Aim: To comprehensively review all known reported cases of stomal metastases after percutaneous endoscopic gastrostomy (PEG) to systematically identify risk factors for this complication and to develop strategies for reducing this risk.
Methods: Reported cases were identified by computerized literature searches. Criteria for risk factors for stomal metastases included: a substantially higher relative rate of this factor in patients with stomal metastases than expected from pharyngoesophageal malignancy in general, and biologic plausibility of this phenomenon.
Literature review: Review of all 44 known stomal metastases revealed the following. The mean patient age was 59.0+/-10.0 (SD) yr, and 79% of patients were male. Pathologically proven stomal metastases were located in the abdominal wall (PEG exit site) in 63%, in the gastric wall (PEG entrance site) in 7%, and in both walls in 30%. Mean survival after diagnosis was only 4.3+/-3.8 months. Pathologic risk factors for stomal metastases included: (a) pharyngoesophageal location of primary cancer (in 100% of cases, 0% other locations); (b) squamous cell histology (in 98%, adenocarcinoma in 2%); (c) poorly or moderately differentiated histology (in 92%, well differentiated in 8%); (d) advanced pathologic stage (in 97%, early stage in 3%); and (e) large primary cancer size at diagnosis (mean diameter 4.2+/-2.3 cm). These risk factors appeared to be quantitatively large (e.g., 98% of cases had squamous histology vs 50% expected rate, odds ratio 40.1, OR CI 6.31-246.4, P<0.0001). Therapeutic risk factors for stomal metastases included: (a) endoscopic PEG placement (in 98%, surgical gastrostomy in 2%); (b) pull-string PEG technique (in 98%, push-guidewire in 2%, direct-introducer in 0%); (c) primary cancer untreated or known local recurrence after treatment before PEG (in 87%); and (d) time>or=3 months after PEG insertion (in 100%, <3 months in 0%; mean interval 7.8+/-5.2 months after PEG). Four of the currently reported risk factors are novel (pathologic factors d,e; therapeutic factors a,d).
Conclusions: Strong risk factors for stomal metastases include: pharyngoesophageal primary cancer, squamous cell histology, less well-differentiated cancer, large size, and advanced cancer stage. The risk may be reduced in patients with risk factors by radiotherapy, chemotherapy, or cancer surgery before PEG; by substituting the push-guidewire for the pull-string technique for PEG; and possibly by use of a sheath with the pull-string technique.