Occult pleural involvement in stage III ovarian carcinoma: role of diaphragm resection.

In a 2-year period 12 diaphragmatic resections were performed on 11 patients with invasive metastases from ovarian carcinoma without significant complications, via transabdominal approach in 10 instances and thoracoabdominal incision in 1. Full-thickness penetration of the diaphragm by tumor occurred in all instances without prior evidence of pleural involvement (occult Stage IV). Six patients had primary disease (Group A) and 5 had recurrent disease (Group B). Ten patients who underwent excision of nonpenetrating diaphragmatic metastases were analyzed for comparison (Group C). Mean diameters of the metastases were as follows: Group A, 7.84 +/- 1.60 cm; Group B, 7.00 +/- 2.24 cm; Group C, 2.51 +/- 1.08 cm. The difference in mean diameter between the penetrating (Groups A and B) and nonpenetrating (Group C) tumors was highly significant (P less than 0.01). Penetrating tumors were 5.0 cm or greater; nonpenetrating tumors were 4.0 cm or less. Invasiveness of diaphragmatic metastases was inversely related to survival in patients with primary but not recurrent disease. Group A patients had a marked survival disadvantage (median survival time of 8 months; range 7-25 months) compared to Group C (median survival time of 26 months; range 13-96+ months; P less than .05). In contrast, Group B patients appeared to gain salutory palliation despite large diaphragmatic masses involving the pleural surface (4/5 alive at 16(+)-33+ months following surgery). Previous reports of response and survival in patients with Stage III Ovarian cancer may have included patients with "occult Stage IV" disease.