographic views. RESULTS: At a median follow-up of 91 months, 33 women are alive, 4 have died of disease, and 2 have died of other causes. The 5-year actuarial rate of ipsilateral breast recurrence was 16.2%. Of 6 ipsilateral recurrences, 2 occurred within the lumpectomy site (in-field recurrences). One of the 2 patients had a 1-mm microscopic margin at initial diagnosis; the recurrence was a 3.5-mm microscopic focus of duct carcinoma in situ. The other patient had a 1.5-cm, high-grade infiltrating mammary carcinoma with no residual at wider resection at first diagnosis; the 5-mm invasive recurrence was also of high grade. Four women developed invasive recurrences at least 1.6 cm or more from the lumpectomy site (out-of-field recurrences). Two of these women had gross multifocal recurrences with two cancers in each patient; 1 of the 2 patients had an extensive intraductal component at initial diagnosis. The estimated nearest distances between the out-of-field recurrences and the surgical clips were 1.6, 5.5, 7.7, and 12.0 cm. All ipsilateral breast recurrences were salvaged by mastectomy (4 patients) or by repeat lumpectomy (2 patients) and whole-breast radiation. The interval postdiagnosis to ipsilateral recurrence ranged from 20 months to 58 months. There were two contralateral breast recurrences at intervals of 34 and 36 months; 1 of these patients also had a multifocal, ipsilateral recurrence at 58 months, as previously described. Among patients with any breast recurrence, 1 patient had a family history of prostate cancer; there was no family history of breast or ovarian cancer. Of 17 patients who received adjuvant systemic therapy, only 1 had a breast recurrence. CONCLUSIONS: In this pilot study, breast recurrences outside of the lumpectomy site were the predominant pattern of recurrence.

Adult↗

PubMed2003

Twenty-year follow-up study of long-term survival of limited-stage small-cell lung cancer and overview of prognostic and treatment factors.

PURPOSE: To predict the long-term survival results of clinical trials earlier than using actuarial methods and to assess the factors predictive of long-term cure in patients with limited-stage small-cell lung cancer. METHODS AND MATERIALS: Between 1981 and 1998, 1417 new cases of small-cell lung cancer were diagnosed in Saskatchewan, Canada, of which 244 were limited stage and treated with curative intent. They were followed to the end of February 2002. A parametric lognormal statistical model was retrospectively validated to determine whether long-term survival rates could be estimated several years earlier than is possible using the standard life-table actuarial method. RESULTS: The survival time of the uncured group followed a lognormal distribution. Four 2-year periods of diagnosis were combined, and patients were followed as a cohort for an additional 2 years. The estimated 10-year cause-specific survival rate was 13% by the lognormal model. The Kaplan-Meier calculation for 10-year cause-specific survival rate was 15% +/- 3%. The data also showed that the absence of mediastinal lymphadenopathy and higher chest radiotherapy dose were significant prognostic factors on multivariate analysis (p < 0.05). Among the 163 patients given prophylactic cranial irradiation, a higher biologically effective dose to the brain did not improve survival or decrease the incidence of brain metastases. CONCLUSION: The lognormal model has been validated for the estimation of survival in patients with limited-stage small-cell lung cancer. A higher biologically effective dose to the brain did not improve survival or decrease the incidence of brain metastases.

Algorithms↗

PubMed2002

Improving the consistency in cervical esophageal target volume definition by special training.

PURPOSE: Three-dimensional conformal radiation therapy requires the precise definition of the target volume. Its potential benefits could be offset by the inconsistency in target definition by radiation oncologists. In a previous survey of radiation oncologists, a large degree of variation in target volume definition of cervical esophageal cancer was noted for the boost phase of radiotherapy. The present study evaluated whether special training could improve the consistency in target volume definitions. METHODS AND MATERIALS: A pre-training survey was performed to establish baseline values. This was followed by a special one-on-one training session on treatment planning based on the RTOG 94-05 protocol to 12 radiation oncologists. Target volumes were redrawn immediately and at 1-2 months later. Post-training vs. pre-training target volumes were compared. RESULTS: There was less variability in the longitudinal positions of the target volumes post-training compared to pre-training (p < 0.05 in 5 of 6 comparisons). One case had more variability due to the lack of a visible gross tumor on CT scans. Transverse contours of target volumes did not show any significant difference pre- or post-training. CONCLUSION: For cervical esophageal cancer, this study suggests that special training on protocol guidelines may improve consistency in target volume definition. Explicit protocol directions are required for situations where the gross tumor is not easily visible on CT scans. This may be particularly important for multicenter clinical trials, to reduce the occurrences of protocol violations.

Education, Medical, Continuing↗

PubMed2002

Prophylactic cranial irradiation revisited: cost-effectiveness and quality of life in small-cell lung cancer.

PURPOSE: To investigate the therapeutic usefulness and cost-effectiveness of prophylactic cranial irradiation (PCI) in patients with limited-stage small-cell lung cancer (SCLC) who had achieved a complete remission. METHODS: A retrospective chart review was undertaken of all patients diagnosed in Saskatchewan with SCLC between 1987 and 1998 inclusive. Patients who achieved a complete remission were divided into two groups, depending on whether they underwent PCI (PCI+ and PCI-, respectively). The quality-of-life-adjusted survival was estimated by the Q-TWiST method (quality time without symptoms and toxicity). The mean incremental costs per month of incremental OS were calculated in a cost-effectiveness analysis. RESULTS: Among the 98 complete remission patients, the median OS for PCI+ and PCI- patients was 20.0 and 19.0 months, respectively (p > 0.05, nonsignificant). The median disease-free survival was 14.7 and 10.0 months, respectively (p < 0.05). The difference in the mean Q-TWiST survival was significant (p < 0.01). The mean marginal cost was $18,834/PCI+ patient and $17,885/PCI- patient (p > 0.05, nonsignificant). The cost-effectiveness ratio was $70/mo of incremental OS if u(tox) and u(rel) (the utility coefficients to reflect the value of time in health states of toxicity and relapse) were assumed to be 1.0. CONCLUSION: PCI is a cost-effective treatment that improves the quality-of-life-adjusted survival for patients with a complete remission of SCLC.

Aged↗