Prognostic significance of baseline positron emission tomography and importance of clinical complete response in patients with esophageal or gastroesophageal junction cancer treated with definitive chemoradiotherapy

BACKGROUND:

Metabolic imaging is of interest in esophageal cancer; however, the usefulness of initial standardized uptake value (SUV) in positron emission tomography (PET) is unknown in patients with esophageal or gastroesophageal carcinoma treated with definitive chemoradiotherapy. The authors hypothesized that initial SUV would correlate with patient outcome.

METHODS:

The authors retrospectively analyzed esophageal or gastroesophageal carcinoma patients who had baseline PET and endoscopic ultrasonography in addition to other routine staging. All patients received definitive chemoradiotherapy. Multiple statistical methods were used.

RESULTS:

The authors analyzed 209 consecutive esophageal or gastroesophageal carcinoma patients treated with definitive chemoradiation for outcome; of these, 180 had baseline PET for additional analyses. The median overall survival (OS) for all patients was 20.7 months (95% confidence interval, 18.8‐26.3). Patients with clinical complete response (CR) lived longer than those with less than clinical CR (P < .0001). The median initial SUV was 12.7 (range, 0‐51). Higher initial SUV was associated with longer tumors (P = .0001), higher T‐stage status (P < .0001), positive N‐stage status (P = .0001), higher overall stage (P < .0001), lack of clinical CR (P = .0002), and squamous cell histology (P < .0001). In the univariate analysis, initial SUV was associated with OS (Cox model, P = .016; log‐rank test, P = .002). In the multivariate analysis, initial SUV dichotomized by the median value (P = .024) and tumor grade (P = .016) proved to be independent OS prognosticators. Median initial SUV for clinical CR patients was 10.2, compared with 15.3 for less than clinical CR patients (P = .0058).

CONCLUSIONS:

The data indicate that a higher initial SUV is associated with poorer OS in patients with esophageal or gastroesophageal carcinoma receiving definitive chemoradiation. Upon validation, baseline PET may become a useful stratification factor in randomized trials and for individualizing therapy. Cancer 2011;. © 2011 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.     

Laparoscopic extraperitoneal para-aortic lymphadenectomy in locally advanced cervical cancer: a prospective correlation of surgical findings with positron emission tomography/computed tomography findings

BACKGROUND:

Failure to detect metastasis to para‐aortic nodes in patients with locally advanced cervical cancer leads to suboptimal treatment. No previous studies have prospectively compared positron emission tomography (PET)/computed tomography (CT) with laparoscopic extraperitoneal staging in the evaluation of para‐aortic lymph nodes.

METHODS:

Sixty‐five patients were enrolled; 60 were available for analysis. Patients with stage IB2‐IVA cervical cancer without evidence of para‐aortic lymphadenopathy on preoperative CT or magnetic resonance imaging (MRI) were prospectively enrolled. All patients underwent preoperative PET/CT. Laparoscopic extraperitoneal lymphadenectomy was performed from the common iliac vessels to the left renal vein.

RESULTS:

The median age at diagnosis was 48 years (range, 23‐84). The median operative time was 140 minutes (range, 89‐252). The median blood loss was 22.5 mL (range, 5‐150). The median length of hospital stay was 1 day (range, 0‐4). The median number of lymph nodes retrieved was 11 (range, 1‐39). Fourteen (23%) patients had histopathologically positive para‐aortic nodes. Of the 26 patients with negative pelvic and para‐aortic nodes on PET/CT, 3 (12%) had histopathologically positive para‐aortic nodes. Of the 27 patients with positive pelvic but negative para‐aortic nodes on PET/CT, 6 (22%) had histopathologically positive para‐aortic nodes. The sensitivity and specificity of PET/CT in detecting positive para‐aortic nodes when nodes were negative on CT or MRI were 36% and 96%, respectively. Eleven (18.3%) patients had a treatment modification based on surgical findings.

CONCLUSIONS:

Laparoscopic extraperitoneal para‐aortic lymphadenectomy is safe and feasible. Surgical staging of patients with locally advanced cervical cancer should be considered before planned radiation and chemotherapy. Cancer 2011. © 2010 American Cancer Society.     

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.     

Influence of the baseline 18F‐fluoro‐2‐deoxy‐D‐glucose positron emission tomography results on survival and pathologic response in patients with gastroesophageal cancer undergoing chemoradiation

BACKGROUND:

In patients with esophageal cancer who receive chemoradiation, tools to predict/prognosticate outcome before administering therapy are lacking. The authors evaluated initial standardized unit value (iSUV) of 18F‐fluoro‐2‐deoxy‐D‐glucose positron emission tomography and its association with overall survival and the degree of pathologic response after surgery.

METHODS:

The authors analyzed 161 patients with esophageal adenocarcinoma who had chemoradiation followed by surgery. The log‐rank test, univariate Cox proportional hazards model, Kaplan‐Meier survival plot, and Fisher exact test were used to analyze dichotomized iSUV and its association with overall survival and pathologic response.

RESULTS:

The median age of 161 patients was 61 years (range, 26‐80 years) and the majority of patients had lower esophageal or gastroesophageal junction involvement. All patients received fluoropyrimidine and, most commonly, a taxane or platinum compound with concomitant radiation. The median radiation dose was 45 grays (Gy) (range, 45 Gy‐50.4 Gy). The median iSUV for all patients was 10.1 (range, 0‐58). Using the Fisher exact test, iSUV was not found to be associated with the location of the primary cancer. iSUV higher than the median (10.1) was associated with a better pathologic response (P = .06). Patients with primary cancer with iSUV >10.1 had a lower risk for death (hazards ratio of 0.56) compared with those with iSUV ≤10.1. Higher iSUV was nonsignificantly associated with improved survival (P = .07).

CONCLUSIONS:

Data from the current study suggest that lower iSUV is associated with poor survival and lower probability of response to chemoradiation. iSUV needs to be further evaluated because it may be used to complement other imaging or biomarker assessments to individualize therapy. Cancer 2009. © 2009 American Cancer Society.     

Imaging tumour hypoxia with positron emission tomography

Hypoxia, a hallmark of most solid tumours, is a negative prognostic factor due to its association with an aggressive tumour phenotype and therapeutic resistance. Given its prominent role in oncology, accurate detection of hypoxia is important, as it impacts on prognosis and could influence treatment planning. A variety of approaches have been explored over the years for detecting and monitoring changes in hypoxia in tumours, including biological markers and noninvasive imaging techniques. Positron emission tomography (PET) is the preferred method for imaging tumour hypoxia due to its high specificity and sensitivity to probe physiological processes in vivo, as well as the ability to provide information about intracellular oxygenation levels. This review provides an overview of imaging hypoxia with PET, with an emphasis on the advantages and limitations of the currently available hypoxia radiotracers.     

Characteristics of advantages of positron emission tomography over computed tomography for N-staging in lung cancer patients

OBJECTIVE: We analyzed the characteristics of advantages of positron emission tomography (PET) over computed tomography (CT) for N-staging in lung cancer patients. METHODS: Preoperative PET and CT scans were performed for 2057 lymph node stations in 205 patients with peripheral-type lung cancer. The advantages of PET over CT for N-staging were analyzed among lymph node locations and histological subtypes. RESULTS: The pathological N-stages were N0 in 143 patients, N1 in 31, N2 in 24 and N3 in 7. PET was able to diagnose N0, N2 and N3 diseases more accurately than CT (P=0.03, 0.01 and 0.02, respectively), but there was no significant difference between the two modalities for N1 disease. In the upper mediastinal lymph node stations, both false-negative and false-positive were significantly less frequent with PET than with CT (P=0.001). In the lower mediastinal and supra clavicle lymph nodes, PET showed a lower frequency of false-negative than CT (P=0.04 and 0.003, respectively), but there was no significant difference in the frequency of false-positive between the two modalities. Among histological types, PET could stage adenocarcinoma with less frequent false-negative and squamous cell carcinoma with less frequent false-positive than CT (P=0.02 and 0.005, respectively). CONCLUSION: For N-staging, PET was superior to CT for the following: (1) more accurate for N0, N2 and N3 diseases but not for N1; (2) lower frequency of false-positive in the upper mediastinal nodes; and (3) lower frequencies of false-negative in adenocarcinoma and false-positive in squamous cell carcinoma. Recognizing these advantages of PET could make the N-staging of lung cancer more accurate.     

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.     

Fluorodeoxyglucose positron emission tomography in the evaluation of germ cell tumours at relapse

Differentiation of active disease from fibrosis/mature teratoma in patients with residual masses or identifying of sites of recurrence in patients with raised markers following treatment of their testicular cancer remains a problem.(18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) has the potential to identify active disease and thereby influence further management in these patients. We performed a retrospective study of the use of FDG-PET in detecting residual/recurrent testicular carcinoma in 55 patients (seventy FDG-PET scans). Forty-seven scans were for the assessment of residual masses (18 had raised markers) and 23 scans were for the investigation of raised markers in the presence of normal CT scans. True positive results were based on positive histology or clinical follow-up. FDG-PET had a positive predictive value (PPV) of 96% and a negative predictive value (NPV) of 90% in patients with residual masses. This PPV was equivalent to that of markers (94%) but FDG-PET had the advantage of identifying the site of that recurrence. The NPV was higher than that of markers. In patients with raised markers alone the PPV of FDG-PET was 92% but the NPV was only 50%. However, subsequent FDG-PET imaging was frequently the first imaging modality to identify the site of disease. FDG-PET effected a management change in 57% of cases. FDG-PET scanning detected viable tumour in residual masses and identified sites of disease in suspected recurrence.     

Evaluating the role of fluorodeoxyglucose positron emission tomography-computed tomography in multi-disciplinary team recommendations for oesophago-gastric cancer

Background:

National guidelines recommend that fluorodeoxyglucose positron emission tomography-computed tomography (PET-CT) is performed in all patients being considered for radical treatment of oesophageal or oesophago-gastric cancer without computerised tomography scan (CTS) evidence of metastasis. Guidance also mandates that all patients with cancer have treatment decisions made within the context of a multi-disciplinary team (MDT) meeting. Little is known, however, about the influence of PET-CT on decision making within MDTs. The aim of this study was to assess the role of PET-CT in oesophago-gastric cancer on MDT decision making.

Methods:

A retrospective analysis of a prospectively held database of all patients with biopsy-proven oesophageal or oesophago-gastric cancer discussed by a specialist MDT was interrogated. Patients selected for radical treatment without CTS evidence of M1 disease were identified. The influence of PET-CT on MDT decision making was examined by establishing whether the PET-CT confirmed CTS findings of M0 disease (and did not change the patient staging pathway) or whether the PET-CT changed the pathway by showing unsuspected M1 disease, refuting CTS suspicious metastases, or identifying another lesion (needing further investigation).

Results:

In 102 MDT meetings, 418 patients were discussed, of whom 240 were initially considered for radical treatment and 238 undergoing PET-CT. The PET-CT confirmed CTS findings for 147 (61.8%) and changed MDT recommendations in 91 patients (38.2%) by (i) identifying M1 disease (n=43), (ii) refuting CTS suspicions of M1 disease (n=25), and (iii) identifying new lesions required for investigations (n=23).

Conclusion:

The addition of PET-CT to standard staging for oesophageal cancer led to changes in MDT recommendations in 93 (38.2%) patients, improving patient selection for radical treatment. The validity of the proposed methods for evaluating PET-CT on MDT decision making requires more work in other centres and teams.     

A study on the clinical value of 18F-fluorodeoxyglucose positron emission tomography/computed tomography combined with serum squamous cell carcinoma antigen in diagnosing recurrence/metastases in patients with early metaphase cervical cancer

Cervical cancer (CC) is the most common female genital tract malignancy, with repercussions on the psychophysiological health of female patients. Patients with CC are faced with a high risk of postoperative recurrence and metastases. The present study aimed to evaluate the clinical value of 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) combined with serum squamous cell carcinoma antigen (SCC-Ag) in the diagnosis of postoperative recurrence/metastases in patients with early stage CC. This was a prospective follow-up study on 246 patients who received surgery for early stage CC. The results of clinical follow-up and pathological examination were taken as the gold standard. The diagnostic sensitivity, specificity, positive predictive value, negative predictive value and area under the receiver operating characteristic (ROC) curve were calculated for PET/CT, serum SCC-Ag determination and the combined PET/CT and serum SCC-Ag method. Results demonstrated that 90.11% patients completed the follow-up, and the median follow-up time was 22 months (range, 7–42 months). Tumor recurrence or metastasis was confirmed in a total of 137 patients (55.7%), including 18 deaths. The diagnostic sensitivity of PET/CT scan combined with serum SCC-Ag determination for postoperative metastases/recurrence in patients with early stage CC was 93.43% (95% CI, 0.875–0.967). The specificity was 92.67% (95% CI, 0.856–0.965), the positive predictive value was 94.12% (95% CI, 0.884–0.972), the negative predictive value was 91.81% (95% CI, 0.846–0.959) and the area under the ROC curve was 0.930±0.019 (95% CI, 0.893–0.968; P<0.001). The results also revealed that the serum SCC-Ag level was positively correlated with SUVmax (r=0.458; P<0.001). The results from the present study demonstrated that for patients with early metaphase CC, PET/CT scan combined with serum SCC-Ag determination during the follow-up was capable of earlier, more comprehensive and more accurate detection of recurrence/metastatic lesions, which is of high clinical application value.     

Detection of occult bone metastases of lung cancer with Fluorine‐18 fluorodeoxyglucose positron emission tomography

Accurate staging of cancer has a critical role in optimal patient management. Fluorine‐18 fluorodeoxyglucose positron emission tomography (FDG PET) is superior to CT in the detection of local and distant metastases in patients with non‐small cell lung cancer. Although Tc‐99 m methylene diphosphonate (MDP) bone scanning is well established in the evaluation of bone metastases, there are conflicting reports on the use of FDG PET in the evaluation of skeletal metastases. We report on a patient with locally advanced lung carcinoma in whom FDG PET accurately identified previously unsuspected widespread asymptomatic bone metastases (bone scan and X‐rays negative, confirmed on MRI). Assessment of glucose metabolism with FDG PET might represent a more powerful tool to detect bone metastases in lung cancer compared with conventional bone scans.     

18-fluorodeoxy-glucose positron emission computed tomography as predictive of response after chemoradiation in oesophageal cancer patients

IntroductionThe purpose of this study was to evaluate if a baseline, an interim or a post-chemoradiation (CTRT) 18-fluorodeoxy-glucose positron emission computed tomography (18F-FDG PET/CT) studies could provide information on pathologic response to CTRT and overall survival (OS).Materials and methodsThirty-one patients with histologically proven adenocarcinoma or squamous cell carcinoma of the oesophagus, fit for trimodality therapy were prospectively enrolled. Most were men (93.5%), and had a stage III cancer (74.2%). Chemotherapy consisted of oxaliplatin/5-fluorouracil (45.2%) and taxane/5-fluorouracil (54.8%). All patients underwent a baseline, an interim (performed 12 ± 2 days after the onset of CTRT) and a post-CTRT 18F-FDG PET/CT study. The 18F-FDG PET/CT variables evaluated were at baseline, interim and post-CTRT studies maximum standardised uptake value (SUVmax) and total lesion glycolysis (TLG). Clinical and 18F-FDG PET/CT parameters were correlated with pathologic complete response (pathCR) and OS.ResultsAmong the 31 patients studied, 61.3% achieved a clinical complete response (cCR) and 87.1% had surgery. The median OS was 35.1 months (95% confidence interval (CI): 19.9–NA). PathCR rate was 22.2%. There was only a marginal association between cCR and pathCR (p = 0.06). None of the other variables was predictive of pathCR. There was association between OS and baseline TLG (p = 0.03) at the optimal cutoff TLG value of 75.15. Additionally, TLG and ΔTLG post-CTRT were also associated with OS (p = 0.01 and 0.03, respectively).ConclusionNone of the PET parameters is predictive of pathCR but TLG at baseline and post-CTRT are prognostic of OS.     

Pretransplant positive positron emission tomography/gallium scans predict poor outcome in patients with recurrent/refractory Hodgkin lymphoma

BACKGROUND: The objective was to determine the prognostic value of functional imaging (FI) in predicting outcome of patients with recurrent/refractory Hodgkin lymphoma (HL) before undergoing high-dose chemotherapy with autologous stem cell transplantation (ASCT). METHODS: Clinical and imaging data were retrospectively reviewed in 211 consecutive patients treated with ASCT from February 1993 to May 2004. The FI results were correlated with progression-free survival (PFS) and overall survival (OS) using Kaplan-Meier survival analysis. RESULTS: Responses were assessed by conventional criteria and evaluated by positron emission tomography (PET) (n = 68) and gallium scans (n = 144) before ASCT. A complete response (CR) or unconfirmed CR (CRu) was seen in 51% of patients, a partial response (PR) in 41% of patients, and stable or progressive disease in 7% of patients. FI was positive in only 6 of 110 (5%) of CR/CRu patients, in 48 of 86 (56%) of PR patients, and in all 3 patients with progressive disease. The 3-year PFS was 69% for patients with negative FI versus 23% for patients with positive FI (P < .0001). The 3-year OS rates were 87% and 58%, respectively (P < .0001). The 3-year PFS for patients in PR with negative FI was 51% comparable to patients in CR (76%) versus 27% for patients in PR with positive FI (P < .0001). In a multivariate model, positive FI was found to be independently prognostic of PFS. CONCLUSIONS: Pretransplant FI status predicts outcome in patients with recurrent/refractory HL. Positive FI confers a poor prognosis, independent of other traditional presalvage prognostic factors.     

Pancreatic cancer: Preliminary experience with sodium iodide fluorodeoxyglucose positron emission tomography in Australia

Previous studies of fluorodeoxyglucose positron emission tomography (FDG‐PET) in pancreatic cancer have used Bismuth Germinate detector systems. This preliminary Australian study aims to confirm the accuracy of FDG‐PET in pancreatic cancer using a dedicated sodium iodide (NaI) PET system. Fifteen consecutive patients underwent FDG‐PET using a GE QUEST dedicated NaI PET scanner. The indications were the characterization of a pancreatic mass seen on CT or ultrasonographic imaging (nine cases), diagnosis or exclusion of recurrent disease following surgery and adjuvant therapy (four cases) and presurgical staging of primary pancreatic cancer (two cases). The final diagnosis was determined from histology or, when no histology was available, by radiological and clinical follow up. The FDG‐PET accurately characterized eight out of nine pancreatic masses (seven were true negative, one was true positive and one was false positive). Of the four cases performed to determine recurrent disease, three were accurately diagnosed (two true negatives and one true positive). In the fourth case, PET accurately detected a liver metastasis but did not detect the local recurrence. Results in the two cases where PET was performed for preoperative staging comprised one true positive and one false negative. Sodium iodide FDG‐PET is useful in the diagnosis of pancreatic cancer, particularly in the presence of a previously detected mass.     

Value of integrated positron emission tomography revised using a phantom study to evaluate malignancy grade of lung adenocarcinoma

BACKGROUND:

The malignant biological behavior of small‐sized lung adenocarcinomas remains obscure, although understanding this feature is important for selecting appropriate treatment. In the current study, the authors evaluated malignancy grades of small adenocarcinomas using fluorodeoxyglucose‐positron emission tomography/computed tomography (PET/CT) in addition to high‐resolution CT (HRCT) and pathological analysis in a multicenter setting.

METHODS:

A total of 201 patients with clinical T1N0M0 adenocarcinoma underwent PET/CT and HRCT followed by complete surgical resection. Associations between components of bronchioloalveolar carcinoma (BAC) in specimens and maximum standardized uptake values (maxSUV) on PET/CT and ground‐glass opacity (GGO) ratios and tumor disappearance rate (TDR) on HRCT were analyzed, as well as associations between these findings and pathological features of the tumors. Variations in maxSUV among institutions and the underestimations derived from small tumors, which are limitations of PET performed in multicenter studies, were adjusted using a phantom study.

RESULTS:

The maxSUV, BAC ratio, TDR, and GGO ratio (in that order) reflected the grade of tumor invasiveness and lymph node metastasis. The maxSUV and BAC ratio were found to be significant prognostic predictors derived from disease‐free survival curves. Although the BAC ratio was found to be significantly associated with preoperative radiographic parameters, the maxSUV, GGO ratio, and TDR (all P < .0001), the degree of correlation with maxSUV (correlation coefficient [R²] = 0.1699) was much weaker than that reported with the GGO ratio (R² = 0.5860) or TDR (R² = 0.5082).

CONCLUSIONS:

Phantom studies can overcome the difficulties of multicenter studies using PET. A higher maxSUV appears to reflect aggressive malignant behavior in clinical T1N0M0 adenocarcinomas, independent of BAC components. Preoperative PET/CT assessment in addition to HRCT could be used to construct hypotheses for a future clinical study of strategies for the treatment of patients with small lung adenocarcinoma. Cancer 2010. © 2010 American Cancer Society.     

Influence of 18F‐fluorodeoxyglucose‐positron emission tomography on computed tomography‐based radiation treatment planning for oesophageal cancer

The addition of positron emission tomography (PET) information to CT‐based radiotherapy treatment planning has the potential to improve target volume definition through more accurate localization of the primary tumour and involved regional lymph nodes. This case report describes the first patient enrolled to a prospective study evaluating the effects of coregistered positron emission tomography/CT images on radiotherapy treatment planning for oesophageal cancer. The results show that if combined positron emission tomography/CT is used for radiotherapy treatment planning, there may be alterations to the delineation of tumour volumes when compared to CT alone. For this patient, a geographic miss of tumour would have occurred if CT data alone were used for radiotherapy planning.     

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.