Standardized uptake value by positron emission tomography/computed tomography as a prognostic variable in metastatic breast cancer

BACKGROUND:

In this retrospective, single‐institution study, the authors examine the maximum standardized uptake value (SUVmax) on positron emission tomography/computed tomography (PET/CT) images as a prognostic variable in patients with newly diagnosed metastatic breast cancer (MBC).

METHODS:

Patients with ≥1 metastatic lesion on PET/CT images that were obtained within 60 days of their MBC diagnosis between January 1, 2001 and December 31, 2008 were included. Patients were excluded if they had received chemotherapy ≤30 days before the PET/CT images were obtained. Electronic medical reports were reviewed to determine the SUVmax and overall survival. Because of intraindividual variation in the SUV by body site, separate analyses were conducted by metastatic site. Relationships between site‐specific PET/CT variable tertiles and overall survival were assessed using Cox regression; hazard ratios for the highest tertile versus the lowest tertile were reported.

RESULTS:

In total, 253 patients were identified, and their median age was 57 years (range, 27‐90 years). Of these, 152 patients (60%) died, and the median follow‐up was 40 months. On univariate analysis, SUVmax tertile was strongly associated with overall survival in patients who had bone metastases (N = 141; hazard ratio, 3.13; 95% confidence interval, 1.79‐5.48; P < .001). This effect was maintained on multivariate analysis (HR = 3.19; 95% confidence interval, 1.64‐6.20, P = .002) after correcting for known prognostic variables. A greater risk of death was associated with SUVmax tertile in patients who had metastases to the liver (N = 46; hazard ratio, 2.07; 95% confidence interval, 0.90‐4.76), lymph nodes (N = 149; hazard ratio, 1.1; 95% confidence interval, 0.69‐1.88), and lung (N = 62; hazard ratio, 2.2; 95% confidence interval, 0.97‐4.95), although these results were not significant (P = .18, P = .31, and P = .095, respectively).

CONCLUSIONS:

The current results indicate that PET/CT has value as a prognostic tool in patients with newly diagnosed MBC to bone. Cancer 2012. © 2012 American Cancer Society.     

Impact of positron emission tomography/computed tomography surveillance at 12 and 24 months for detecting head and neck cancer recurrence

BACKGROUND:

In head and neck cancer (HNC), 3‐month post‐treatment positron emission tomography (PET)/computed tomography (CT) reliably identifies persistent/recurrent disease. However, further PET/CT surveillance has unclear benefit. The impact of post‐treatment PET/CT surveillance on outcomes is assessed at 12 and 24 months.

METHODS:

A 10‐year retrospective analysis of HNC patients was carried out with long‐term serial imaging. Imaging at 3 months included either PET/CT or magnetic resonance imaging, with all subsequent imaging comprised of PET/CT. PET/CT scans at 12 and 24 months were evaluated only if preceding interval scans were negative. Of 1114 identified patients, 284 had 3‐month scans, 175 had 3‐ and 12‐month scans, and 77 had 3‐, 12‐, and 24‐month scans.

RESULTS:

PET/CT detection rates in clinically occult patients were 9% (15 of 175) at 12 months, and 4% (3 of 77) at 24 months. No difference in outcomes was identified between PET/CT‐detected and clinically detected recurrences, with similar 3‐year disease‐free survival (41% vs 46%, P = .91) and 3‐year overall survival (60% vs 54%, P = .70) rates. Compared with 3‐month PET/CT, 12‐month PET/CT demonstrated fewer equivocal reads (26% vs 10%, P < .001). Of scans deemed equivocal, 6% (5 of 89) were ultimately found to be positive.

CONCLUSIONS:

HNC patients with negative 3‐month imaging appear to derive limited benefit from subsequent PET/CT surveillance. No survival differences were observed between PET/CT‐detected and clinically detected recurrences, although larger prospective studies are needed for further investigation. Cancer 2013. © 2012 American Cancer Society.     

Ability of integrated positron emission and computed tomography to detect significant colonic pathology

BACKGROUND:

The ability of integrated positron emission tomography and computed axial tomography (PET‐CT) to detect colonic pathology is not fully defined. The purpose of this study was to assess the ability of PET‐CT to detect colonic pathology and to determine the significance of (¹⁸F)2‐fluoro‐2‐deoxyglucose (¹⁸F‐FDG) activity noted incidentally in the colon on PET‐CT.

METHODS:

Records for all patients who underwent PET‐CT and colonoscopy at our institution were reviewed. Patients with history of colonic malignancy or colon surgery were excluded.

RESULTS:

Fifty‐eight patients had incidental colonic ¹⁸F‐FDG activity on PET (Group A) and 272 had none (Group B). In Group A, 65% of patients had pathologic findings detected on colonoscopy that corresponded to the site of PET activity. Standardized uptake value (SUV) readings were not helpful in distinguishing true‐positives from false‐positives. In Group B, 11.8% of patients were found to have significant colonic findings. Lesions not detected by PET‐CT included 4 colon cancers, 7 advanced adenomas, and 10 patients with colonic lymphoma. Overall, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of PET‐CT for detecting significant pathology were 53%, 93%, 65%, 89%, and 85%, respectively. For detecting colon cancer and adenomas 10 mm or more, the sensitivity, specificity, PPV, NPV, and accuracy of PET‐CT were 72%, 90%, 45%, 96%, and 88%, respectively.

CONCLUSIONS:

Incidental colonic activity detected by PET‐CT warrants further evaluation with colonoscopy. However, negative PET‐CT does not rule out significant colonic pathology including colon cancer, advanced adenomas, or lymphoma. Cancer 2010. © 2010 American Cancer Society.     

The diagnostic and prognostic utility of positron emission tomography/computed tomography‐based follow‐up after radiotherapy for head and neck cancer

BACKGROUND:

The detection of subclinical head and neck cancer recurrence or a second primary tumor may improve survival. In the current study, the authors investigated the clinical value of a follow‐up program incorporating serial ¹⁸F?fluorodeoxyglucose?positron emission tomography integrated with computed tomography (PET/CT) in the detection of recurrent disease in patients with head and neck cancer.

METHODS:

A total of 240 PET/CT scans were reviewed in 80 patients with head and neck cancer who were treated with radiotherapy (RT) from July, 2005 through August, 2007. All patients were followed with clinical examination, PET/CT, and correlative imaging for a minimum of 11 months (median follow?up, 21 months).

RESULTS:

The sensitivity, specificity, and positive and negative predictive values of PET/CT‐based follow‐up for detecting locoregional recurrence were 92%, 82%, 42%, and 98%, respectively. Corresponding values for distant metastases or second primary tumors were 93%, 96%, 81%, and 98%, respectively. Eight patients (10%) developed disease recurrences or second primary tumors that were amenable to salvage surgery with negative surgical margins. The 2‐year progression‐free survival and 2‐year overall survival rates were significantly different between patients who had a negative and those with a positive PET/CT result within 6 months of the completion of RT (93% vs 30% [P<.001] and 100% vs 32% [P<.001], respectively).

CONCLUSIONS:

Although post‐therapy follow‐up using PET/CT is reportedly associated with a high false‐positive rate in the irradiated head and neck, PET/CT appears to be a highly sensitive technique for the detection of recurrent disease. Furthermore, negative PET/CT results within 6 months of the completion of RT offer significant prognostic value. Cancer 2009. © 2009 American Cancer Society.     

High rates of tumor growth and disease progression detected on serial pretreatment fluorodeoxyglucose‐positron emission tomography/computed tomography scans in radical radiotherapy candidates with nonsmall cell lung cancer

BACKGROUND:

The authors studied growth and progression of untreated nonsmall cell lung cancer (NSCLC) by comparing diagnostic and radiotherapy (RT) planning fluorodeoxyglucose (FDG)‐positron emission tomography (PET)/computed tomography (CT) scans before proposed radical chemo‐RT.

METHODS:

Patients enrolled on a prospective clinical trial were eligible for this analysis if they underwent 2 pretreatment whole body FDG‐PET/CT scans, >7 days apart. Scan 1 was performed for diagnosis/disease staging and scan 2 for RT planning. Interscan comparisons included disease stage, metabolic characteristics, tumor doubling times, and change in treatment intent.

RESULTS:

Eighty‐two patients underwent planning PET/CT scans between October 2004 and February 2007. Of these, 28 patients (61% stage III, 18% stage II) had undergone prior staging PET/CT scans. The median interscan period was 24 days (range, 8‐176 days). Interscan disease progression (TNM stage) was detected in 11 (39%) patients. The probability of upstaging within 24 days was calculated to be 32% (95% confidence interval [CI], 18%‐49%). Treatment intent changed from curative to palliative in 8 (29%) cases, in 7 because of PET. For 17 patients who underwent serial PET/CT scans under standardized conditions, there was a mean relative interscan increase of 19% in tumor maximum standardized uptake value (SUV) (P = .022), 16% in average SUV (P = .004), and 116% in percentage injected dose (P = .002). Estimated doubling time of FDG avid tumor was 66 days (95% CI, 51‐95 days).

CONCLUSIONS:

Rapid tumor progression was detected in patients with untreated, predominantly stage III, NSCLC on serial FDG‐PET/CT imaging, highlighting the need for prompt diagnosis, staging, and initiation of therapy in patients who are candidates for potentially curative therapy. Cancer 2010. © 2010 American Cancer Society.     

The association between extent of lymphadenectomy and survival among patients with lymph node metastases undergoing radical cystectomy

BACKGROUND.

Long‐term survival in patients with lymph node‐positive bladder cancer who undergo cystectomy suggests a therapeutic role for lymphadenectomy. The objective of this study was to describe the association between extent of lymphadenectomy and survival in lymph node‐positive patients who underwent radical cystectomy.

METHODS.

The cohort consisted of patients from the Surveillance, Epidemiology, and End Results registry with transitional cell carcinoma who underwent cystectomy with lymphadenectomy and had at least 1 positive lymph node and no distant metastases. The Kaplan‐Meier method and multivariate Cox proportional‐hazards regression analyses were used to estimate differences in survival among different lymphadenectomy variables.

RESULTS.

In total, 1260 patients had at least 1 positive lymph node. A median of 9 lymph nodes were removed (range, 1–48 lymph nodes) with a median of 2 positive lymph nodes (range, 1–18 positive lymph nodes), and the median lymph node density was 22%. In multivariate analysis controlling for patient demographics, tumor classification, and year of diagnosis, the number of positive and total lymph nodes removed remained independent predictors of survival. There was an inverse association between the number of lymph nodes removed and the risk of death for all quartiles. Removal of > 10 lymph nodes was associated with increased overall survival (hazard ratio, 0.52; 95% confidence interval, 0.43–0.64). In addition, with a lymph node density from 0.1% to 12.5% as the referent group, each higher quartile experienced worse survival.

CONCLUSIONS.

An increased number of lymph nodes removed at the time of cystectomy was associated with improved survival in patients with lymph node‐positive bladder cancer. Improved survival was observed at a lower lymph node density threshold than previously reported. The current findings support performing a more extensive lymphadenectomy at the time of cystectomy. Cancer 2008. © 2008 American Cancer Society.     

Therapeutic role of lymphadenectomy for cervical cancer

BACKGROUND.

Despite the diagnostic value of lymphadenectomy for early‐stage cervical cancer, its therapeutic role is unknown. We examined the therapeutic potential of extensive lymphadenectomy in women with early‐stage cervical cancer.

METHODS.

Women with stage IA2‐IIA cervical cancer who underwent radical hysterectomy with lymphadenectomy in the Surveillance, Epidemiology, and End Results (SEER) database were analyzed. Patients were stratified according to the number of nodes removed. The effect of the extent of lymphadenectomy on overall and cancer‐specific survival was examined using multivariable Cox proportional hazards models. Separate analyses were performed for node positive and node negative patients.

RESULTS.

Among 5522 women, 893 (16%) had <10 nodes, 2030 (37%) had 11‐20, 1487 (27%) had 21‐30 nodes, and 1112 (20%) had >30 nodes removed. Black women, those >65 years of age and those diagnosed later in the study, were less likely to have 10 or more nodes removed (P < .05 for all). Among women with positive lymph nodes, a more extensive lymphadenectomy had no effect on survival (HR = 0.75; 95% CI, 0.47‐1.22). For women with negative lymph nodes, a more extensive lymphadenectomy was associated with improved survival. Compared with node negative patients with less than 10 nodes removed, patients with 21‐30 nodes removed were 24% (HR = 0.76; 95% CI, 0.53‐1.09) less likely to die, whereas those with >30 nodes removed were 37% (HR = 0.64; 95% CI, 0.43‐0.96) less likely to die from their tumors.

CONCLUSIONS.

Node negative, early‐stage cervical cancer patients who undergo a more extensive lymphadenectomy have an improved survival. Cancer 2011. © 2010 American Cancer Society.     

The clinical application of 18F‐fluorodeoxyglucose positron emission tomography to predict survival in patients with operable esophageal cancer

BACKGROUND:

Metabolic tumor activity using ¹⁸F‐fluorodeoxyglucose positron emission tomography (FDG‐PET) was believed to have a predictive value for patient outcome in malignancies. The objective of the current study was to assess the prognostic effectiveness of the highest standardized uptake value (SUV) in the primary or regional area (peak SUV) and the number of PET‐positive lymph nodes in esophageal cancer.

METHODS:

The authors retrospectively reviewed their experience with 184 consecutive esophageal cancer patients imaged preoperatively using FDG‐PET scanning.

RESULTS:

The median peak SUV was 4.5 (range, 1.4‐21.9). The survival curve was analyzed using the median peak SUV as the cutoff value. Comparison of each group and clinicopathologic characteristics revealed significant associations between peak SUV and each of the following factors: tumor status (P < .001), lymph node status (P < .001), metastatic status (P < .05), stage of disease (P < .001), number of PET‐positive lymph nodes (P < .001), and the number of histologically positive lymph nodes (P < .001). The 5‐year overall survival (OS) rate for patients having FDG uptake with a peak SUV ≥4.5 was 47% and that for patients with a peak SUV <4.5 was 76% (P < .0001). On multivariate survival analysis using the Cox proportional hazards model, peak SUV and the number of PET‐positive lymph nodes were found to be independent predictive factors for OS. The number of PET‐positive lymph nodes was a single prognostic factor predicting both disease‐free survival and OS.

CONCLUSIONS:

Pretreatment PET cannot only potentially diagnose the extent of disease, but also may be predictive of patient survival after esophageal cancer resection. Cancer 2009. © 2009 American Cancer Society.     

Accuracy of positron emission tomography/computed tomography and clinical assessment in the detection of complete rectal tumor regression after neoadjuvant chemoradiation: long-term results of a prospective trial (National Clinical Trial 00254683)

BACKGROUND:

Neoadjuvant chemoradiation (CRT) therapy may result in significant tumor regression in patients with rectal cancer. Patients who develop complete tumor regression have been managed by treatment strategies that are alternatives to standard total mesorectal excision. Therefore, assessment of tumor response with positron emission tomography/computed tomography (PET/CT) after neoadjuvant treatment may offer relevant information for the selection of patients to receive alternative treatment strategies.

METHODS:

Patients with clinical T2 (cT2) through cT4NxM0 rectal adenocarcinoma were included prospectively. Neoadjuvant therapy consisted of 54 grays of radiation and 5‐fluorouracil‐based chemotherapy. Baseline PET/CT studies were obtained before CRT followed by PET/CT studies at 6 weeks and 12 weeks after the completion of CRT. Clinical assessment was performed at 12 weeks after CRT completion. PET/CT results were compared with clinical and pathologic data.

RESULTS:

In total, 99 patients were included in the study. Twenty‐three patients were complete responders (16 had a complete clinical response, and 7 had a complete pathologic response). The PET/CT response evaluation at 12 weeks indicated that 18 patients had a complete response, and 81 patients had an incomplete response. There were 5 false‐negative and 10 false‐positive PET/CT results. PET/CT for the detection of residual cancer had 93% sensitivity, 53% specificity, a 73% negative predictive value, an 87% positive predictive value, and 85% accuracy. Clinical assessment alone resulted in an accuracy of 91%. PET/CT information may have detected misdiagnoses made by clinical assessment alone, improving overall accuracy to 96%.

CONCLUSIONS:

Assessment of tumor response at 12 weeks after CRT completion with PET/CT imaging may provide a useful additional tool with good overall accuracy for the selection of patients who may avoid unnecessary radical resection after achieving a complete clinical response. Cancer 2012;3501–3511. © 2011 American Cancer Society.     

18F‐Fluorodeoxyglucose positron emission tomography/computed tomography for the detection of recurrent bone and soft tissue sarcoma

BACKGROUND:

The clinical utility of modern hybrid imaging modalities for detecting recurrent bone or soft tissue sarcoma remains to be determined. In this report, the authors present a clinical study on the diagnostic accuracy and incremental value of integrated ¹⁸F‐fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F‐FDG PET/CT) in patients with a history of sarcoma who have clinically suspected disease recurrence.

METHODS:

Forty‐three patients who had a history of bone or soft tissue sarcoma and had documented complete remission underwent ¹⁸F‐FDG PET/CT. Image analysis was performed independently for ¹⁸F‐FDG PET (n = 43) and for contrast‐enhanced spiral CT (CE‐CT) (n = 30) by 2 separate readers, whereas combined ¹⁸F‐FDG PET/CT (n = 43) images were analyzed in consensus by both readers. Imaging findings were rated on a 5‐point scale and finally were reported as malignant, benign, or equivocal. Imaging findings were validated either by histopathology (n = 24) or by clinical follow‐up (n = 19).

RESULTS:

¹⁸F‐FDG PET/CT had greater sensitivity and specificity compared with CE‐CT alone (94% and 92% vs 78% and 67%, respectively), resulting in significantly greater accuracy (93% vs 73%; P = .03). ¹⁸F‐FDG PET/CT was particularly superior regarding detection of local recurrence or soft tissue lesions (sensitivity and specificity: 83% and 100% vs 50% and 100%, respectively) or bone metastases (100% and 100% vs 85% and 88%, respectively).

CONCLUSIONS:

¹⁸F‐FDG PET/CT had greater diagnostic accuracy in the detection of recurrent bone or soft tissue sarcoma compared with CE‐CT alone. The detection of local recurrence was the most evident advantage of ¹⁸F‐FDG PET/CT over CE‐CT. Cancer 2013. © 2012 American Cancer Society.     

Post-treatment (not interim) positron emission tomography-computed tomography scan status is highly predictive of outcome in mantle cell lymphoma patients treated with R-HyperCVAD

BACKGROUND:

Although convincing data exist regarding the prognostic utility of positron emission tomographic (PET)‐computed tomographic (CT) imaging in Hodgkin lymphoma and diffuse large B‐cell lymphoma, its prognostic utility both during treatment and immediately after treatment have not been systematically evaluated in a large mantle cell lymphoma (MCL) patient cohort to support its use in clinical practice.

METHODS:

The authors conducted a retrospective cohort study to examine the prognostic utility of PET‐CT imaging in a uniform MCL patient cohort undergoing dose‐intensive chemotherapy (R‐HyCVAD) in the frontline setting. The primary study endpoints were progression‐free survival (PFS) and overall survival (OS). PET‐CT images were centrally reviewed for the purposes of this study using standardized response criteria.

RESULTS:

Fifty‐three patients with advanced stage MCL with PET‐CT data were identified. With median follow‐up of 32 months, 3‐year PFS and OS estimates were 76% (95% confidence interval [CI], 64%‐84%) and 84% (95% CI, 72%‐90%), respectively. Interim PET‐CT status was not associated with PFS (hazard ratio [HR], 0.9; 95% CI, 0.3‐2.7; P = .8) or OS (HR, 0.6; 95% CI, 0.1‐2.9; P = .5). Post‐treatment PET‐CT status was statistically significantly associated with PFS (HR, 5.2; 95% CI, 2.0‐13.6; P = .001) and trended toward significant for OS (HR, 2.8; 95% CI, 0.8‐9.6; P = .07).

CONCLUSIONS:

These data do not support the prognostic utility of PET‐CT in pretreatment and interim treatment settings. A positive PET‐CT after the completion of therapy identifies a patient subset with an inferior PFS and a trend toward inferior OS. Cancer 2012;3565–3570. © 2011 American Cancer Society.     

Coregistered whole body magnetic resonance imaging‐positron emission tomography (MRI‐PET) versus PET‐computed tomography plus brain MRI in staging resectable lung cancer

BACKGROUND:

The objective of this study was to assess whether coregistered whole brain (WB) magnetic resonance imaging‐positron emission tomography (MRI‐PET) would increase the number of correctly upstaged patients compared with WB PET‐computed tomography (PET‐CT) plus dedicated brain MRI in patients with nonsmall cell lung cancer (NSCLC).

METHODS:

From January 2010 through November 2011, patients with NSCLC who had resectable disease based on conventional staging were assigned randomly either to coregistered MRI‐PET or WB PET‐CT plus brain MRI (ClinicalTrials.gov trial NCT01065415). The primary endpoint was correct upstaging (the identification of lesions with higher tumor, lymph node, or metastasis classification, verified with biopsy or other diagnostic test) to have the advantage of avoiding unnecessary thoracotomy, to determine appropriate treatment, and to accurately predict patient prognosis. The secondary endpoints were over staging and under staging compared with pathologic staging.

RESULTS:

Lung cancer was correctly upstaged in 37 of 143 patients (25.9%) in the MRI‐PET group and in 26 of 120 patients (21.7%) in the PET‐CT plus brain MRI group (4.2% difference; 95% confidence interval, ?6.1% to 14.5%; P = .426). Lung cancer was over staged in 26 of 143 patients (18.2%) in the MRI‐PET group and in 7 of 120 patients (5.8%) in the PET‐CT plus brain MRI group (12.4% difference; 95% confidence interval, 4.8%‐20%; P = .003), whereas lung cancer was under staged in 18 of 143 patients (12.6%) and in 28 of 120 patients (23.3%), respectively (?10.7% difference; 95% confidence interval, ?20.1% to ?1.4%; P = .022).

CONCLUSIONS:

Although both staging tools allowed greater than 20% correct upstaging compared with conventional staging methods, coregistered MRI‐PET did not appear to help identify significantly more correctly upstaged patients than PET‐CT plus brain MRI in patients with NSCLC. Cancer 2013. © 2013 American Cancer Society.     

Analysis of morbidity and clinical implications of laparoscopic para-aortic lymphadenectomy in a continuous series of 98 patients with advanced-stage cervical cancer and negative PET-CT imaging in the para-aortic area

Background.

Laparoscopic para-aortic lymphadenectomy (PAL) is being used increasingly to stage patients with locally advanced cervical cancer (LACC) and to define radiation field limits before chemoradiation therapy (CRT). This study aimed to define clinical implications, review complications, and determine whether surgical complications delayed the start of CRT.

Methods.

We retrospectively reviewed a continuous series of patients with LACC, with no positive para-aortic (PA) nodes on positron emission tomography–computed tomography (PET–CT) and who had undergone a primary laparoscopic PAL.

Results.

From November 2007 to June 2010, 98 patients with LACC underwent pretherapeutic PAL. Two patients did not undergo PAL: extensive carcinomatosis was discovered in one case and a technical problem arose in the other. No perioperative complications occurred. Seven patients had a lymphocyst requiring an imaging-guided (or laparoscopic) puncture. Eight patients (8.4%, which corresponds to the false-negative PET–CT rate) had metastatic disease within PA lymph nodes. In cases of suspicious pelvic nodes on PET–CT, the risk for PA nodal disease was greater (24.0% versus 2.9%). When patients with and without surgical morbidity were compared, the median delay to the start of treatment was not significantly different (15 days; range, 3–49 days versus 18 days; range, 3–42 days).

Conclusions.

The morbidity of laparoscopic PAL was limited and the completion of treatment was not delayed when complications occurred. Nevertheless, if PET–CT of the pelvic area is negative, the interest in staging PAL could be discussed because the risk for PA nodal disease is very low.     

Characteristics of thyroid incidentalomas detected by pre-treatment [18F]FDG PET or PET/CT in patients with cervical cancer

Objective

Considering the increased use of [¹⁸F]FDG PET or PET/CT, the clinical significance of thyroid incidentalomas is the subject of controversy. The aim of this study was to determine the incidence of malignancies associated with thyroid incidentalomas detected by pre-treatment PET or PET/CT in patients with cervical cancer.

Methods

We retrospectively reviewed the medical records of patients with cervical cancer who had thyroid incidentalomas detected by pre-treatment PET or PET/CT and were treated at our institute between January 2001 and December 2009.

Results

Of 327 patients who underwent pre-treatment PET or PET/CT, 33 patients had thyroid incidentalomas (10.1%) and 4 patients were diagnosed with thyroid malignancies by percutaneous needle aspiration (PCNA) or surgery. To put it concretely, of 33 patients with thyroid incidentaloma, 16 patients had a diffuse uptake and 17 patients had a focal uptake. Four of 17 patients with focal uptake were diagnosed with thyroid malignancies (23.5%). One patient with a focal uptake had an atypical cell based on PCNA, but did not undergo additional studies. The mean SUV_max of thyroid malignancies did not differ from that of benign thyroid diseases.

Conclusion

Thyroid incidentalomas are frequently detected by pre-treatment PET or PET/CT in patients with cervical cancer. Focal uptake on PET or PET/CT has a high risk of thyroid cancer.     

Impact of post-therapy positron emission tomography on prognostic stratification and surveillance after chemoradiotherapy for cervical cancer

BACKGROUND:

A study was undertaken to investigate the detection of relapse and survival outcomes in patients with cervical cancer treated with curative intent chemoradiotherapy, and evaluated with a post‐therapy ¹⁸F‐fluorodeoxyglucose positron emission tomography (FDG‐PET) scan.

METHODS:

Between January 2002 and June 2007, 105 consecutive patients were prospectively enrolled into a registry study designed to assess outcomes of chemoradiotherapy. A FDG‐PET scan was performed between 3 and 12 months (median, 4.9 months) post‐treatment at clinician discretion. Tumor response was graded as complete metabolic response, partial metabolic response, or progressive metabolic disease.

RESULTS:

Median follow‐up was 36 months. At post‐therapy FDG‐PET, 73 (70%) patients had complete metabolic response, 10 (9%) had partial metabolic response, and 22 (21%) had progressive metabolic disease. Overall survival at 3 years was 77% in all patients, and 95% for those with complete metabolic response. On multivariate analysis, complete metabolic response (P < .0001) and pretreatment tumor volume (P = .041) were strong predictors for overall survival. The number of involved lymph nodes (P < .005) and International Federation of Gynecology and Obstetrics stage (P = .04) were predictive of relapse‐free survival. In total, 18 patients relapsed at a single site, and 13 underwent salvage, with a 3‐year survival of 67%. Patients with complete metabolic response had a distant failure rate 36‐fold less than those with partial metabolic response (P < .0001). After complete metabolic response, only 1 patient (1.6%) relapsed without symptoms and was detected through physical examination.

CONCLUSIONS:

The presence of a complete metabolic response at post‐therapy FDG‐PET is a powerful predictor for survival after chemoradiation. The very low rate of recurrence in patients with a complete metabolic response justifies a conservative follow‐up approach for these patients, because relapse is usually symptomatic and not detected by routine clinical review. Cancer 2011. © 2011 American Cancer Society.     

A prospective evaluation of the utility of 2‐deoxy‐2‐[18F]fluoro‐D‐glucose positron emission tomography and computed tomography in staging locally advanced gastric cancer

BACKGROUND:

The aim of this study was to examine prospectively the utility of adding preoperative [¹⁸F]fluorodeoxyglucose positron emission tomography (FDG‐PET)/computed tomography (CT) to routine CT, endoscopic ultrasound (EUS), and laparoscopic staging of localized gastric cancer.

METHODS:

Patients with locally advanced gastric/gastroesophageal cancer were screened for 2 institutional review board–approved Memorial Sloan‐Kettering Cancer Center neoadjuvant chemotherapy protocols. Locally advanced disease was defined as T3 or T4, or lymph node–positive, based on EUS and high‐resolution CT scan. All patients underwent both standard FDG‐PET/CT and laparoscopy with cytological examination of washings. The sensitivity and specificity of FDG‐PET/CT for the identification of metastatic disease not seen on CT was determined. An economic model using Medicare/Medicaid reimbursement charges was developed to assess the cost‐effectiveness of these interventions.

RESULTS:

A total of 113 patients were enrolled from 2003 to 2010. All patients were assessed as having locally advanced disease by CT/EUS. FDG uptake in the primary tumor was associated with male sex, proximal tumors, and nondiffuse Lauren's subtype. 31 (27%) patients had occult metastatic disease detected by PET/CT (n = 11, 10%) and/or laparoscopy (n = 21, 19%), with a single overlap. Economic modeling suggests that the addition of FDG‐PET/CT to the standard staging evaluation of patients with locally advanced gastric cancer resulted in an estimated cost savings of ～US $13,000 per patient.

CONCLUSIONS:

FDG‐PET/CT identifies occult metastatic lesions in approximately 10% of patients with locally advanced gastric cancer. Because of reduced morbidity from fewer futile surgeries and lower patient care costs, PET/CT should be considered as a component of the standard staging algorithm for localized gastric cancer. Cancer 2012. © 2012 American Cancer Society.     

Detection of hematogenous bone metastasis in cervical cancer

BACKGROUND:

In this large‐scale, retrospective study, the authors evaluated the diagnostic performances of computed tomography (CT), magnetic resonance (MR) imaging, and ¹⁸F‐fluorodeoxyglucose‐positron emission tomography (¹⁸F‐FDG–PET) in detecting hematogenous bone metastasis in patients with cervical cancer. The associated risk factors also were analyzed.

METHODS:

Patients with invasive cervical cancer who had both ¹⁸F‐FDG–PET studies and CT or MR imaging studies were selected. Patients who had either International Federation of Gynecology and Obstetrics (FIGO) stage III/IV disease or positive lymph node metastasis at the time of primary staging and patients who had suspected recurrent disease were included in the analyses. The diagnostic performances of PET was compared with the performance of CT and MR imaging by using the area under the receiver‐operating‐characteristic curve (AUC). Both univariate and multivariate analyses were applied to assess the risk factors for hematogenous bone metastasis at primary staging.

RESULTS:

PET was more sensitive than CT (P = .004) and was more specific than MR imaging (P = .04). The diagnostic performance of PET was significantly superior to the performance CT (AUC, 0.964 vs 0.662; P < .001) and MR (AUC, 0.966 vs 0.833; P = .033). Both FIGO stage and the extent of lymph node metastases were associated with hematogenous bone metastasis in univariate analysis. However, the extent of lymph node metastases was the only significant risk factor in multivariate analysis (P = .025).

CONCLUSIONS:

The current study demonstrated the superiority of ¹⁸F‐FDG–PET over CT and MR imaging for detecting hematogenous bone metastasis in patients with advanced cervical cancer. Hematogenous bone metastasis in cervical cancer was associated with the extent of lymph node metastases rather than with FIGO stage. Cancer 2009. © 2009 American Cancer Society.     

[F‐18]‐fluorodeoxy‐D‐glucose–positron emission tomography response is associated with outcome for extremity osteosarcoma in children and young adults

BACKGROUND:

Response to neoadjuvant chemotherapy is 1 of the most powerful prognostic factors for extremity osteosarcoma. [F‐18]‐fluorodeoxy‐D‐glucose–positron emission tomography (FDG‐PET) is a noninvasive imaging modality that is used to predict histopathologic response. To determine the prognostic value of FDG‐PET response for progression‐free survival (PFS) in osteosarcoma, the authors of this report reviewed the University of Washington Medical Center experience.

METHODS:

Forty patients with extremity osteosarcoma were evaluated by FDG‐PET. All patients received neoadjuvant and adjuvant chemotherapy. FDG‐PET standard uptake values (SUVs) before neoadjuvant chemotherapy (SUV1) and after neoadjuvant chemotherapy (SUV2) were analyzed and correlated with histopathologic response.

RESULTS:

The median SUV1 was 6.8 (range, 3.0‐24.1), the median SUV2 was 2.3 (range, 1.2‐12.8), and the median SUV2 to SUV1 ratio (SUV2:1), was 0.36 (range, 0.12‐1.10). A good FDG‐PET response was defined as anSUV2 <2.5 or an SUV2:1 ≤0.5. FDG‐PET responses according to SUV2 and SUV2:1 were concordant with histologic response in 58% and 68% of patients, respectively. SUV2 was associated with outcome (4‐year PFS, 73% for SUV2 <2.5 vs 39% for SUV2 ≥2.5; P = .021). Both the initial disease stage and the histologic response were associated with outcome.

CONCLUSIONS:

FDG‐PET imaging of extremity osteosarcoma was correlated only partially with a histologic response to neoadjuvant chemotherapy. An SUV2 <2.5 was associated with improved PFS. Future prospective studies are warranted to determine whether FDG‐PET imaging may be used as a predictor of outcome independent of initial disease stage. Cancer 2009. © 2009 American Cancer Society.     

18F‐fluorodeoxyglucose positron emission tomography/computed tomography (FDG‐PET/CT) imaging in the staging and prognosis of inflammatory breast cancer

BACKGROUND:

To prospectively assess fluorodeoxyglucose positron emission tomography/computed tomography (FDG‐PET/CT) staging and prognosis value in patients with suspected inflammatory breast cancer (IBC).

METHODS:

Sixty‐two women (mean age 50.7 ± 11.4 years) presenting with unilateral inflammatory breast tumors (59 invasive carcinomas; 3 mastitis) underwent a PET/CT scan before biopsy.

RESULTS:

PET/CT scan was positive for the primary malignant tumor in 100% and false positive in 2 of 3 benign mastitis. In 59 IBC patients, FDG nodal foci were detected in axillary (90%; n = 53) and extra‐axillary areas (56%; n = 33) ipsilateral to the cancer. Compared with clinical examination, the axillary lymph node status by PET/CT was upstaged and downstaged in 35 and 5 patients, respectively. In 7 of 9 N0 patients, the axillary lymph node positivity on PET/CT was correct, as revealed by pathological postsurgery assessment (not available in the 2 remaining patients). The nodal foci were compared with preoperative fine needle aspiration and/or pathological postchemotherapy findings available in 44 patients and corresponded to 38 true positive, 4 false‐negative, and 2 false‐positive cases. In 18 of 59 IBC patients (31%), distant lesions were found. On the basis of a univariate analysis of the first enrolled patients (n = 42), among 28 patients who showed intense tumoral uptake (standard uptake value_max>5), the 11 patients with distant lesions had a worse prognosis than the 17 patients without distant lesions (P = .04).

CONCLUSIONS:

FDG‐PET/CT imaging provides additional invaluable information regarding nodal status or distant metastases in IBC patients and should be considered in the initial staging. It seems also that some prognostic information can be derived from FDG uptake characteristics. Cancer 2009. © 2009 American Cancer Society.     

Prevalence of non 18F‐fluorodeoxyglucose‐avid incidental findings of clinical significance on whole body positron emission tomography/computed tomography: A review of 500 consecutive cases

Introduction

The prevalence of incidental ¹⁸F‐fluorodeoxyglucose (FDG)‐avid findings on positron emission tomography–computed tomography (PET/CT) has been extensively described. Few studies, however, have assessed the prevalence and significance of non‐FDG‐avid findings; pathology that is identified on review of the low‐dose, non‐contrast CT. The aim of this study was to determine the overall prevalence of non FDG‐avid incidental findings on PET/CT and the prevalence of ‘clinically significant’ non FDG‐avid pathology.

Methods

Five hundred consecutive whole body PET/CT studies performed in 2016 at a university affiliated tertiary hospital were retrospectively reviewed by two radiologists experienced in reporting PET/CT. Findings were categorized according to potential clinical relevance, and a targeted follow‐up of clinically significant incidental findings was performed.

Results

Incidental findings were encountered in 463 of 500 (92.6%) patients. In 226 patients, these findings had been detected on previous imaging studies, with unknown incidental findings present in 237 of 500 (47.4%) patients. 113 of 500 (22.6%) patients had non‐avid incidental findings of potentially major clinical significance, and in 35 patients (7.0%) these findings were considered previously unknown. The most common non‐avid findings of potentially major significance were pulmonary nodules (6 mm or larger), moderate or large size pleural effusions, and vascular aneurysms. Unknown incidental findings of potentially major clinical significance were significantly higher in patients imaged for melanoma staging (P= 0.004).

Conclusion

The prevalence of incidental findings of clinical significance that do not accumulate FDG in PET/CT is not insignificant. Routine systematic review of the low‐dose CT is required to avoid missing potentially clinically important findings, in particular pleural effusions, vascular aneurysms and metastatic pulmonary nodules.