Page 34 - New epidemiological and PSMA-expression based paradigms in salivary gland tumors

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Chapter 2
Patient, tumor, and treatment characteristics: Primary SGPAs occurred more often in women (59.5%) than in men (40.5%) (Table 1), showing a female to male ratio of 1.43:1. The mean age at primary diagnosis was 48.0 in men, and 49.6 in women. Seventy-eight patients (2%) were under 18 when diagnosed. Around 40% of cases occurred in the age group of 40-59. In women, a bimodal age distribution was found, with peaks around the ages of 38 and 64 (p<0.0001). Age in men showed a normal distribution (Figure 2).
The most common tumor site by far was the parotid gland (78%), followed by the minor salivary glands (11%) and the submandibular glands (9%). Only six SGPAs occurred in sublingual glands (<1%).
Submandibular SGPA was more common in women than in men, but minor- gland SGPA was more common in men than women (Table 1). In patients under 18, the minor and submandibular glands were affected more often than in adults (Additional Table B).
Surgical technique was reported as partial parotidectomy (35%), local excision (8%) and complete gland removal (6%). In 41% of cases the excerpts did not specify the surgical technique and in 1%, there was no mention of type of procedure at all. Histological margins were negative in 58%, positive in 14%, uncertain in 7%, and not reported in 21%.
Recurrence rates, characteristics, and malignant transformation: The disease recurred in 125 (4.6%) of the 2 719 patients who had at least five years of follow-up. Twenty (16%) also had a second recurrence, and two (10%) had a third. In 4 patients (0.15%), the disease recurred as carcinoma ex pleomorphic adenoma, which means that 3.2% of all recurrences (4/125) showed malignant transformation. First-recurrence rates were 2.3% at five years, 4.0% at 10 years, 5.6% at 15 years, and 6.7% at 20 years of follow-up, with a 7 years’ median time to first recurrence (range 0.6-20.7, 95% CI 5.9-8.1) (Figure 3). Second-recurrence rates were 12% at five years and 14% at ten years of follow-up. The median time to second recurrence was 2 years (95% CI: 0.9-3.1). Sex distribution patterns were similar in both recurrences and primary tumors (58% females versus 42% males). The mean age at primary diagnosis was 40 in patients who later developed