Positron emission tomography in gastric and esophageal cancer

Impact of tumor histology on detection of pelvic and para-aortic nodal metastasis with 18F-fluorodeoxyglucose-positron emission tomography in stage IB cervical cancer

OBJECTIVE

18F-fluorodeoxyglucose-positron emission tomography (FDG-PET) detection of metastatic nodal disease is useful for guiding cervical cancer treatment but the impact of tumor histology is unknown. This study reports the detection of FDG avid pelvic and para-aortic lymph nodes in patients with early stage cervical cancer with squamous carcinoma and adenocarcinoma tumor histology.

METHODS

Patients with International Federation of Gynecology and Obstetrics (FIGO) 2009 stage IB1-2 cervical cancer who underwent pre-surgical FDG-PET between March 1999 and February 2018 were identified in a tertiary academic center database. All patients had radical hysterectomy with pelvic and para-aortic lymph node dissection. Detection of pelvic and para-aortic lymph nodes by FDG-PET versus surgical dissection was compared. FDG-PET sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were determined and stratified by tumor histology.

RESULTS

We identified 212 patients with early stage cervical cancer (84% FIGO IB1, 16% IB2) who underwent pre-surgical FDG-PET; 137 (65%) patients had squamous carcinoma and 75 (35%) patients had adenocarcinoma. PET/computed tomography was performed in 189 (89%) patients and 23 (11%) had PET only. Surgical dissection revealed positive pelvic and para-aortic lymph nodes in 25% and 3.3% of patients, respectively. For squamous carcinoma, sensitivity, specificity, PPV, and NPV of FDG-PET for pelvic nodal metastasis were 44%, 99%, 95%, and 78%, respectively. For adenocarcinoma, the corresponding results for pelvic nodal metastasis were 25%, 99%, 67%, and 92%, respectively. The overall values for sensitivity, specificity, PPV, and NPV of FDG-PET for para-aortic nodal metastasis were 29%, 99%, 67%, and 98%, respectively.

DISCUSSION

Pelvic nodal metastasis was less likely to be detected by FDG-PET in patients with early stage adenocarcinoma than with squamous carcinoma.

The multidisciplinary management of gastrointestinal cancer. Multimodal treatment of gastric cancer

Although radical surgical R0 resections are the basis of cure for gastric cancer, surgery alone only provides long-term survival in 20-30% of patients with advanced-stage disease. Thus, in Western and European countries, advanced gastric cancer has a high risk of recurrence and metachronous metastases. Very recently, multimodal strategies combining different neoadjuvant and/or adjuvant protocols have improved the prognosis of gastric cancer when combined with surgery with curative intent. As used in palliative regimens, the combination of cisplatin with intravenous or oral fluoropyrimidines has been the integral component of such (neo)adjuvant strategies. However, the cytotoxic agents docetaxel, oxaliplatin and irinotecan and new targeted biologicals such as cetuximab, bevacizumab or panitumumab are currently under investigation, with or without irradiation, in multimodal treatment regimens. These studies may further increase R0 resection rates, and prolong disease-free and overall survival times in the treatment of advanced gastric cancer. This article reviews the most relevant literature on multimodal treatment of gastric cancer, and discusses future strategies to improve locoregional failures.

The current status of FDG-PET in tumour volume definition in radiotherapy treatment planning

Positron emission tomography (PET) scan, mainly using 18 F-fluoro-deoxyglucose (FDG) as a tracer, is currently widely accepted as a diagnostic tool in oncology. It may lead to a change in staging and therefore in treatment management. PET can also be used to define the target volume in radiation treatment planning and to evaluate treatment response. In this review, we focused on issues concerning the role of PET in target volume delineation, both for the primary tumour and regional lymph nodes. A literature search was performed using MEDLINE. Furthermore, the following questions were addressed: does PET allow accurate tumour delineation and does it improve the outcome of radiotherapy, in terms of reduced toxicity or a higher tumour control probability? Combined computer tomography (CT) and PET information seems to influence target volume delineation. Using (CT-) PET scan, interobserver variability is being reduced. Only few studies compared delineation based on PET with pathologic examination, showing a complex relation. Preliminary results concerning incorporation of PET information in to target volume delineation varies in different tumour sites. In the field of lung cancer, incorporation of PET seems to improve tumour coverage and spare normal tissues, which may lead to less toxicity or the possibility to escalate dose. In oesophageal cancer and in lymphoma, PET scan can be used to include PET positive lymph nodes in the target volume. In most other tumour sites not enough data are currently available to draw definitive conclusions about the role of PET in radiation treatment planning.

A prospective evaluation of the impact of 18-F-fluoro-deoxy-D-glucose positron emission tomography staging on survival for patients with locally advanced esophageal cancer

PURPOSE

To determine the impact of 18-F-fluoro-deoxy-D-glucose positron emission tomography (FDG-PET) in the staging and prognosis of patients with locally advanced esophageal cancer (LAEC).

METHODS AND MATERIALS

Between January 2000 and October 2004, all patients with LAEC evaluated in the Department of Radiation Oncology were considered for enrollment into a Phase II trial of preoperative chemoradiation. Entry required a staging whole-body FDG-PET scan.

RESULTS

One hundred ten consecutive patients were evaluated; 38 were ineligible for reasons including treatment elsewhere, prior malignancy, or refusal of treatment. After conventional staging (clinical examination, endoscopic ultrasound, and chest/abdominal computerized tomography), 33 patients were ineligible because of metastatic disease or poor performance status. Of the remaining 39 patients, 23 were confirmed to have LAEC after FDG-PET staging and were treated in the Phase II trial (Cohort I). Sixteen patients, however, had FDG-PET findings consistent with occult metastatic disease and were deemed ineligible for the trial but were treated with curative intent (Cohort II). The 2-year survival rate for the 23 patients in Cohort I was 64%, compared with 17% (p=0.003) for patients in Cohort II (FDG-PET positive).

CONCLUSIONS

More than one-third of patients determined to have LAEC with conventional staging were upstaged with the use of FDG-PET. Despite comparable therapy, upstaging with FDG-PET predicts poor 2-year survival.