A decrease in the size of ground glass nodules may indicate the optimal timing for curative surgery

Objectives

Although ground glass nodules (GGNs) are generally considered to grow slowly to a large size, their natural progression remains unclear, and a decrease in tumor size has been reported in a few previous studies. The study aimed to retrospectively review the radiologic and pathological characteristics of resected ground glass nodules (GGNs) followed with chest computed tomography (CT) for at least a year before surgery to clarify the natural progression of GGNs.

Patients and methods

The chest CT cans and clinical charts of 32 GGNs in 31 patients who underwent pulmonary resection between January 2006 and March 2013 were retrospectively reviewed. The definitions of pure GGNs and part-solid nodules were based on the tumor shadow disappearance rate. The tumor size was measured twice, and the mean size was used for evaluation.

Results

The mean GGN size before surgery was 15.2 mm, and the median follow-up period before surgery was 21 months. In the follow-up period, 15 (58%) of 26 pure GGNs at the initial CT remained pure GGNs at the last CT. However, a solid component appeared in the remaining 11 tumors (42%) of the 26 initial pure GGNs. Furthermore, 1 GGN of the 15 GGNs that remained pure and 10 of the 11 GGNs with solid component also showed a size decrease. In addition, 6 part-solid nodules were observed at the initial CT. Of these, 3 showed a decrease in size during follow-up. Overall, 47% of the GGNs showed a size reduction on follow-up chest CT.

Conclusions

A size reduction was observed in nearly half of the GGNs and suggested the progression to an invasive adenocarcinoma. When a mild collapse of the GGNs is observed, a careful follow-up is necessary to identify a solid component. Tumor size decreases may represent the optimal timing of pulmonary resection for curative treatment.     

Does enhanced CT influence the biological GTV measurement on FDG-PET images?

Objectives

To test the influence of media injection in PET/CT on the functional or gross tumour volume measurement.

Patients and methods

Thirty-three patients (56 ± 19 years) with non-Hodgkin’s lymphoma (n = 22) or Hodgkin’s disease (n = 11) were prospectively studied at staging. PET/CTs were performed 60 min after injection of FDG. Iopamiron 300 (Iopamidol, 1.5 cc/kg) was injected immediately after, followed 50 s later by a second craniocaudal CT (CT+). PET images were successively reconstructed using the unenhanced CT (PET−) and the CT+ (PET+) for attenuation correction using iterative reconstruction (4 iterations, 8 subsets, 5 mm post-filtering). The SUV_max, SUV_mean, SUV_peak and functional tumoural volume were measured in tumoural lymphadenopathies or malignant tissues (n = 56 VOIs) using 5 3D-thresholding methods on PET− and PET+ images: absolute SUV value of 2.5; 40% of SUV_max, and 3 adaptative thresholding methods (Vauclin, Black and Schaefer methods).

Results

The SUV_mean and the volume measurement were significantly different (p < 0.001) for the five segmentation methods for PET− (p < 0.001) and PET+ (p < 0.001). The SUV_max, SUV_mean and SUV_peak increased significantly in PET+ compared to PET− (2–5%). The SUV_peak was not significantly different for the five segmentation methods. The functional volume measurements were significantly different between PET− and PET+ only for the 2.5 segmentation method (+3%; p = 0.001), but not for the 40%, Vauclin, Black and Schaefer methods.

Conclusion

The functional volume could be measured in PET/CT when CT was performed with enhanced media. Caution should be taken when using the volume delineation method. Volume delineation methods using absolute threshold may artefactually increase the functional volume when enhanced CT is used for attenuation correction. The delineation volume using the relative or adaptative method should be preferred when contrast media are used for PET/CT.     

Utility of Maximum CT Value in Predicting the Invasiveness of Pure Ground-Glass Nodules

PurposeTo predict the histologic invasiveness of pure GGNs using the maximum CT value.Patients and MethodsOne hundred eighty patients underwent a resection of pure GGNs. On preoperative CT imaging studies, we selected the axial section that showed the densest component of each GGN. The CT value was measured using a DICOM (Digital Imaging and Communication in Medicine) viewer, excluding portions of vessels and bronchi. The correlation between the CT value and GGN histologic diagnosis was analyzed.ResultsThe numbers of patients with atypical adenomatous hyperplasia, adenocarcinoma-in-situ (AIS), minimally invasive adenocarcinoma (MIA), and invasive adenocarcinoma (IAC) were 9, 108, 56, and 7, respectively. One of the IAC tumors exhibited lymphatic invasion, and there were no cases of vascular invasion. In comparison to preinvasive lesions (atypical adenomatous hyperplasia and AIS), invasive lesions (MIA and IAC) were correlated with a higher maximum CT value (−404 ± 113 Hounsfield units [HU] vs. −216 ± 125 HU, P < .01). The cutoff point of maximum CT value was determined at −300 HU using receiver operating characteristic curve analysis, and exhibited sensitivity and specificity of 83% and 88%, respectively. Multivariate analysis revealed that maximum CT value was an independent predictor of histologic invasiveness (odds ratio 39, P < .01). The interobserver reliability was satisfactory (intraclass correlation coefficient, 0.738; unweighted kappa-values, 0.722).ConclusionIAC and MIA accounted for 4% and 31% of the pure GGN lesions, respectively. Higher maximum CT value (≥ −300 HU) was a useful predictor of histologic invasiveness.     

Interferon α-2b gains high sustained response therapy for advanced essential thrombocythemia and polycythemia vera with JAK2V617F positive mutation

Objective

This open-label, prospective, observational study aimed to evaluate treatment response, efficacy therapy and safety to IFN α-2b for the essential thrombocythemia (ET) and polycythemia vera (PV) with JAK2V617F positive mutation.

Method

A total of 123 ET patients received IFNα-2b therapy with JAK2V617F positive or negative mutation; and 136 PV patients with JAK2V617F⁺ received IFNα-2b or hydroxyurea (HU) therapy according to random number assignment (ages 18–65 years old).

Result

ET patients receiving IFN α-2b with JAK2V617F⁺ had a greater advantage in overall hematologic response (OHR) than JAK2V617F⁻ (83.3% versus 61.4%, P < 0.01). For PV patients with JAK2V617F⁺, IFN had no OHR superiority to HU (70.3% versus 70.8%, P > 0.05), but which gained a greater satisfactory molecular response than HU (54.7% versus 19.4%, P < 0.01). IFN significantly decreased the phlebotomy rate, which was better than HU for MPDs patients with OHR than HU (3.6% versus 65.7%, P < 0.01). Furthermore, ET patients with JAK2V617F⁺ demonstrated a definite advantage over JAK2V617F⁻ in five-year PFS (75.9% versus 47.6%, P < 0.05). For PV patients with JAK2V617F⁺, IFN α-2b was superior to HU in five-year PFS (66.3% versus 46.7%, P < 0.01). Moreover, IFN α-2b also contributed to improved vasomotor symptoms in MPDs, and especially significantly decreased the incidence of distal paresthesias (14.1% versus 37.5%) and erythromelalgia (9.4% versus 29.2%) better than HU (P < 0.01). Meanwhile, IFN did not observe the severe hematological adverse events in patients with PV or ET.

Conclusion

The data confirmed that IFN α-2b benefited the patients with ET or PV, particularly for JAK2V617F⁺ mutation.     

The role of F-FDG PET/CT for evaluation of metastatic mediastinal lymph nodes in patients with lung squamous-cell carcinoma or adenocarcinoma

Objectives

To evaluate the efficacy of ¹⁸F-FDG PET/CT in depicting metastatic mediastinal lymph nodes in patients with lung squamous-cell carcinoma (LSCC) or lung adenocarcinoma (LAC) in a tuberculosis-endemic country.

Methods

This study retrospectively reviewed patients with LSCC or LAC, who underwent preoperative ¹⁸F-FDG PET/CT to assess mediastinal lymph node metastasis. Patients with the short-axis of mediastinal lymph node ≤ 15 mm were included. PET/CT interpretation was analyzed in two ways. Firstly, with CT for anatomical localization, lymph nodes showing greater ¹⁸F-FDG uptake than vessel pool on PET were regarded malignant. Secondly, lymph nodes with positive uptake on PET were considered malignant, only when nodes had neither calcification nor higher attenuation than vessel pool on CT.

Results

One hundred and sixteen LSCCs and 234 LACs were evaluated. With CT for anatomical localization, the sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) of PET were 78.6%, 45.5%, 53.4%, 31.4% and 87.0% in LSCC group, and 61.8%, 66.3%, 65.0%, 42.9% and 80.9% in LAC group. PET showed higher specificity and accuracy in LAC group compared with LSCC group (p = 0.001 and p = 0.038, respectively). Considering calcification or high attenuation on CT, the sensitivity, specificity, accuracy, PPV and NPV of PET/CT were 71.4%, 67.0%, 68.1%, 40.8% and 88.1% in LSCC group, and 54.4%, 86.1%, 76.9%, 61.7% and 82.2% in LAC group. Compared with PET, PET/CT possessed higher specificity and accuracy in LSCC group (p = 0.000 and p = 0.000, respectively), and higher specificity, accuracy and PPV in LAC group (p = 0.000, p = 0.000 and p = 0.022, respectively).

Conclusions

¹⁸F-FDG PET displays limited efficacy in assessing mediastinal lymph node metastasis with the short-axis diameter <15 mm in LSCC and LAC groups and higher false-positivity in LSCC group. The specificity and accuracy in LSCC and LAC groups are enhanced by interpreting attenuation characteristic on CT.     

The importance of actual tumor growth rate on disease free survival and overall survival in laryngeal squamous cell carcinoma

Background and purpose

Evaluation of the variation in tumor growth rate and the influence of tumor growth rate on disease free survival (DFS) and overall survival (OS) in laryngeal squamous cell carcinoma (LSCC).

Material and methods

We delineated tumor volume on a diagnostic and planning CT scan in 131 patients with laryngeal squamous cell carcinoma and calculated the tumor growth rate. Primary endpoint was DFS. Follow up data were collected retrospectively.

Results

A large variation in tumor growth rate was seen. When dichotomized with a cut-off point of −0.3 ln(cc/day), we found a significant association between high growth rate and worse DFS (p = 0.008) and OS (p = 0.013). After stepwise adjustment for potential confounders (age, differentiation and tumor volume) this significant association persisted. However, after adjustment of N-stage association disappeared. Exploratory analyses suggested a strong association between N-stage and tumor growth rate.

Conclusions

In laryngeal squamous cell carcinoma, there is a large variation in tumor growth rate. This tumor growth rate seems to be an important factor in disease free survival and OS. This tumor growth rate is independent of age, differentiation and tumor volume associated with DFS, but N-stage seems to be a more important risk factor.     

In vivo quality assurance of volumetric modulated arc therapy for ano-rectal cancer with thermoluminescent dosimetry and image-guidance

Objective

To assess in vivo dose distribution using cone-beam computed tomography scans (CBCTs) and thermoluminescent dosimeters (TLDs) in patients with anal or rectal cancer treated with volumetric modulated arc therapy (VMAT).

Methods

Intracavitary (IC) in vivo dosimetry (IVD) was performed in 11 patients using adapted endorectal probes containing TLDs, with extra measurements at the perianal skin (PS) for anal margin tumors. Measured doses were compared to calculated ones obtained from image fusion of CBCT with CT treatments plans.

Results

A total of 55 IC and 6 PS measurements were analyzed. IC TLD median planned and measured doses were 1.81 Gy (range, 0.25–2.02 Gy) and 1.82 Gy (range, 0.19–2.12 Gy), respectively. In comparison to the planned doses all IC TLD dose measurements differed by a median dose of 0.02 Gy (range, −0.11/+0.19 Gy, p = 0.102) (median difference of 1.1%, range −6.1%/+10.6%). Overall, 95% of IC measurements were within ±7.7% of the expected percentage doses and only 1 value was above +10%. For PS measurements, only one was not within ±7.7% of expected values (i.e., −8.9%).

Conclusions

Image guidance using CBCT for IVD with TLDs is helpful to validate the delivered doses in patients treated with VMAT for ano-rectal tumors.     

An assessment of the magnitude of intra-fraction movement of head-and-neck IMRT cases and its implication on the action-level of the imaging protocol

Background and purpose

A planning margin ?3 mm is employed in some head-and-neck IMRT cases due to the proximity of critical structures. This study aims to explore the need to redefine the action-level in the head-and-neck imaging protocol in consideration of the intra-fraction movement.

Material and methods

This is a local study of 18 patients treated using the same immobilisation system and setup protocol. Post-treatment orthogonal pair of kilovoltage X-ray images was acquired on the first three days of treatment. 106 sets of pre- and post-treatment kV X-ray images acquired over 53 fractions were analysed against the treatment planning DRR for calculation of intra-fraction movement.

Results

Individual mean intra-fraction movement in all directions ranged from −1.8 to 1.1 mm. Population mean (median) intra-fraction movement in the x-, y-, and z-planes were −0.1 mm (0 mm), −0.3 mm (−0.3 mm) and −0.2 mm (−0.2 mm) respectively. Intra-fraction movement in all three dimensions, x-, y- and z-planes were considered statistically significant (p < 0.05). 7 out of 53 fractions (13.2%) were highlighted as the combined magnitude of the intra-fraction motion with the uncorrected pre-treatment setup errors had exceeded the boundaries of given margins.

Conclusions

3 mm-AL was not adequate to account for intra-fraction movement when the CTV–PTV margin was ?3 mm and should be excluded from the routine imaging protocol and daily image-guided radiotherapy should be employed. Adjusting the action-level to 2 mm would allow a more confident approach in delivery of the prescribed dose in head-and-neck IMRT cases.     

Comparison between CT tumor size and pathological tumor size in frozen section examinations of lung adenocarcinoma

Objective

We examined the appropriate measurement for pathological tumor size by comparing radiological and pathological tumor size of resected lung adenocarcinoma in FSE.

Materials and methods

We reviewed records of 59 resected specimens of lung adenocarcinoma for FSE from January to December 2008. Specimens were well-inflated with saline by using an injector before cutting into segments. After selecting the tumor segment of maximal diameter, we compared three ways of measuring pathological tumor size by using paired t-test: (I) macroscopic tumor size (MTS), measured with a metal straight ruler, (II) microscopic frozen section tumor size (FSTS), and (III) microscopic paraffin section tumor size (PSTS). We compared each discrepancy rate (DR) [DR = (CT tumor size − pathological tumor size)/CT tumor size × 100] (%) between tumors that were air-containing type and solid-density type on CT scans, and also compared the tumors with lepidic component rates (LCR) ≥50% and LCR <50%, by using Mann–Whitney U-tests.

Results

FSE could diagnose malignancy with 100% accuracy. The mean CT tumor size was 18.36 mm, and the mean pathological tumor sizes (MTS, FSTS, and PSTS) were 17.81, 14.29, and 14.23 mm, respectively. FSTS and PSTS were significantly smaller than CT tumor size (p < 0.001). The DR calculated with PSTS was significantly larger in air-containing than in solid-density tumors, and also larger in LCR ≥50% than in LCR <50% tumors.

Conclusion

FSE with the inflation method diagnosed malignancy with 100% accuracy. The lung specimen must be sufficiently inflated to prevent tissue shrinking, and we propose MTS as the definition for pathological tumor size in FSE. The greater discordance observed between CT tumor size and microscopic tumor size was assumed to be due to shrinkage of the lepidic component in the tumor.     

High resolution CT in differentiating minimally invasive component in early lung adenocarcinoma

Objectives

To analyze high-resolution computed tomography (HRCT) appearances of early lung adenocarcinoma and evaluate HRCT in the differentiation of minimally invasive component in early lung adenocarcinoma.

Materials and methods

HRCT appearances of 140 nodules (less than 2 cm in diameter) of early lung adenocarcinoma were reviewed retrospectively. All these nodules were proven by surgery and pathology including 60 nodules of minimally invasive adenocarcinoma (MIA) and 80 nodules of preinvasive lesion (PL). HRCT features of two groups of lung nodules, including shape, margin, pattern, diameter, diameter of solid component, vascular changes, air bronchogram, vacuole, pleural indentation and multiplicity were analyzed and compared using univariate logistic regression analysis. Attenuation values of pure ground-glass nodule, pure ground-glass component and solid component of mixed ground-glass nodule were compared by using unpaired t-test or Wilcoxon rank-sum test.

Results

The statistically significant differences were found in shape, margin, pattern, diameter, diameter of solid component, pulmonary vein changes, air bronchogram and pleural indentation (Odds ratio [OR] = 3.115 [P = 0.001], OR = 3.754 [P = 0.011], OR = 9.815 [P = 0.000], OR = 1.306 [P = 0.000], OR = 1.361 [P = 0.031], OR = 6.971 [P = 0.000], OR = 6.167 [P = 0.000], OR = 2.296 [P = 0.027], respectively). The statistically significant difference was also found in attenuation value of solid component (t = 3.702, P = 0.000). By multivariate logistic analysis, attenuation value of solid component was significantly associated with MIA (OR = 1.005, P = 0.032). MIA was more often a larger, lobulated or irregular, mixed ground-glass nodule with a solid component larger than 5 mm, and higher attenuation values. In addition, MIA often had an abnormality in pulmonary vein, air bronchogram and pleural indentation.

Conclusions

HRCT can demonstrate the morphological features of early lung adenocarcinoma and identify minimally invasive component.     

A comparison of pancreaticoduodenectomy with pylorus preserving pancreaticoduodenectomy: A meta-analysis of 2822 patients

Background

The gold-standard for surgical excision of peri-ampullary tumours has not been established despite numerous studies, due to conflicting outcomes.

Aim

To consolidate the published evidence and compare outcomes between pancreaticoduodenectomy (PD) and pylorus preserving pancreaticoduodenectomy (PPPD) across all published comparative studies.

Methods

Using meta-analytical techniques the study compared: operative details, post-operative adverse events and survival following PD and PPPD. Comparative studies published between 1986 and 2005 of PD versus PPPD were included. A random effect model was employed, with significance reported at the 5% level.

Results

32 studies comprising 2822 patients (1335 PD and 1487 PPPD), including 5 randomized controlled trials with 421 patients (215 PD and 206 PPPD) were included. Patients undergoing PPPD were found to have smaller tumours (weighted mean difference (WMD) −0.54 cm, p = 0.030), although no significant difference in the number of patients with stage III or IV disease existed between the groups (odds ratio, OR 1.55, p = 0.320). Decreased operating times (WMD −41.3 min, p = 0.010) and fewer blood transfusions (WMD −0.9 units, p < 0.001) were observed in the PPPD group. There was no difference in post-operative complications, including pancreatic and biliary leaks or fistulae, between the two groups. It was suggested that peri-operative mortality was decreased in the PPPD group (OR 1.7, p = 0.040), and overall survival was better (hazard ratio (HR) 0.66, p = 0.02), although this did not remain significant on subgroup analysis.

Conclusions

Both PD and PPPD had similar peri-operative adverse events, however, in overall analysis PPPD has lower mortality and improved long-term patient survival, although this was not reflected in the sub-group analysis.     

Prediction of rectal lymph node metastasis by pelvic computed tomography measurement

Aim

Rectal cancer staging represents a crucial step to select the best treatment for this tumour. Particularly after neo-adjuvant chemoradiotherapy (CRT), it may influence the surgical procedure (e.g. radical resection vs. local excision). The aim of this study was to determine the best lymph node size cut-off at computed tomography (CT) to predict nodal metastasis in rectal cancer patients with and without preoperative CRT.

Methods

A consecutive series of patients operated on for primary mid–low rectal adenocarcinoma, all staged with pelvic CT scan, were subdivided as follows: those who underwent surgery alone treatment without CRT (Group A) and those who underwent preoperative CRT (Group B). All CT scans were re-viewed by a single radiologist and, based on the lymph node size, findings were compared with pathologic lymph node status (pN). At each lymph node size cut-off value, the following were calculated: accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV). The best cut-off value was defined as having an accuracy ≥70% with the highest NPV.

Results

The study population consisted of 162 patients: Group A (n = 52) and Group B (n = 110). Patients classified as pN-positive (n = 45) had a higher number of and larger sized lymph nodes by CT scan than patients classified as pN-negative (n = 117). The cut-off values with an accuracy ≥70% ranged between 7 and 11 mm in Group A and between 9 and 14 mm in Group B. The cut-off with the best NPV was 7 mm for Group A and 10 mm for Group B.

Conclusions

Acknowledging the limitations of the dimensional criterion, lymph node size cut-off values found in our study may be useful for planning rectal cancer treatment using CT scan.     

High-risk CT features for detection of local recurrence after stereotactic ablative radiotherapy for lung cancer

Background and purpose

Early detection of local recurrences following stereotactic ablative radiotherapy (SABR) for lung cancer may allow for curative salvage treatment, but recurrence can be difficult to distinguish from fibrosis. We studied the clinical performance of CT imaging high-risk features (HRFs) for detecting local recurrence.

Materials and methods

Patients treated with SABR for early stage lung cancer between 2003 and 2012 who developed pathology-proven local recurrence (n = 12) were matched 1:2 to patients without recurrences (n = 24), based on baseline factors. Serial CT images were assessed by blinded radiation oncologists. Previously reported HRFs were (1) enlarging opacity at primary site; (2) sequential enlarging opacity; (3) enlarging opacity after 12-months; (4) bulging margin; (5) loss of linear margin and (6) air bronchogram loss.

Results

All HRFs were significantly associated with local recurrence (p < 0.01), and one new HRF was identified: cranio-caudal growth (p < 0.001). The best individual predictor of local recurrence was opacity enlargement after 12-months (100% sensitivity, 83% specificity, p < 0.001). The odds of recurrence increased 4-fold for each additional HRF detected. The presence of ?3 HRFs was highly sensitive and specific for recurrence (both >90%).

Conclusion

The systematic assessment of post-SABR CT images for HRFs enables the accurate prediction of local recurrence.     

A methodology for dosimetry audit of rotational radiotherapy using a commercial detector array

Purpose

To develop a methodology for the use of a commercial detector array in dosimetry audits of rotational radiotherapy.

Materials and methods

The methodology was developed as part of the development of a national audit of rotational radiotherapy. Ten cancer centres were asked to create a rotational radiotherapy treatment plan for a three-dimensional treatment-planning-system (3DTPS) test and audited. Phantom measurements using a commercial 2D ionisation chamber (IC) array were compared with measurements using 0.125 cm³ IC, Gafchromic film and alanine pellets in the same plane. Relative and absolute gamma index (γ) comparisons were made for Gafchromic film and 2D-Array planes, respectively.

Results

Comparisons between individual detectors within the 2D-Array against the corresponding IC and alanine measurement showed a statistically significant concordance correlation coefficient (both ρ_c > 0.998, p < 0.001) with mean difference of −1.1 ± 1.1% and −0.8 ± 1.1%, respectively, in a high dose PTV. In the γ comparison between the 2D-Array and film it was that the 2D-Array was more likely to fail planes where there was a dose discrepancy due to the absolute analysis performed.

Conclusions

It has been found that using a commercial detector array for a dosimetry audit of rotational radiotherapy is suitable in place of standard systems of dosimetry.     

Dynamic contrast enhanced CT aiding gross tumor volume delineation of liver tumors: An interobserver variability study

Purpose

To evaluate the application of perfusion CT for gross tumor volume (GTV) delineation for radiotherapy of intrahepatic tumors.

Materials and methods

15 radiotherapy patients with confirmed liver tumors underwent contrast enhanced 4D-CT (Philips Brilliance Big-bore) as well as dynamic contrast enhanced (DCE) CT (GE 750HD). Perfusion maps were generated with CT perfusion v5 from GE. Five observers delineated GTVs of all intrahepatic foci on the 4D-CT, time-averaged DCE-CT and perfusion CT for every patient. STAPLE consensus contours were generated. Dice’s coefficients were compared between GTVs generated by observers on each image set and the corresponding consensus GTVs. Comparisons were also performed with patients stratified by hepatocellular carcinoma (HCC) metastatic tumors, and by tumor volume.

Results

Overall, mean Dice’s coefficients were 0.81 ± 0.14, 0.84 ± 0.10, and 0.81 ± 0.14 for 4D-CT, DCECT and perfusion. DCE-CT performed significantly better than 4D-CT and perfusion (p = 0.005 and p = 0.01 respectively). For patients with HCC, DCE-CT reduced interobserver variability significantly compared to 4D-CT (Dice’s coefficients 0.87 vs. 0.84, p < 0.05). For patients with metastatic disease time-averaged DCE-CT images decreased variability compared to 4D-CT (Dice’s coefficient 0.81 vs. 0.76, p < 0.05), especially true for tumors < 100 cc. The smaller tumors results are important to be included here.

Conclusions

DCE-CT imaging of liver perfusion reduced interobserver variability in GTV delineation for both HCC and metastatic liver tumors.     

Delineation of small mobile tumours with FDG-PET/CT in comparison to pathology in breast cancer patients

Purpose

Various segmentation methods for 18F-fluoro-2-deoxy-d-glucose (FDG) positron emission tomography/computed tomography (PET/CT) images were correlated with pathological volume in breast cancer patients as a model of small mobile tumours.

Methods

Thirty women with T2–T3/M0 breast invasive ductal carcinoma (IDC) were included prospectively. A FDG-PET/CT was acquired 4 ± 3 d before surgery in prone and supine positions, with/without respiratory gating. The segmentation methods were as follows: manual (Vm), relative (Vt%) and adaptive (Va) standard uptake value (SUV) threshold and semi-automatic on CT (Vct). Pathological volumes (Vpath) were measured for 26 lesions.

Results

The mean (±SD) Vpath was 4.1 ± 2.9 mL, and the lesion displacements were 3.9 ± 2.8 mm (median value: 3 mm). The delineated VOIs did not vary with the acquisition position nor with respiration, regardless of the segmentation method. The Vm, Va, Vct and Vt% methods, except Vt30%, were correlated with Vpath (0.5 < r < 0.8). The Vt50% and Vm were the most accurate methods (mean ± SD: 0.0 ± 1.6 mL and +0.6 ± 1.8 mL, respectively), followed by the Vct method.

Conclusions

When compared with pathology, small lesions (diameter <50 mm) with limited respiratory displacement (i.e., breast or apical lung lesions) are best delineated on FDG-PET/CT using a 50% SUVmax threshold. The acquisition position and respiratory gating did not modify the delineated volumes.     

Utility of FDG PET in patients with squamous cell carcinomas of the oral cavity

Background

The utility of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET) in oral cavity cancer has received little attention in a clinician's perspective. We systematically evaluated the clinical roles of FDG PET in patients with oral cavity squamous cell carcinomas (SCCs).

Methods

Between August 2001 and February 2005, 82 new patients with resectable oral cavity SCCs underwent CT/MRI and FDG PET at initial staging and follow-up. The sensitivity and specificity of CT/MRI and FDG PET for neck metastases were compared with histopathologic reference of 67 patients who underwent neck dissection. The relationships between the maximal standardized uptake value (SUV) of primary tumors and clinicopathologic parameters, such as gender, age, tumor thickness, local invasiveness, T and N categories, tumor-node-metastasis stage, and histological grade, as well as with disease-free survival (DFS), were assessed.

Results

FDG PET was more sensitive than CT/MRI for detecting cervical metastases on a level-by-level basis (38/43 vs. 28/43; P = 0.002). Age, T and N categories, tumor thickness (>8 mm) and SUV (>5.0) were also significant variables of 3-year DFS in univariate analysis. T category was an independent determinant of DFS in multivariate analysis (P < 0.05). During a mean follow-up of 36 months, FDG PET correctly diagnosed locoregional recurrences in 20 patients, distant metastases in six and second cancers in five.

Conclusion

FDG PET may have potential roles in initial staging, survival prediction, and the detection of recurrences and second cancers.     

Radiofrequency ablation after transarterial embolization as therapy for patients with unresectable hepatocellular carcinoma

Purpose

To evaluate the usefulness of transcatheter arterial embolization (TAE) followed by radiofrequency ablation (RFA) as combined treatment for unresectable hepatocellular carcinoma (HCC).

Patients and methods

Thirty-six consecutive patients (cirrhosis, Child-Pugh class A or B) with solitary or oligonodular HCC were treated (41 lesions; mean size, 58.9 mm; range, 30–120 mm). RFA was performed after one TAE treatment. Local efficacy was evaluated with multiphasic computed tomography (CT) performed an average of two months after RFA and once during later follow-up.

Results

The mean follow-up period was 16 months (range, 2–45 months). Technical success (namely, complete tumor devascularization during the arterial phase) was achieved for 59% of lesions at the first CT evaluation and for 46% at the second evaluation. Among prognostic factors included in the analysis, only lesion diameter (<50 mm versus ≥50 mm) was statistically significant in terms of predicting local success (Fisher's exact test: 85% versus 43% at first CT, p < 0.01; 70% versus 36% during follow-up, p = 0.05). There were no major periprocedural complications. Kaplan–Meier analysis showed survival rates of 84% at 12 months and 57% at 24 months.

Conclusions

Combined therapy – TAE then RFA – for unresectable HCC lesions in patients with cirrhosis produces a relatively high complete local response rate compared with TAE or RFA alone. Our results, considered with those from other case series, may help design prospective, randomized clinical trials to test combination therapy versus single-modality therapy in terms of risks and benefits.