Early prediction of treatment response to high-dose salvage chemotherapy in patients with relapsed germ cell cancer using [(18)F]FDG PET

To assess the ability of [(18)F]fluorodeoxyglucose positron emission tomography for the early prediction of response in patients with relapsed metastatic germ cell tumours undergoing salvage high-dose chemotherapy. The role of positron emission tomography was compared with established means of tumour response assessment such as CT scans/MRI and serum tumour marker changes. In addition, positron emission tomography was compared with a current prognostic score which differentiates three prognostic groups with failure-free survival rates ranging from 5-50%. [(18)F]fluorodeoxyglucose uptake of metastases from germ cell tumours as well as CT scans and serum tumour marker were acquired after 2-3 cycles of induction chemotherapy but before the start of high-dose chemotherapy and CT scans/serum tumour marker were compared with the baseline examinations in 23 patients with relapsed germ cell tumours. To evaluate the validity of early response prediction by positron emission tomography, radiological monitoring and serum tumour marker decline, histopathologic response after resection of residual masses and/or the clinical course over 6 months after the end of treatment (relapse vs freedom of progression) were used. Overall, 10 patients (43%) achieved a marker-negative partial remission, three (13%) a marker-positive partial remission, five (22%) a disease stabilization and five (22%) progressed during treatment. Nine patients (39%) remained progression-free over 6 months following treatment, whereas 14 (61%) progressed. The outcome of high-dose chemotherapy was correctly predicted by positron emission tomography/CT scan/serum tumour marker in 91/59/48%. Eight patients with a favourably predicted outcome by CT scans plus serum tumour marker but a positive positron emission tomography prior to high-dose chemotherapy, failed treatment. This results in the following sensitivities/specificities for the prediction of failure of high-dose chemotherapy: positron emission tomography 100/78%; radiological monitoring 43/78%; serum tumour marker 15/100%. The positive and negative predictive values of positron emission tomography were 88 and 100%, respectively. As compared with the prognostic score, positron emission tomography was correctly positive in all patients of the three risk groups who failed treatment. In addition, a negative positron emission tomography correctly predicted a favourable outcome in the good and intermediate group. [(18)F]fluorodeoxyglucose positron emission tomography imaging can be used to assess response to chemotherapy in patients with relapsed germ cell tumours early in the course of treatment and may help to identify patients most likely to achieve a favourable response to subsequent high-dose chemotherapy. In patients with response to induction chemotherapy according to CT scans or serum tumour marker evaluation, positron emission tomography seems to add information to detect patients with an overall unfavourable outcome. It may also be a valuable addition to the prognostic model particularly in the good and intermediate group for further selection of patients who will profit from high-dose chemotherapy.     

Management of Early-stage Hodgkin Lymphoma: A Practice Guideline

In the past, treatment for patients with early-stage Hodgkin lymphoma consisted mainly of radiotherapy. Now, chemotherapy alone and chemoradiotherapy are treatment options. These guidelines aim to provide recommendations on the optimal management of early-stage Hodgkin lymphoma. We conducted a systematic review searching MEDLINE, EMBASE, the Cochrane Library and other literature sources from 2003 to 2015, and applied the Grading of Recommendations Assessment, Development and Evaluation (GRADE). Two authors independently reviewed and selected studies, and appraised the evidence quality. The document underwent internal and external review by content, methodology experts, a patient representative and clinicians in Ontario. We have issued recommendations for patients with classical Hodgkin lymphoma and with nodular lymphocyte predominant Hodgkin lymphoma; with favourable and unfavourable prognosis; and for the use of positron emission tomography to direct treatment. We have provided our interpretation of the evidence and considerations for implementation. Examples of recommendations are: ‘Patients with early-stage classical Hodgkin lymphoma should not be treated with radiotherapy alone’; ‘chemotherapy plus radiotherapy or chemotherapy alone are recommended treatment options for patients with early-stage non-bulky Hodgkin lymphoma’; ‘The Working Group does not recommend the use of a negative interim positron emission tomography scan alone to identify patients with early-stage Hodgkin lymphoma for whom radiotherapy can be omitted without a reduction in progression-free survival’. Through the use of GRADE, recommendations were geared towards patient important outcomes and their strength reflected the available evidence and its interpretation from the patients’ point of view.     

Do we need an early unfavorable (intermediate) stage of Hodgkin's lymphoma?

The outcome of patients who have early unfavorable or intermediate-stage Hodgkin's lymphoma has greatly improved. The increasing efficacy of chemotherapy and late toxic effects of wide-field radiotherapy justify the careful testing of the new involved-node radiotherapy principle in the combined-modality approach. For the purpose of tailoring treatment to the individual patient we need more accurate measures, preferably predictive factors that may tell us how the individual patient should be treated. The result of an early positron emission tomography scan with fluorodeoxyglucose may well become the major new treatment-related guidance for an individually tailored treatment approach.     

Late clinically silent perforation of intestinal non-Hodgkin's lymphoma

The combined positron emission tomography/computed tomography scan is ideal in the initial staging of lymphomas and for evaluating the response to treatment. In posttreatment studies, the presence of a residual, metabolically active mass at the site of initially documented lymphoma is not expected to be anything other than residual active disease. We describe a case of intestinal non-Hodgkin's lymphoma that responded to chemotherapy but with a residual metabolically active mass at the site of initial disease. This mass was revealed to be a clinically silent closed intestinal perforation with abscess formation. Similar conditions should be kept in mind during the interpretation of posttreatment combined positron emission tomography/computed tomography scan and before exposing the patient to additional chemotherapy.     

PET scan-positive cat scratch disease in a patient with T cell lymphoblastic lymphoma

In patients who have history of lymphoma, a positive positron emission tomography (PET) scan is frequently considered as good evidence for relapse and/or persistent disease. Thus, lymph node biopsy is not always done to confirm the diagnosis of relapse or refractory lymphoma before a patient is subjected to further chemotherapy. We report a case of patient with history of T cell lymphoblastic lymphoma who presented again with inguinal lymphadenopathy and positive study on positron emission tomography suggestive of lymphoma relapse. This was pathologically proven to be cat scratch disease. This case suggests that in the immunocompromised patients who had history of lymphoma, infectious etiology should be ruled out for PET scan-positive lymphadenopathy.     

FDG PET and high-dose therapy for aggressive lymphomas: toward a risk-adapted strategy

PURPOSE OF REVIEW: Functional metabolic imaging through fluorine-18 fluorodeoxyglucose positron emission tomography has recently come to the forefront in the management of various solid and hematologic malignancies. This review summarizes the developments in risk assessment through positron emission tomography in patients with lymphoma and the implications for management. RECENT FINDINGS: In addition to improving staging and response assessment, positron emission tomography has emerged as a strong prognostic tool in patients with aggressive lymphomas. A positron emission tomographic scan performed after only a few cycles of chemotherapy can accurately predict relapse risk, and most studied patients with abnormal positron emission tomographic scans have had distinctly poorer clinical outcomes than patients with negative scans. SUMMARY: With confirmation of these findings, a more individualized, risk-adapted approach to the treatment of aggressive lymphomas will be feasible. Early identification of high-risk patients through the combination of positron emission tomography and existing prognostic indices could lead to earlier implementation of intensive therapies and improved clinical outcomes.     

Locally advanced esophageal cancer

Opinion statement Patients diagnosed with adenocarcinoma or squamous cell carcinoma of the esophagus should undergo computed tomography of the chest and abdomen and positron emission tomography to look for evidence of distant metastatic disease. In the absence of systemic metastases, locoregional staging should be performed with endoscopic ultrasonography and fine needle aspiration of accessible periesophageal lymph nodes and any detectable celiac lymph nodes. Patients found to have T3 tumors (transmural extension), T4 tumors (invasion of adjacent structures), or N1-M1a (lymph nodepositive) disease do poorly when treated with surgery alone; 5-year survival is less than 20%. These patients should be considered for combined modality therapy. Patients with T4 disease are generally not deemed candidates for surgical resection; they may be considered for definitive chemoradiotherapy. Patients with T3 disease or lymph node-positive disease may be treated with neoadjuvant chemoradiotherapy followed by surgery or definitive chemoradiotherapy alone. Patients considered for trimodality therapy should be fully restaged before surgery to assess their response to neoadjuvant treatment. This should include repeat endoscopic ultrasound and fine needle aspiration of lymph nodes. Patients whose lymph node metastases do not completely respond to neoadjuvant therapy are unlikely to benefit from the addition of surgery. Patients with persistently positive celiac lymph nodes have a very poor prognosis and should not undergo surgery. Patients with persistent nodal disease who have good performance status may be considered for additional chemotherapy. Patients with locally advanced esophageal cancer who have poor performance status are not good candidates for combined modality therapy. These individuals are best managed with palliative intent. Particular attention should be given to alleviating the common problem of dysphagia, which causes significant morbidity.     

Mediastinal staging 2005: pictures, scopes, and scalpels

Staging of the mediastinum for lung cancer has matured dramatically with the advent of newer technologies in imaging and endoscopic surveillance. Some of these technologies such as positron emission tomography (PET) scanning are becoming mainstream in the evaluation of patients with clinically suspicious mediastinal disease as seen on computed tomography (CT), while others such as endobronchial ultrasound are reserved for specialty expertise and await validation. While much improvement has been made in the accurate preoperative staging of patients having surgery as the primary modality in lung cancer, controversy exists regarding the restaging of locally advanced cases after induction chemotherapy or chemoradiotherapy. A major concentration on these restaging issues is warranted since it is now generally agreed that sterilization of the mediastinum after induction therapy has an impact on the prognosis of patients with stage IIIA disease, and accurate staging after therapy may rationally guide diverse therapeutic interventions in these patients.     

A case of effective neoadjuvant chemoradiotherapy with capecitabine for locally advanced sigmoid colon cancer

A 60-year-old man was hospitalized for urodynia. Clinical examinations demonstrated a locally advanced sigmoid colon cancer with direct extension to the bladder, rectum, and pelvic wall. We considered that curative resection was not possible and performed temporary colostomy for fecal diversion. After colostomy, he was treated with neoadjuvant chemoradiotherapy(NACRT)for down staging. The radiation therapy was delivered with 45 Gy(1. 8 Gy/fraction; 5 days/week×5 weeks), and the concurrent chemotherapy was performed with capecitabine(825mg/m2 twice daily on radiotherapy days). CT scan confirmed a dramatic response with downstaging of the tumor following NA-CRT(clinical response, PR in the RECIST criteria). Invasion of the tumor to pelvic wall disappeared on CT scan, and[18F]fluorodeoxyglucose positron emission tomography( FDG-PET)failed to demonstrate any distant metastasis. We considered that the tumor was hence resectable and performed total pelvic exenteration(TPE)1 month after NACRT. A pathological examination of surgical specimens confirmed a R0 resection. The patient made an unremarkable postoperative recovery. He went on to receive adjuvant capecitabine chemotherapy, completing four cycles. He remains well and disease-free 10 months following surgery. NACRT with capecitabine appears effective even for unresectable locally advanced sigmoid colon cancer.     

Correlation of molecular response as measured by 18-FDG positron emission tomography with outcome after chemoradiotherapy in patients with esophageal carcinoma

PURPOSE: To determine whether 18-fluorodeoxyglucose positron emission tomography (PET) computed tomography scans predict the pathologic complete response and disease-free and overall survival in patients with esophageal carcinoma undergoing definitive or preoperative chemoradiotherapy. METHODS AND MATERIALS: The records of patients with esophageal carcinoma presenting for definitive or preoperative treatment and undergoing pre- and post-treatment 18-fluorodeoxyglucose PET-computed tomography scans were retrospectively reviewed. The histologic type, T stage, and nodal status were the variables investigated to determine a relationship with the baseline standardized uptake value (SUV) of the primary tumor at diagnosis. We also attempted to determine whether a relationship exists between the percent decrease in SUV and a pathologic complete response, overall and disease-free survival. RESULTS: A total of 81 patients, 14 women and 67 men, underwent 18-fluorodeoxyglucose PET-computed tomography scanning before treatment and 63 also had post-treatment scans. T stage and tumor location predicted in univariate, but not multivariate, analysis for the initial SUV. Of the patients with a postchemoradiotherapy SUV of <2.5, 66% had tumor in the surgical specimen and 64% of patients had positive lymph nodes at surgery that were not imaged on the postchemoradiotherapy PET scan. A trend existed for post-treatment SUV and the days from radiotherapy to surgery to predict for a pathologic complete response (p = 0.09 and p = 0.08, respectively). The post-treatment SUV predicted for disease-free survival in the definitive chemoradiotherapy group (p = 0.01). CONCLUSIONS: A correlation was found between the depth of tumor invasion and the baseline SUV. The post-treatment SUV predicted for disease-free survival in the definitive chemoradiotherapy group. Caution should be exercised in using post-treatment PET scans to determine the necessity for surgical resection.     

Positron emission tomography imaging for lymphoma

PURPOSE OF REVIEW: To review the current role and the limitations of F-fluorodeoxygenase positron emission tomography in the management of lymphoma, with a particular focus on studies published since January 2004. RECENT FINDINGS: F-fluorodeoxygenase positron emission tomography should be routinely performed at the initial diagnosis of patients with suffering from Hodgkin's disease because it adds useful informations to conventional staging techniques. Residual F-fluorodeoxygenase uptake is an important prognostic factor after one or a few cycles of chemotherapy, but it is clearly too early to change patient treatment on the basis of F-fluorodeoxygenase positron emission tomography results. F-fluorodeoxygenase positron emission tomography is the best noninvasive imaging technique after treatment; however, it is always indicated to correlate positron emission tomography findings with clinical data, other imaging modalities, a biopsy, or all three to reduce the risk of false positive results. There are some concerns about the positive predictive value of positron emission tomography after treatment, especially in childhood lymphoma. Clinicians should be aware of positron emission tomography findings in specific clinical conditions in this patient population. F-fluorodeoxygenase positron emission tomography combined with computed tomography offers advantages over the two used separately and read side by side. It may be particularly useful for the planning of radiation therapy or for the planning of a surgical biopsy. Several studies have shown that F-fluorodeoxygenase positron emission tomography is definitively superior to Ga scintigraphy. New radiotracers such as F-fluorothymidine may be useful for the noninvasive assessment of proliferation in vivo. SUMMARY: F-fluorodeoxygenase positron emission tomography has become the most important nuclear medicine imaging modality in the field of lymphoma. It should be routinely used in the treatment of lymphoma patients.     

Intensified Neoadjuvant Chemotherapy with Nab-Paclitaxel plus Gemcitabine Followed by FOLFIRINOX in a Patient with Locally Advanced Unresectable Pancreatic Cancer

The prognosis of patients with locally advanced pancreatic cancer can be improved if secondary complete (R0) resection is possible. In patients initially staged as unresectable this may be achieved with neoadjuvant treatment which is usually chemoradiotherapy based. We report the case of a 46-year-old patient with an unresectable, locally advanced pancreatic cancer (pT4 Nx cM0 G2) who was treated with a sequential neoadjuvant chemotherapy regimen consisting of 2 cycles of nab-paclitaxel plus gemcitabine followed by 4 cycles of FOLFIRINOX. Neoadjuvant chemotherapy resulted in secondary resectability (R0 resection). After 2 cycles of nab-paclitaxel plus gemcitabine, the patient already had a complete metabolic remission as measured by integrated fludeoxyglucose (¹⁸F) positron emission tomography and computerized tomography. After a follow-up of 18 months the patient is alive without progression of disease. We propose to assess the clinical benefit of sequencing the combinations nab-paclitaxel plus gemcitabine and FOLFIRINOX as neoadjuvant therapy for patients with locally advanced and initially unresectable pancreatic cancer in a controlled clinical trial.Key Words: Pancreatic cancer, Locally advanced disease, Neoadjuvant chemotherapy, Nab-paclitaxel, Gemcitabine, 5-Fluorouracil, Folinic acid, Oxaliplatin, Irinotecan     

Cetuximab in the management of locoregionally advanced head and neck cancer: Expanding the treatment options?

The treatment of locoregionally advanced squamous cell carcinoma of the head and neck (SCCHN) has evolved in recent years as a consequence of a better understanding of the potential benefits associated with altered radiation fractionation regimens, concurrently administered chemotherapy and radiotherapy (chemoradiotherapy) and induction chemotherapy. Concurrent chemoradiotherapy is a treatment option for technically resectable disease, where functional morbidity precludes the use of surgery. Induction chemotherapy followed by radiotherapy may also be used in this setting, and has been validated for larynx preservation. Concurrent chemoradiotherapy is a standard treatment approach for medically fit patients with locoregionally advanced unresectable disease. However, the toxicity burden of additional chemotherapy in both the concurrent chemoradiotherapy and induction chemotherapy settings can have implications for treatment compliance and may impede the administration of chemotherapy and/or radiotherapy to schedule. The epidermal growth factor receptor (EGFR)-targeted IgG1 monoclonal antibody, cetuximab (Erbitux®), has shown significant clinical benefits in the treatment of both locoregionally advanced and recurrent and/or metastatic SCCHN. A phase III study in locoregionally advanced disease demonstrated significant improvements in locoregional control and progression-free and overall survival with cetuximab plus radiotherapy compared with radiotherapy alone, and overall survival benefits were maintained at 5 years. The addition of cetuximab to concurrent chemoradiotherapy has been shown to be feasible in phase II trials and is being investigated in phase III trials. Preliminary evidence suggests that cetuximab could be incorporated into induction management strategies. Taken together, these data support an important role for cetuximab in the treatment paradigm for locoregionally advanced SCCHN.     

F-18 fluorodeoxy-D-glucose positron emission tomography scan in the initial evaluation of patients with a primary melanoma thicker than 4 mm

Metabolic imaging with F-18 fluorodeoxy-D-glucose positron emission tomography is one of the most sensitive and non-invasive techniques, and has proved useful in melanoma. We designed, in 2004, at the Institute Gustave Roussy, a prospective study to determine the value of F-18 fluorodeoxy-D-glucose positron emission tomography scanning in the detection of regional and/or distant metastasis in 25 new patients referred for the treatment of a primary melanoma thicker than 4 mm (tumor node metastases stage T4). The sentinel lymph node biopsy was proposed for all the patients without a palpable regional lymph node. Abnormal positron emission tomography scan findings were correlated to available histological data and to the course of the disease. The F-18 fluorodeoxy-D-glucose positron emission tomography scan identified 0/2 intact primary melanomas, 1/4 residual primary melanomas after limited excision, 0/6 lymph node basins with micrometastasis, 4/4 lymph node basins with enlarged palpable lymph nodes and 0 distant metastasis. The sensitivity and specificity of positron emission tomography scans for microscopic lymph node disease in basins were, respectively, 0 and 92%. A false-positive F-18 fluorodeoxy-D-glucose positron emission tomography result in a cervical basin led to a useless cervical lymph node dissection. In three patients, the positron emission tomography scan was positive in distant sites but none of these foci represented a true metastasis.In conclusion, it is not useful to include a positron emission tomography scan in the initial work-up of patients with primary melanoma, even in patients with thick primary melanomas (>4 mm). Sentinel lymph node biopsy remains the technique of choice for the most accurate initial staging.     

Positron emission tomography in gastric and esophageal cancer

PURPOSE OF REVIEW: Positron emission tomography using the positron emitting glucose analogue 18F-fluorodeoxyglucose has recently emerged as a promising metabolism-based whole-body imaging tool for cancer diagnosis and follow-up. Several reports have recently appeared indicating the potential and limitations of this technique. The review limits its scope to the recent advances of 18F-fluorodeoxyglucose positron emission tomography in the clinical management of gastric and esophageal cancer. RECENT FINDINGS: New studies have been reported on the use of 18F-fluorodeoxyglucose positron emission tomography to assess the early and late metabolic response of a gastroesophageal tumor to chemo(radiation) therapy. The metabolic response as measured by serial 18F-fluorodeoxyglucose positron emission tomography, performed before and during treatment or some weeks thereafter, can be used to predict the clinical and histopathologic response. Moreover, the metabolic positron emission tomography response seems to be related to overall and disease-free survival. SUMMARY: Gastroesophageal 18F-fluorodeoxyglucose positron emission tomography could add significant diagnostic information to the different phases of patient management. At initial diagnosis of esophageal cancer, positron emission tomography detects more distant lymph node and organ metastases compared with conventional diagnostics, allowing a more accurate selection of the most appropriate treatment. Serial 18F-fluorodeoxyglucose positron emission tomography performed before and during chemotherapy allows early identification of nonresponding tumors. 18F-fluorodeoxyglucose positron emission tomography performed after a treatment allows accurate assessment of the residual tumor load. 18F-fluorodeoxyglucose positron emission tomography allows accurate detection and restaging of recurrent disease.     

Response assessment by combined PET–CT scan versus CT scan alone using RECIST in patients with locally advanced head and neck cancer treated with chemoradiotherapy

PurposeRECIST have limitations when applied to potentially curable locally advanced squamous cell carcinoma of the head and neck (SCCHN). [¹⁸F]fluorodeoxyglucose–positron emission tomography (PET) scan may be useful in assessing treatment response and predicting patient outcome.Patients and methodsWe studied patients with previously untreated stages III–IVb SCCHN treated with primary concurrent chemoradiotherapy on five prospective clinical trials. Response was assessed by clinical exam, computed tomography (CT), and PET portions of combined PET–CT scan ∼8 weeks after completion of chemoradiotherapy.ResultsFifty-three patients were analyzed. Complete response (CR) was demonstrated in 42 patients (79%) by clinical exam, 15 (28%) by CT, and 27 (51%) by PET. CR as assessed by PET, but not as assessed by clinical exam or CT using RECIST, correlated significantly with progression-free status (PFS) (P < 0.0001). The 2-year PFS for patients with CR and without CR by PET was 93% and 48%, respectively (P = 0.0002).ConclusionsA negative PET scan on combined PET–CT after chemoradiotherapy is a powerful predictor of outcome in patients receiving curative chemoradiotherapy for SCCHN. PET–CT is indicated for response evaluation in this setting to improve the accuracy of post-treatment assessment by CT.     

Occult small cell lung cancer associated with paraneoplastic neurologic syndrome: case report

Cancer is often associated with paraneoplastic syndromes, which may be misinterpreted. We report a case of a patient with occult small cell lung cancer that was initially compounded by clinical features of a paraneoplastic neurologic syndrome. The presence of antineuronal antibodies and positron emission tomography scan guided the search for the underlying tumor. Following chemo-radiotherapy the patient showed no evidence of disease for the next 18 months, whereas only a slight improvement in the neurologic disorders was observed. The course of the small cell lung cancer was very indolent and the paraneoplastic neurologic syndrome did not worsen with the use of cisplatin.     

Treatment of early-stage nonbulky Hodgkin lymphoma

PURPOSE OF REVIEW: Excellent results have been achieved in the treatment of early-stage Hodgkin lymphoma for more than 30 years with radiation therapy alone or the combined modalities of radiotherapy and chemotherapy. A major concern has been the long-term toxicity of treatment, most of which is attributable to radiotherapy. Recent trials that attempt to decrease acute and long-term toxicity are reviewed. RECENT FINDINGS: To address the problem of late treatment morbidity, randomized trials of combined-modality therapy have been conducted demonstrating that the number of chemotherapy cycles and the extent and doses of radiotherapy can be reduced. Several studies, including three randomized trials of chemotherapy alone vs. combined-modality therapy, suggest that chemotherapy alone is a reasonable option for the treatment of nonbulky early-stage Hodgkin lymphoma. Positron emission tomography after one or two cycles of chemotherapy has been found to be highly predictive of treatment outcome for Hodgkin lymphoma. Combination chemotherapy alone including gemcitabine, a highly active drug with a favorable toxicity profile, with positron emission tomography early during treatment is under evaluation. SUMMARY: Less toxic regimens with the aid of positron emission tomography may reduce the short-term and long-term toxicities of treatment of early-stage nonbulky Hodgkin lymphoma.     

Benefits of positron emission tomography scans for the evaluation of radiotherapy

The assessment of tumour response during and after radiotherapy determines the subsequent management of patients (adaptation of treatment plan, monitoring, adjuvant treatment, rescue treatment or palliative care). In addition to its role in extension assessment and therapeutic planning, positron emission tomography combined with computed tomography provides useful functional information for the evaluation of tumour response. The objective of this article is to review published data on positron emission tomography combined with computed tomography as a tool for evaluating external radiotherapy for cancers. Data on positron emission tomography combined with computed tomography scans acquired at different times (during, after initial and after definitive [chemo-]radiotherapy, during post-treatment follow-up) in solid tumours (lung, head and neck, cervix, oesophagus, prostate and rectum) were collected and analysed. Recent recommendations of the National Comprehensive Cancer Network are also reported. Positron emission tomography combined with computed tomography with (¹⁸F)-labelled fluorodeoxyglucose has a well-established role in clinical routine after chemoradiotherapy for locally advanced head and neck cancers, particularly to limit the number of neck lymph node dissection. This imaging modality also has a place for the evaluation of initial chemoradiotherapy of oesophageal cancer, including the detection of distant metastases, and for the post-therapeutic evaluation of cervical cancer. Several radiotracers for positron emission tomography combined with computed tomography, such as choline, are also recommended for patients with prostate cancer with biochemical failure. (¹⁸F)-fluorodeoxyglucose positron emission tomography combined with computed tomography is optional in many other circumstances and its clinical benefits, possibly in combination with MRI, to assess response to radiotherapy remain a very active area of research.     

Imaging of esophageal and gastric cancer

The three major aims of imaging in esophageal and gastric cancer are to distinguish between locoregional and systemic disease (M stage), to determine local tumor extension (T and N stages), and to assess response to chemotherapy or chemoradiotherapy. Depending on the applied standard of reference, the sensitivity of computed tomography (CT) for detection of distant metastases ranges between less than 50% to greater than 90%. In esophageal cancer, positron emission tomography with the glucose analog fluorodeoxyglucose (FDG-PET) has been shown to detect metastatic disease in approximately 20% of the patients who were considered to have only locoregional disease with CT. In clinical studies, endoscopic ultrasound (EUS) has been shown to differentiate between tumor stages T1/T2 and stages T3/T4 with an accuracy of more than 90%. Accuracy of EUS for differentiating individual tumor stages in routine clinical use has been reported to be markedly lower. Assessment of tumor response by FDG-PET has been shown to correlate with histopathologic tumor regression and patient survival. Furthermore, quantitative measurements of tumor FDG uptake may predict histopathologic tumor response and patient outcome as early as 2 weeks after initiation of preoperative chemotherapy.