Larger early-stage tumors (IB2 and IIA more than 4 cm) may be treated with radiation therapy and cisplatin-based chemotherapy, hysterectomy (which then usually requires adjuvant radiation therapy), or cisplatin chemotherapy followed by hysterectomy. When cisplatin is present, it is thought to be the most active single agent in periodic diseases. Such addition of platinum-based chemotherapy to chemoradiation seems not only to improve survival but also reduces risk of recurrence in women with early stage cervical cancer (IA2-IIA). A Cochrane review found a lack of evidence on the benefits and harms of primary hysterectomy compared to primary chemoradiotherapy for cervical cancer in stage IB2.