Is Peritoneal Tumor Penetration of Prognostic Importance in Gastrointestinal Stromal Tumors?

• Published in: Annals of surgical oncology 2019-12, Vol.26 (13), p.4730-4736
• Main Authors: Hølmebakk, T., Bjerkehagen, B., Lobmaier, I. V. K., Hompland, I., Stoldt, S., Boye, K.
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Aged; Aged, 80 and over; Carcinoma; Esophagus; Female; Follow-Up Studies; Gastric cancer; Gastrointestinal cancer; Gastrointestinal Neoplasms - pathology; Gastrointestinal Neoplasms - surgery; Gastrointestinal Stromal Tumors - pathology; Gastrointestinal Stromal Tumors - surgery; Humans; Imatinib; Male; Medical prognosis; Medicine; Medicine & Public Health; Mesenchyme; Metastases; Middle Aged; Oncology; Peritoneal Neoplasms - secondary; Peritoneal Neoplasms - surgery; Peritoneum; Prognosis; Prospective Studies; Rectum; Retrospective Studies; Risk Factors; Rupture; Sarcoma; Statistical analysis; Surgery; Surgical Oncology; Survival Rate; Tumors; Young Adult
• ISSN: 1068-9265; 1534-4681
• DOI: 10.1245/s10434-019-07813-x

Background Peritoneal tumor penetration (PP) strongly affects prognosis in gastrointestinal carcinomas. In gastrointestinal stromal tumor (GIST), its significance in the absence of tumor rupture has not been subjected to detailed analysis. Methods Patients undergoing complete resection for non-metastatic GIST from 2000 to 2017 were identified in the regional sarcoma database at Oslo University Hospital. Patients with extraperitoneal tumors (esophagus, rectum) or ruptured tumors were excluded from the study. Rupture was defined according to the Oslo criteria, and PP was assessed via routine histopathologic examination by sarcoma pathologists. Results The study enrolled 341 patients. The median follow-up period was 51 months (range 0–175) months. In 82 (24%) of the 341 patients, PP was recorded. There were 32 recurrences, 9 in patients with PP and 23 in patients without PP. Despite statistically significant associations between PP and established risk factors (size, mitotic index, non-gastric location), the 5-year recurrence-free survival rate did not differ between the patients with PP (86%) and those without PP (90%) (hazard ratio 1.25; 95% confidence interval 0.58 – 2.70; P  = 0.577). Adjuvant imatinib was administered to 53 of 97 patients in the high-risk category. The recurrence rates did not differ between the PP-positive and PP-negative patients in either group. Conclusions In GIST, PP without tumor rupture appears not to influence prognosis. This lack of prognostic significance may reflect unexplored differences between epithelial and mesenchymal malignancies.