Radiotherapy for HPV-related cancers: prediction of therapeutic effects based on the mechanism of tumor immunity and the application of immunoradiotherapy

The current state and future perspectives of radiotherapy for cervical cancer

Radiotherapy is an effective treatment method for cervical cancer and is typically administered as external beam radiotherapy followed by intracavitary brachytherapy. In Japan, center shielding is used in external beam radiotherapy to shorten treatment time and reduce the doses delivered to the rectum or bladder. However, it has several challenges, such as uncertainties in calculating the cumulative dose. Recently, external beam radiotherapy has been increasingly performed with intensity-modulated radiotherapy, which reduces doses to the rectum or bladder without center shielding. In highly conformal radiotherapy, uncertainties in treatment delivery, such as inter-fractional anatomical structure movements, affect treatment outcomes; therefore, image-guided radiotherapy is essential for appropriate and safe performance. Regarding intracavitary brachytherapy, the use of magnetic resonance imaging-based image-guided adaptive brachytherapy is becoming increasingly widespread because it allows dose escalation to the tumor and accurately evaluates the dose delivered to the surrounding normal organs. According to current evidence, a minimal dose of D90% of the high-risk clinical target volume is significantly relevant to local control. Further improvements in target coverage have been achieved with combined interstitial and intracavity brachytherapy for massive tumors with extensive parametrical involvement. Introducing artificial intelligence will enable faster and more accurate generation of brachytherapy plans. Charged-particle therapies have biological and dosimetric advantages, and current evidence has proven their effectiveness and safety in cervical cancer treatment. Recently, radiotherapy-related technologies have advanced dramatically. This review provides an overview of technological innovations and future perspectives in radiotherapy for cervical cancer.

Human papillomavirus independent status on pathologic response and outcomes in locally advanced cervical cancer managed with chemoradiotherapy followed by surgery

OBJECTIVE

While human papillomavirus (HPV) has been shown to play a significant role in cervical cancer carcinogenesis (HPV associated cases), a considerable percentage of cervical cancers occur independently of HPV status (HPV independent).

METHODS

In this retrospective study of 254 locally advanced cervical cancer patients treated with chemoradiotherapy and radical surgery, HPV genotypes were determined using the Anyplex II HPV28 kit that uses multiplex, real time polymerase chain reaction technology. The primary endpoints of this study were to evaluate the complete response to chemoradiotherapy (pathologic complete response), the presence of microscopic (<3 mm, pathologic micro partial response, group 1) and macroscopic (>3 mm, pathologic macro partial response, group 2) residual carcinoma in the cervix, and the persistence of metastatic lymph nodes (group 3) in HPV independent cervical cancers. Secondary endpoints were evaluation of disease-free survival and overall survival.

RESULTS

Of 254 patients studied, 21 cases (8.3%) of cervical cancer were determined to be HPV independent. The percentage of pathologic complete response was found to be higher in the HPV associated group compared with the HPV independent group (p<0.001). In the HPV associated cervical cancer group, 5 year disease free survival was found to be 80.8% versus 59.9% in the HPV independent group (p=0.014). Overall survival was also higher in the HPV associated group (87.9%) compared with the HPV independent patients (69.4%) (p=0.023). In the multivariate analysis, the International Federation of Gynecology and Obstetrics (FIGO) stage and HPV genotypes maintained their relevant impact on pathologic complete response to chemoradiotherapy: FIGO stages IIIC1 and IIIC2 were associated with a 13-fold increased risk for the presence of metastatic lymph nodes compared with group 1 (p<0.001). HPV independent cervical cancers showed the highest risk for the development of macroscopic/stable disease (p=0.007), and persistence of metastatic lymph nodes (p=0.004) versus group 1, respectively.

CONCLUSIONS

This study showed that HPV status at diagnosis could be a relevant factor for clinical outcomes in locally advanced cervical cancer patients.