Pre-Chemoradiotherapy FDG PET/CT cannot Identify Residual Metabolically-Active Volumes within Individual Esophageal Tumors

Objective

To study whether subvolumes with a high pre-chemoradiotherapy (CRT) FDG uptake could identify residual metabolically-active volumes (MAVs) post-CRT within individual esophageal tumors. Accurate identification will allow simultaneous integrated boost to these subvolumes at higher risk to improve clinical outcomes.

Methods

Twenty patients with esophageal cancer were treated with CRT plus surgery and underwent FDG PET/CT scans before and after CRT. The two scans were rigidly registered. Seven MAVs pre-CRT and four MAVs post-CRT within a tumor were defined with various SUV thresholds. The similarity and proximity between the MAVs pre-CRT and post-CRT were quantified with three metrics: fraction of post-CRT MAV included in pre-CRT MAV, volume overlap and centroid distance.

Results

Eight patients had no residual MAV. Six patients had local residual MAV (SUV ≥2.5 post-CRT) within or adjoining the original MAV (SUV ≥2.5 pre-CRT). On average, less than 65% of any post-CRT MAVs was included in any pre-CRT MAVs, with a low volume overlap <45%, and large centroid distance >8.6 mm. In general, subvolumes with higher FDG-uptake pre-CRT or post-CRT had lower volume overlap and larger centroid distance. Six patients had new distant MAVs that were determined to be inflammation from radiation therapy.

Conclusions

Pre-CRT PET/CT cannot reliably identify the residual MAVs within individual esophageal tumors. Simultaneous integrated boost to subvolumes with high FDG uptake pre-CRT may not be feasible.

Benign and solid tumors of the liver: relationship to sex, age, size of tumors, and outcome

From 1983 through 1997, our center diagnosed 130 cases of benign neoplasms: 27 with focal nodular hyperplasia (FNH), 25 with hepatic adenoma, 71 with cavernous hemangioma, and seven with mixed tumors of different diagnoses. Most often these lesions were seen in females [female-to-male ratio (f/m): 5.5/1]. Hepatic adenomas and mixed tumors were seen exclusively in females and FNH predominantly in females (f/m: 26/1). Hemangiomas, however, were not uncommon in men (f/m: 52/19) relative to the other tumors (P < 0.001). Furthermore patients with hemangioma were older (mean age: 49 years) whereas patients with hepatic adenoma, FNH, and mixed tumors were often younger (mean age: 33, 35, and 44 years respectively; P < 0.004). Oral contraceptive steroid use was related by 21 of 25 patients (84%) with hepatic adenoma, 22 of 26 (85%) females with FNH, five of seven (71%) females with mixed tumors, and 10 of 52 (19%) patients with hemangioma. Ninety-five of the 130 patients (73%) had one or more symptoms. There was no statistically significant correlation between symptoms and the size of the lesion, the final diagnosis, and whether there were solitary or multiple masses. Three of 25 (12%) with hepatic adenoma presented with rupture, and one of 27 (4%) with FNH had such a consequence. None of the hemangiomas presented with rupture or progressed to such a state. One patient with hepatic adenoma (4%) had a focus of malignancy. Surgical removal of benign tumors was performed in 82 of 130 patients (63%), and there was one operative mortality (1.2%) in a patient who had a caudate lobe FNH. The types of surgical procedures included segmentectomy (62%), lobectomy (34%), and trisegmentectomy (4%). In two of 84 patients who had undergone laparotomy resection was not technically possible. Resection is recommended in all cases of hepatic adenoma because of fear of rupture or associated focus of malignancy. FNH was not observed to undergo a malignant transformation and will rarely rupture. Surgery is only recommended for symptomatic hemangioma, and size of the lesion is not a criterion for excision.

Experience with staging laparoscopy in pancreatic malignancy

BACKGROUND

The role of diagnostic laparoscopy in the staging of abdominal malignancies is not well defined.

METHODS

We retrospectively reviewed the usefulness of diagnostic laparoscopy as a staging procedure in pancreatic malignancy. This experience between February 1988 and May 1997 involves 109 cases of suspected or proven pancreatic malignancy. All laparoscopies were performed with the patient under conscious sedation and local anesthesia in an endoscopy suite.

RESULTS

Of the 109 patients with pancreatic cancer, 45 (42%) had metastatic disease. The use of computed tomography (CT) alone revealed the existence of liver metastases in 10 of 109 (9%) patients, which were confirmed laparoscopically. The further use of laparoscopy identified metastases in 29 more cases: hepatic, 23; hepatic and peritoneal, 3; peritoneal and mesenteric, 1; and mesenteric, 2. CT in conjunction with laparoscopy therefore revealed metastatic liver, peritoneal, or mesenteric lesions in 39 of 109 (36%) patients with pancreatic cancer. After staging laparoscopy, 67 of 69 patients underwent laparotomy. Metastatic disease was identified at laparotomy in 6 more patients; however, only 4 of these patients had metastases to the liver whereas 2 had metastases to the peripancreatic lymph nodes. Therefore, in patients with pancreatic malignancy, the negative predictive value for the diagnosis of metastases to the liver, peritoneum or mesentery was 94% (61 of 65 patients). The positive predictive value of laparoscopy alone for the detection of metastatic disease to the liver, peritoneum, or mesentery was 88% (29 of 33 patients). Laparoscopy was successfully performed without complications in all patients with pancreatic cancer; however, one had a technically unsatisfactory examination. The overall rate of resectability after staging by imaging studies and laparoscopy was 57% (35 of 61 patients).

CONCLUSIONS

In patients with a negative CT for metastases, laparoscopic identification of metastases avoided unnecessary laparotomy in 29 of 99 (29%) patients with pancreatic cancer. Staging laparoscopy is indicated in all cases of pancreatic malignancy before an attempt at a surgical cure.