Long-term risk of cardiovascular disease in 5-year survivors of testicular cancer.

PURPOSE: To evaluate the long-term risk of cardiovascular disease (CVD) in survivors of testicular cancer (TC). PATIENTS AND METHODS: We compared CVD incidence in 2,512 5-year survivors of TC, who were treated between 1965 and 1995, with general population rates. Treatment effects on CVD risk were quantified in multivariate Cox regression analysis. RESULTS: After a median follow-up of 18.4 years, 694 cardiovascular events occurred, including 141 acute myocardial infarctions (MIs). The standardized incidence ratio (SIR) for coronary heart disease was 1.17 (95% CI, 1.04 to 1.31), with 14 excess cases per 10,000 person-years. The SIR for MI was significantly increased in nonseminoma survivors with attained ages of less than 45 (SIR = 2.06) and 45 to 54 years (SIR = 1.86) but significantly decreased for survivors with attained ages of 55 years or older (SIR = 0.53). In Cox analysis, mediastinal irradiation was associated with a 3.7-fold (95% CI, 2.2- to 6.2-fold) increased MI risk compared with surgery alone, whereas infradiaphragmatic irradiation was not associated with an increased MI risk. Cisplatin, vinblastine, and bleomycin (PVB) chemotherapy (CT) was associated with a 1.9-fold (95% CI, 1.7- to 2.0-fold) increased MI risk, and bleomycin, etoposide, and cisplatin (BEP) CT was associated with a 1.5-fold (95% CI, 1.0- to 2.2-fold) increased CVD risk and was not associated with increased MI risk (hazard ratio = 1.2; 95% CI, 0.7 to 2.1). Recent smoking was associated with a 2.6-fold (95% CI, 1.8- to 3.9-fold) increased MI risk. CONCLUSION: Nonseminomatous TC survivors experience a moderately increased MI risk at young ages. Physicians should be aware of excess CVD risk associated with mediastinal radiotherapy, PVB CT, and recent smoking. Intervention in modifiable cardiovascular risk factors is especially important in TC survivors. Whether BEP treatment increases CVD risk should be evaluated after more prolonged follow-up.

Reduction of observer variation using matched CT-PET for lung cancer delineation: a three-dimensional analysis.

PURPOSE: Target delineation using only CT information introduces large geometric uncertainties in radiotherapy for lung cancer. Therefore, a reduction of the delineation variability is needed. The impact of including a matched CT scan with 2-[18F]fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) and adaptation of the delineation protocol and software on target delineation in lung cancer was evaluated in an extensive multi-institutional setting and compared with the delineations using CT only. METHODS AND MATERIALS: The study was separated into two phases. For the first phase, 11 radiation oncologists (observers) delineated the gross tumor volume (GTV), including the pathologic lymph nodes of 22 lung cancer patients (Stages I-IIIB) on CT only. For the second phase (1 year later), the same radiation oncologists delineated the GTV of the same 22 patients on a matched CT-FDG-PET scan using an adapted delineation protocol and software (according to the results of the first phase). All delineated volumes were analyzed in detail. The observer variation was computed in three dimensions by measuring the distance between the median GTV surface and each individual GTV. The variation in distance of all radiation oncologists was expressed as a standard deviation. The observer variation was evaluated for anatomic regions (lung, mediastinum, chest wall, atelectasis, and lymph nodes) and interpretation regions (agreement and disagreement; i.e., >80% vs. <80% of the radiation oncologists delineated the same structure, respectively). All radiation oncologist-computer interactions were recorded and analyzed with a tool called "Big Brother." RESULTS: The overall three-dimensional observer variation was reduced from 1.0 cm (SD) for the first phase (CT only) to 0.4 cm (SD) for the second phase (matched CT-FDG-PET). The largest reduction in the observer variation was seen in the atelectasis region (SD 1.9 cm reduced to 0.5 cm). The mean ratio between the common and encompassing volume was 0.17 and 0.29 for the first and second phases, respectively. For the first phase, the common volume was 0 in 4 patients (i.e., no common point for all GTVs). In the second phase, the common volume was always >0. For all anatomic regions, the interpretation differences among the radiation oncologists were reduced. The amount of disagreement was 45% and 18% for the first and second phase, respectively. Furthermore, the mean delineation time (12 vs. 16 min, p<0.001) and mean number of corrections (25 vs. 39, p<0.001) were reduced in the second phase compared with the first phase. CONCLUSION: For high-precision radiotherapy, the delineation of lung target volumes using only CT introduces too great a variability among radiation oncologists. Implementing matched CT-FDG-PET and adapted delineation protocol and software reduced observer variation in lung cancer delineation significantly with respect to CT only. However, the remaining observer variation was still large compared with other geometric uncertainties (setup variation and organ motion).

Observer variation in target volume delineation of lung cancer related to radiation oncologist-computer interaction: a 'Big Brother' evaluation.

BACKGROUND AND PURPOSE: To evaluate the process of target volume delineation in lung cancer for optimization of imaging, delineation protocol and delineation software. PATIENTS AND METHODS: Eleven radiation oncologists (observers) from five different institutions delineated the Gross Tumor Volume (GTV) including positive lymph nodes of 22 lung cancer patients (stages I-IIIB) on CT only. All radiation oncologist-computer interactions were recorded with a tool called 'Big Brother'. For each radiation oncologist and patient the following issues were analyzed: delineation time, number of delineated points and corrections, zoom levels, level and window (L/W) settings, CT slice changes, use of side windows (coronal and sagittal) and software button use. RESULTS: The mean delineation time per GTV was 16 min (SD 10 min). The mean delineation time for lymph node positive patients was on average 3 min larger (P = 0.02) than for lymph node negative patients. Many corrections (55%) were due to L/W change (e.g. delineating in mediastinum L/W and then correcting in lung L/W). For the lymph node region, a relatively large number of corrections was found (3.7 corr/cm2), indicating that it was difficult to delineate lymph nodes. For the tumor-atelectasis region, a relative small number of corrections was found (1.0 corr/cm2), indicating that including or excluding atelectasis into the GTV was a clinical decision. Inappropriate use of L/W settings was frequently found (e.g. 46% of all delineated points in the tumor-lung region were delineated in mediastinum L/W settings). Despite a large observer variation in cranial and caudal direction of 0.72 cm (1 SD), the coronal and sagittal side windows were not used in 45 and 60% of the cases, respectively. For the more difficult cases, observer variation was smaller when the coronal and sagittal side windows were used. CONCLUSIONS: With the 'Big Brother' tool a method was developed to trace the delineation process. The differences between observers concerning the delineation style were large. This study led to recommendations on how to improve delineation accuracy by adapting the delineation protocol (guidelines for L/W use) and delineation software (double window with lung and mediastinum L/W settings at the same time, enforced use of coronal and sagittal views) and including FDG-PET information (lymph nodes and atelectasis).