Intraepithelial tumor-infiltrating lymphocytes shape loco-regional PET/CT spread of locally advanced cervical cancer.

BACKGROUND: Data suggest an association between positron emission tomography/CT (PET/CT) metabolic metrics and tumor microenvironment in several malignancies, and a potential role of PET/CT to monitor response to immunotherapy. OBJECTIVE: To evaluate the correlation between tumor loco-regional extension and tumor-infiltrating lymphocyte infiltration in locally advanced cervical cancer prior to concurrent chemo-radiotherapy.The secondary objective was to assess the association between tumor-infiltrating lymphocytes and PET/CT metabolic metrics. METHODS: Patients with locally advanced cervical cancer and negative para-aortic extensions on PET/CT were included. Two senior nuclear medicine physicians specializing in gynecologic oncology reviewed all PET/CT exams, and extracted tumor maximum standardized uptake value, metabolic tumor volume, and total lesion glycolysis, as well as pelvic lymph node involvement. One senior gynecologic oncology pathologist assessed intraepithelial tumor-infiltrating lymphocytes and stromal tumor-infiltrating lymphocytes. Intraepithelial tumor-infiltrating lymphocytes were categorized following previous studies as <1% and >1%. The cut-off for stromal tumor-infiltrating lymphocytes was chosen empirically: intermediate <60% and high >60%. RESULTS: 86 patients were included. Intraepithelial tumor-infiltrating lymphocytes were not significantly associated with tumor metabolic metrics. Intraepithelial tumor-infiltrating lymphocytes were not significantly associated with maximum standard uptake value (p=0.16), or metabolic tumor volume (p=0.19). Tumors with <1% intraepithelial tumor-infiltrating lymphocytes score were associated with a higher MRI tumor size (≥ median) (63.3% vs 39.3%, p=0.04). Patients with pelvic lymph node uptake were significantly more frequent in patients with high stromal tumor-infiltrating lymphocytes score (≥60%) (61.5% vs 31.7%, p=0.009). CONCLUSIONS: Poor or absent intraepithelial tumor-infiltrating lymphocytes were associated with more advanced disease at diagnosis and larger tumor size. Tumor-infiltrating lymphocytes were not associated with tumor metabolic activity. Intraepithelial and stroma tumor-infiltrating lymphocytes are not redundant and should be assessed separately. Further work is needed to evaluate the association between tumor metabolic profile and immune populations, including different T-cell subtypes for patient selection for immunotherapy strategies.

PET-MRI for evaluation of response to radiochemotherapy in patients with locally advanced cervical cancer.

OBJECTIVE: We aimed to analyze the diagnostic test accuracy of positron emission tomography and a magnetic resonance imaging scan (PET-MRI) fusion in evaluating tumor response after radiochemotherapy in patients with locally advanced cervical cancer. METHODS: Patients treated at two institutes between January 2008 and December 2016 were studied retrospectively. Re-evaluation by positron emission tomography (PET) and magnetic resonance imaging (MRI) was performed in a non-concurrent way 4-8 weeks after treatment. A nuclear medicine doctor and a radiologist (subsequently referred as "radiologists"), both experts in gynecological oncology, re-examined the post-treatment MRI and positron emission tomography-computed tomography (PET-CT) separately, and then performed a fusion of these examinations. In this study we describe this "a posteriori fusion methodology", with two levels, enabling limitation of anatomical shifts. The gold standard was anatomical pathology analysis of the surgical specimen, since all patients underwent surgery following this radiological re-evaluation. The radiologists' degree of certainty in their diagnoses, and the impact of fusion on their diagnostic confidence were assessed by the radiologists, using two Likert judgment scales. They also adjudicated on possible changes of interpretation after the fusion. RESULTS: Thirty-one patients were included. The PET-MRI fusion has a sensitivity of 79% and a specificity of 90%. The positive predictive value (PPV) was 94%, and the negative predictive value (NPV) was 69%. In 45% of cases (n=13), radiologists reported an improvement in their degree of certainty in their diagnosis using a Likert judgment scale, due to inspecting the PET and MRI fused. A change in interpretation of tumor response was observed using a Likert judgment scale in 31% of cases. CONCLUSION: PET-MRI fusion improves the radiologist's own diagnostic confidence in assessing response to concurrent radiochemotherapy in locally advanced cervical cancer. More studies using a latest generation hybrid system will be necessary to further compare to MRI and PET-CT.

Metabolic activity determines survival depending on the level of lymph node involvement in cervical cancer.

BACKGROUND: To assess the impact of PET/CT functional parameters on survival, locoregional, and distant failure according to the most distant level of lymph node [18F]FDG uptake in patients with locally advanced cervical cancer (LACC). METHODS: Retrospective study including 148 patients with LACC treated with concurrent chemoradiotherapy after PET/CT and para-aortic lymph node (PALN) surgical staging. Two senior nuclear medicine physicians reviewed all PET/CT exams and retrieved tumor and lymph node metabolic parameters: SUVmax, MTV, TLG. Oncological outcomes according to metabolic parameters and level of lymph node spread on PET/CT were assessed. RESULTS: In patients without lymph node uptake on PET/CT, high MTV values of the cervical tumor were associated with DFS (HR = 5.14 95%CI = [2.15-12.31]), OS (HR = 6.10 95%CI = [1.89-19.70]), and time to distant (HR = 4.73 95%CI = [1.55-14.44]) and locoregional recurrence (HR = 5.18 95%CI = [1.72-15.60]). In patients with pelvic lymph node (PLN) uptake but without PALN uptake on [18F]FDG-PET/CT, high MTV values of the cervical tumor were associated with DFS (HR = 3.17 95%CI = [1.02-9.83]) and OS (HR = 3.46 95%CI = [0.96-12.50]), and the number of PLN fixations was associated with DFS (HR = 1.30 95%CI = [1.10-1.53]), OS (HR = 1.35 95%CI = [1.11-1.64]), and time to distant (HR = 1.35 95%CI = [1.08-1.67]) and locoregional recurrence (HR = 1.31 95%CI = [1.08-1.59]). There was no significant association between cervical tumor metabolic or lymph node metrics and survival outcome in patients with PALN uptake. CONCLUSIONS: Cervical MTV is more accurate than SUVmax to predict survival outcome in patients with locoregional disease confined to the pelvis and should be implemented in routine clinical practice. Prognostic value of metabolic metrics disappears with PALN uptake, which is associated with distant failure in nearly half of patients.

Extended pelvic resection for gynecological malignancies: A review of out-of-the-box surgery.

The term 'out-of-the-box surgery' in gynecologic oncology was recently coined to describe the resection of tumor growing out of the endopelvic cavity. In the specific case of pelvic sidewall involvement, a laterally extended pelvic resection may be required. As previously defined by Höckel, this resection requires the en bloc removal of structures including the pelvic sidewall muscles, bones, nerves, and/or major vessels. This complex radical procedure leads to tumor-free margins in more than 75% of the patients, with reliable functional results. The rate of recurrence and overall survival are directly correlated with clear resection margins. Progress in imaging, surgical techniques, and perioperative care currently offer the opportunity to attempt surgical curative resection in selected patients for whom palliative therapy was the only alternative. However, the procedure is associated with a high rate of major postoperative complications affecting up to 60% of patients. Multidisciplinary expert centers are the most likely to achieve this complex surgery with favorable oncological outcomes. The aim of this review is to summarize the key issues of out-of-the-box surgery in gynecologic cancer.

Performance of Multiparametric Functional Imaging to Assess Peritoneal Tumor Burden in Ovarian Cancer.

PURPOSE: The aim of the study was to evaluate the clinical utility of pretreatment 18F-FDG PET/CT with quantitative evaluation of peritoneal metabolic cartography in relation to staging laparoscopy for ovarian carcinomatosis. PATIENTS AND METHODS: A retrospective review of prospectively collected data from 84 patients with FIGO (International Federation of Gynecology and Obstetrics) stage IIIC to IV ovarian cancer was carried out. All patients had a double-blinded 18F-FDG PET/CT review. Discriminant capacity of metabolic parameters to identify peritoneal carcinomatosis in the 13 abdominal regions according to the peritoneal cancer index was estimated with area under the receiver operating characteristic curve (AUC). RESULTS: The metabolic parameter showing the best trade-off between sensitivity and specificity to predict peritoneal extension compared with peritoneal cancer index score was the metabolic tumor volume (MTV), with a Spearman ρ equal to 0.380 (P < 0.001). The AUC of MTV to diagnose peritoneal involvement in the upper abdomen (regions 1, 2, and 3) ranged from 0.740 to 0.765. MTV AUC values were lower in the small bowel regions (9-12), ranging from 0.591 to 0.681, and decreased to 0.487 in the pelvic region 6. 18F-FDG PET/CT also improved the detection of extra-abdominal disease, upstaging 35 patients (41.6%) from stage IIIC to IV compared with CT alone and leading to treatment modification in more than one third of patients. CONCLUSIONS: 18F-FDG PET/CT metrics are highly accurate to reflect peritoneal tumor burden, with variable diagnostic value depending on the anatomic region. MTV is the most representative metabolic parameter to assess peritoneal tumor extension.

Lateral Hepatic Fissure Peritoneal Carcinomatosis as a Pitfall for Hepatic Metastasis of Advanced Ovarian Cancer.

ABSTRACT: A 52-year-old woman previously treated for a stage IIIc high-grade ovarian serous carcinoma presented right upper quadrant abdominal pain, 3 years after extended surgery and chemotherapy. Abdominal CT, MRI, and 18F-FDG PET/CT showed a right hepatic mass, consistent for lone recurrence nearby the hepatic lateral fissure. Preoperative and histologic examination identified a peritoneal lateral fissure lesion. The patient underwent atypic segment 5 segmentectomy. She has been disease-free for 3 years now. Advanced ovarian cancer can be responsible for perihepatic sulcus lesions, such as this right fissure lesion. They should not be mistaken for inoperable parenchyma metastases.

Concordance between preoperative ESMO-ESGO-ESTRO risk classification and final histology in early-stage endometrial cancer.

OBJECTIVE: To evaluate the concordance between preoperative European Society for Medical Oncology (ESMO)-European Society of Gynaecological Oncology (ESGO)-European SocieTy for Radiotherapy and Oncology (ESTRO) risk classification in early-stage endometrial cancer (EC) assessed by biopsy and magnetic resonance imaging (MRI) with this classification based on histology of surgical specimen. METHODS: This bicentric retrospective study included women diagnosed with early-stage EC (≤stage II) who had a complete preoperative assessment and underwent a surgical management from January 2011 to December 2018. Patients were preoperatively classified into 3 degrees of risk of lymph node (LN) involvement based on biopsy and MRI. Based on final histological report, patients were re-classified using the preoperative classification. Concordance between the preoperative assessment and definitive histology was calculated with weighted Cohen's kappa coefficient. RESULTS: A total of 333 women were included and kappa coefficient of preoperative risk classification was 0.49. The risk was underestimated and overestimated in 37% and 10% of cases, respectively. Twenty-nine percent of patients had an incomplete LN staging according to the degree of risk of re-classification. The observed discordance in the risk classification was attributed to MRI in 75% of cases, to biopsy in 18% and in 7% to both (p<0.001). Kappa coefficient for concordance was 0.25 for MRI and 0.73 for biopsy. CONCLUSION: Concordance between preoperative ESMO-ESGO-ESTRO risk classification and final histology is weak. Given that the risk was underestimated in the majority of patients wrongly classified, sentinel LN procedure instead of no LN dissection could be an option offered to preoperative low-risk patients to decrease the indication of second surgery for re-staging and/or to avoid toxicity of adjuvant radiotherapy.

Postoperative chest liver herniation after cardiophrenic lymph node resection by a transdiaphragmatic approach following primary cytoreductive surgery for advanced endometrioid ovarian cancer: A case report.

Resection of enlarged cardiophrenic lymph nodes (CPLN) is a procedure required to obtain complete cytoreduction in selected patients affected by advanced ovarian cancer. Their resection by transdiaphragmatic approach has been demonstrated to be feasible with low rates of morbidity. The main complications associated with this procedure are pleural effusion, pneumothorax, and rarely, chylothorax. This case describes a postoperative chylothorax and chest liver herniation in a patient who underwent a cytoreductive surgery for advanced endometrioid ovarian cancer, which included a right transdiaphragmatic CPLN resection. Surgical management by thoracotomy was required to repair the right diaphragmatic defect combined with conservative management of the chylothorax. The diaphragmatic closure was achieved employing interrupted stitches with a non-absorbable suture. No prosthetic material was required.

Comparison of SPECT-CT with intraoperative mapping in cervical and uterine malignancies.

INTRODUCTION: The objective was to evaluate whether hybrid imaging combining single photon emission tomography with computed tomography (SPECT/CT) provides additional clinical value for dectection of sentinel lymph nodes (SLNs) compared with intraoperative combined mapping in uterine and cervical malignancies. METHODS: This was a retrospective study of prospectively collected data from patients with stages IA-IB2 cervical cancer (International Federation of Gynecology and Obstetrics (FIGO) 2018) or stage I endometrial cancer, who underwent preoperative SPECT/CT for SLN detection. All included patients had dual injection of technetium-99m (99mTc) with patent blue or indocyanine green. RESULTS: A total of 171 patients were included with 468 SLNs detected during surgery: 146/171 patients (85.4%) had both radiotracer and blue injection whereas 25/171 patients (14.6%) had radiotracer and indocyanine green injected. The overall detection rate was 95.3%. The detection rate of SLN mapping was 74.9% for SPECT/CT, 90.6% for 99mTc, 91.8% for blue dye, and 100% for indocyanine green. Bilateral drainage was found in 140 patients (81.9%), detected by 99mTc in 105 patients (61.4%), by blue in 99 patients (67.3%), by indocyanine green in 23 patients (92%), and by SPECT/CT in 62 patients (36.4%). Atypical SLN locations were identified by SPECT/CT in 64 patients (37.4%), by 99mTc in 28 patients (16.4%), by blue in 17 patients (9.9%), and by indocyanine green in 8 patients (4.7%). Sensitivity and negative predictive value of SLN biopsy to detect lymph node metastasis using dual injection of different intraoperative combined techniques were 88.9% and 97.5%, respectively. CONCLUSION: SPECT/CT enhanced topographic delineation of SLN and more accurately identified drainage to atypical locations. Fluorescent SLN mapping using indocyanine green offered the highest SLN detection rate. When indocyanine green was used, SPECT/CT did not increase SLN detection, and did not add further information to improve lymph node localization and removal.

Concordance of laparoscopic and laparotomic peritoneal cancer index using a two-step surgical protocol to select patients for cytoreductive surgery in advanced ovarian cancer.

PURPOSE: The aim of our study was to assess concordance of staging laparoscopy and cytoreductive surgery (CRS) peritoneal cancer index (PCI) when applying a two-step surgical protocol. We also aimed to evaluate the accuracy of diagnostic laparoscopy to triage patients for complete cytoreduction, and to define optimal time between staging laparoscopy and CRS. METHODS: We designed a retrospective review of prospectively collected data from patients with advanced ovarian cancer who underwent a diagnostic laparoscopy followed by a CRS a few weeks later (two-step surgical protocol), from January 2010 to April 2019. Only patients selected for complete cytoreduction, and with available PCI score from both surgeries were included. PCI concordance was assessed using intraclass correlation coefficient (ICC). RESULTS: During the study period 543 patients underwent a laparoscopic staging for ovarian carcinomatosis. Among them, 43 patients fulfilled inclusion criteria. ICC between laparoscopic and laparotomic PCI was 0.54. After applying the linear regression equation: laparoscopic PCI + 0.2 x [days between surgeries] + 2, ICC increased to 0.79. Completeness cytoreduction score and laparoscopic PCI were significantly associated (OR 1.27, 95% CI 1.03-1.57, p = 0.03). AUC of laparoscopic PCI to predict complete cytoreduction was 0.90. CONCLUSION: Concordance between laparoscopic PCI assessment and PCI score at the end of CRS is fair within a two-step surgical management. Laparoscopic assessment underestimates final PCI score by two points, and this difference increases with the delay between both surgeries. Diagnostic laparoscopy can adequately select patients for CRS, and optimal time to perform it is no more than 10 days after laparoscopy.

Primary B-Cell lymphoma of the uterine cervix presenting with right ureter hydronephrosis: A case report.

Primary lymphoma of the uterine cervix is a very infrequent disease, usually affecting perimenopausal women. Symptoms are very similar to other gynecological malignancies, but treatment and prognosis completely differ, as most of these patients have a better survival. This condition has to be suspected in women with recent normal Pap smear test, rapidly growing tumor and initially non-contributory biopsies. We report a case of primary diffuse large-B-cell lymphoma of the uterine cervix mimicking a locally advanced cervical cancer with right ureter hydronephrosis at diagnosis. She was medically managed with a combination of rituximab and chemotherapy with cyclophosphamide, hydroxydaunorubicin, oncovin, and prednisone, associated to methotrexate for central nervous system prophylaxis. We will discuss about the role of combined treatments with surgery and radiotherapy, and the fertility sparing management in young women.

18F-FDG PET/CT Identifies Predictors of Survival in Patients with Locally Advanced Cervical Carcinoma and Paraaortic Lymph Node Involvement to Allow Intensification of Treatment.

Our objective was to use 18F-FDG PET/CT to identify a high-risk subgroup requiring therapeutic intensification among patients with locally advanced cervical cancer (LACC) and paraaortic lymph node (PALN) involvement. Methods: In this retrospective multicentric study, patients with LACC and PALN involvement concurrently treated with chemoradiotherapy and extended-field radiotherapy between 2006 and 2016 were included. A senior nuclear medicine specialist in PET for gynecologic oncology reviewed all 18F-FDG PET/CT scans. Metabolic parameters including SUVmax, metabolic tumor volume, and total lesion glycolysis (TLG) were determined for the primary tumor, pelvic lymph nodes, and PALNs. Associations between these parameters and overall survival (OS) were assessed with the Cox proportional hazards model. Results: Sixty-eight patients were enrolled in the study. Three-year OS was 55.5% (95% confidence interval, 40.8-68.0). When adjusted for age, stage, and histology, pelvic lymph node TLG, PALN TLG, and PALN SUVmax were significantly associated with OS (P < 0.005). Conclusion:18F-FDG PET/CT was able to identify predictors of survival in the homogeneous subgroup of patients with LACC and PALN involvement, thus allowing therapeutic intensification to be proposed.

Chemoradiotherapy for locally advanced cervix cancer without aortic lymph node involvement: can we consider metabolic parameters of pretherapeutic FDG-PET/CT for treatment tailoring?

PURPOSE: Aim of the study was to assess impact of pretherapeutic FDG-PET/CT metabolic parameters on response to chemoradiotherapy (CRT) and survival in locally advanced cervical cancer (LACC) patients without paraaortic lymph node involvement. METHODS: LACC patients treated with CRT without macrometastatic involvement after paraaortic surgical staging were included. All patients had received at least 45 Gy radiotherapy and five cycles of platinum-based chemotherapy. High-risk histologies were excluded. Two senior nuclear physician experts in gynaecologic oncology reviewed all PET/CT exams, and extracted tumor SUVmax, MTV, and TLG (standardized uptake value, metabolic tumor volume, and total lesion glycolysis respectively). Response to CRT was assessed with a pelvic MRI done after 45 Gy. Medical charts were reviewed for clinical, pathology, and survival data. RESULTS: Ninety-three patients were included in the study. The overall survival (OS) rates at 2 and 5 years were 83.0% [95%CI: 72.5-89.8] and 71.2% [57.5-81.2] respectively. The RFS rates at 2 and 5 years were 72.5% [61.5-80.9] and 64.4% [52.3-74.2] respectively. Higher cervical SUVmax and TLG were significantly associated with poor response to CRT. In multivariate analysis, cervical SUVmax was the main predictive factor for OS. CONCLUSION: Cervical tumor SUVmax was demonstrated to be a non-invasive prognostic biomarker for response to treatment and survival in LACC patients without paraaortic involvement. SUVmax and other PET/CT metabolic parameters require further prospective investigation to help tailoring of local treatment.

Incidental Finding of Intrathyroid Metastases of Prostatic Cancer on 18F-Choline PET/CT.

An 85-year-old man with a 2-year history of prostate cancer, treated with radiotherapy and hormonal therapy, presented increased prostatic-specific antigen levels. F-choline PET/CT showed focal prostatic uptake consistent with known local recurrence, increased uptake of 2 hypodense thyroid nodules and of 2 left cervical lymph nodes, suspected as thyroid cancer. Neck ultrasound confirmed the high risk of malignancy, and a guided biopsy (of a thyroid nodule and cervical lymph node) revealed cellular infiltrates thyroid transcription factor-1 (TTF-1) negative and prostatic-specific antigen positive, confirming intrathyroid and cervical lymph node metastases of prostate cancer. PET/CT changed the disease staging. Chemotherapy was initiated.

Diagnosis of an intestinal mucormycosis 'fungus ball' located with PET/CT with [18F] FDG-PET/CT.

Mucormycosis is a life-threatening infection with most commonly rhino-orbital-cerebral and pulmonary syndromes that mostly occurs in immunocompromised patients. FDG-PET/CT emerged as a sensitive non-invasive tool to identify systemic mucormycosis. We present a 59-year-old woman for whom a PET/CT with 18F-FDG was performed in search of a primary location of mucormycosis with non-contributive conventional workup. A large left abdominal mass was seen, compatible with a fungus ball, with intense parietal uptake and without any central uptake. The localization of the infection provided a target for surgery and permitted to adapt the therapeutic strategy. After resection, the final diagnosis was consistent with mucormycosis. To our knowledge, this is the first report of a PET/CT image with FDG showing an intestinal fungus ball. PET/CT with 18F-FDG may contribute to the management of patients with fungal infections of unknown origin.

Fluorine-18-fluorocholine PET/CT parameters predictive for hematological toxicity to radium-223 therapy in castrate-resistant prostate cancer patients with bone metastases: a pilot study.

PURPOSE: This study aims to predict hematological toxicity induced by Ra therapy. We investigated the value of metabolically active bone tumor volume (MBTV) and total bone lesion activity (TLA) calculated on pretreatment fluorine-18-fluorocholine (F-FCH) PET/CT in castrate-resistant prostate cancer (CRPC) patients with bone metastases treated with Ra radionuclide therapy. PATIENTS AND METHODS: F-FCH PET/CT imaging was performed in 15 patients with CRPC before treatment with Ra. Bone metastatic disease was quantified on the basis of the maximum standardized uptake value (SUV), total lesion activity (TLA=MBTV×SUVmean), or MBTV/height (MBTV/H) and TLA/H. F-FCH PET/CT bone tumor burden and activity were analyzed to identify which parameters could predict hematological toxicity [on hemoglobin (Hb), platelets (PLTs), and lymphocytes] while on Ra therapy. Pearson's correlation was used to identify the correlations between age, prostate-specific antigen, and F-FCH PET parameters. RESULTS: MBTV ranged from 75 to 1259 cm (median: 392 cm). TLA ranged from 342 to 7198 cm (median: 1853 cm). Patients benefited from two to six cycles of Ra (n=56 cycles in total). At the end of Ra therapy, five of the 15 (33%) patients presented grade 2/3 toxicity on Hb and lymphocytes, whereas three of the 15 (20%) patients presented grade 2/3 PLT toxicity.Age was correlated negatively with both MBTV (r=-0.612, P=0.015) and TLA (r=-0.596, P=0.018). TLA, TLA/H, and MBTV/H predicted hematological toxicity on Hb, whereas TLA/H and MBTV/H predicted toxicity on PLTs at the end of Ra cycles. Receiver operating characteristic curve analysis allowed to define the cutoffs for MBTV (915 cm) and TLA (4198 cm) predictive for PLT toxicity, with an accuracy of 0.92 and 0.99. CONCLUSION: Tumor bone burden calculation is feasible with F-FCH PET/CT with freely available open-source software. In this pilot study, baseline F-FCH PET/CT markers (TLA, MBTV) have shown abilities to predict Hb and PLT toxicity after Ra therapy and could be explored for patient selection and treatment optimization.

A clinical evaluation of the impact of the Bayesian penalized likelihood reconstruction algorithm on PET FDG metrics.

PURPOSE: The aim of this study was to evaluate the impact of using the Bayesian penalized likelihood (BPL) algorithm on a bismuth germanium oxide positron emission tomography (PET)/computed tomography (CT) system for F-FDG PET/CT exams in case of low injected activity and scan duration. MATERIALS AND METHODS: F-FDG respiratory gated PET/CT performed on 102 cancer patients, injected with ∼2 MBq/kg of F-FDG, were reconstructed using two algorithms: ordered subset expectation maximization (OSEM) and BPL. The signal-to-noise ratio (SNR) was calculated as the ratio of mean standard uptake value (SUV) over the standard deviation in a reference volume defined automatically in the liver. The peak SUV and volumes were also measured in lesions larger than 2 cm thanks to the automated segmentation method. RESULTS: On 85 respiratory gated patients, the median SNR was significantly higher with BPL (P<0.0001) and it is even better when the BMI of the patient increases (odds ratio=1.26).For the 55 lesions, BPL significantly increased the SUVpeak [difference: (-0.5; 1.4), median=0.4, P<0.0001] compared with OSEM in 83.6% of the cases. With BPL, the volume was lower in 61.8% of the cases compared with OSEM, but this was not statistically significant. CONCLUSION: The BPL algorithm improves the image quality and lesion contrast and appears to be particularly appropriate for patients with a high BMI as it improves the SNR. However, it will be important for patient follow-up or multicenter studies to use the same algorithm and preferably BPL.