True statements regarding appendiceal neoplasms include which of the following?

a. Carcinoid tumors of the appendix less than 1.5 cm are adequately treated by simple appendectomy

Carcinoids represent two-thirds of all appendiceal neoplasms. Nearly half of all GI carcinoids arise in the appendix at a mean age of 41 years. Two-thirds of the time the carcinoid is only incidentally detected, only 0.5% have evidence of distant metastatic spread at resection. In one experience, carcinoids between 1.5 and 2.0 cm have had minimal metastatic potential and those smaller than 1.5 cm never metastasized. In the 1% that are larger than 2 cm however, metastases are frequent and 80% recur even after resection at this size. Adenocarcinoma of the appendix is exceedingly rare. These tumors occur in elderly patients at the base of the appendix. Appendicitis often follows and the diagnosis is not made preoperatively and is rarely considered during surgery since the appearance of the tumor may mimic perforated appendicitis. Up to half the patients have metastatic disease at diagnosis and the peritoneum is the most common site of spread. Survival is proportional to tumor stage. Dukes’ Stage A disease may be treated simply with appendectomy if all disease can be removed with reasonable margins. Dukes’ B and C lesions require formal right hemicolectomy for disease control. Survival is, stage for stage, similar to colon cancer after 5 years. Appendiceal adenocarcinomas also appear to have an association with secondary tumors, often of the GI tract, in up to 35% of patients. Patients with mucinous cystadenocarcinoma of the appendix typically are symptomatic, and wide resection of the primary disease, together with debulking of peritoneal implants, is indicated. Indolent progression of metastases commonly results in prolonged survival rates (50% at 5 years) during which patients may require repeated laparatomies for complications of the disease.