Final answer:
The best management step for a 42-year-old woman with stage IV endometriosis, who does not desire fertility and has not responded to conservative treatments, is a hysterectomy with bilateral salpingo-oophorectomy.
Step-by-step explanation:
The patient with stage IV endometriosis experiencing chronic pelvic pain, dyspareunia, and non-responsiveness to hormonal therapies is currently seeking a definitive treatment, and does not desire fertility. The next best step in the management of this patient, considering her age, symptoms, failed medical management, and lack of desire for fertility, would be a hysterectomy with bilateral salpingo-oophorectomy (presuming no contraindications to surgery). This procedure involves the removal of the uterus, cervix, and both ovaries and fallopian tubes, which would likely provide relief from her symptoms and prevent recurrence of endometriosis.
Laparoscopy with excision of endometriosis might be another option if fertility was a concern, or to confirm the diagnosis and extent of disease, but since definitive treatment is sought and fertility is not a concern, more aggressive surgical management is reasonable.