Impact of histopathological risk factors on the treatment of stage ib-iib uterine cervical cancer

In the past decade, the incidence of adenocarcinoma of the uterine cervix gradually increased. Recent literature revealed that the molecular pathogenesis differs by histological subtype, and the histological subtype should be considered in deciding treatments for patients with uterine cervical cancer. However, no treatment based on histological type or genomic signature has been recommended in various treatment guidelines. The Japanese treatment guidelines recommend either radical hysterectomy or definitive radiotherapy as primary treatment for patients with stage IB-IIB squamous cell carcinoma and a radical hysterectomy-based approach for those with non-squamous cell carcinoma because of its lower radiosensitivity. The impact of histological type on survival outcome of uterine cervical cancer is controversial. Our retrospective studies suggested that the difference in survival outcome by histological subtype might be remarkable with disease progression. Recent literature suggested that usual-type endocervical adenocarcinoma, which is the most common histological type of cervical adenocarcinoma, showed a similar survival outcome to squamous cell carcinoma. In contrast, gastric-type mucinous carcinoma of the uterine cervix, which has aggressive clinical behavior and is not associated with high-risk human papillomavirus infection, showed resistance to chemotherapy and radiotherapy. Importantly, gastric-type mucinous carcinoma is rather common in Japan, compared with Western countries. It is therefore conceivable that the survival outcome of non-squamous cell carcinoma may be affected by regional difference in the frequency of gastric-type mucinous carcinoma. A molecular target to refractory uterine cervical cancer, such as gastric-type mucinous carcinoma of uterine cervix, still remains to be identified.