This study is design to address, as follows:

1. correlation between fluorescence-based CFD measurements and tumor burden (primary tumor size, number of metastatic sites)
2. fluorescence-based CFD measurements and changes are related to tumor response. Based on the results of this study, the role of fluorescence-based CFD as a predictive biomarker for palliative chemotherapy is to be confirmed.

• It is important to check the response to chemotherapy. Currently, it is mostly evaluated as a radiologic response or, rarely the change of tumor markers.
• In the case of radiologic response tests at intervals of 6-8 weeks, there are cases where the economic burden and radiation exposure risk, additionally evaluation lesion is lack in a few case. Except for prostate cancer and ovarian cancer, the majority of carcinomas do not have cancer markers for assessing treatment response. Therefore, there is a need for biomarkers that can predict the response of anticancer treatment.
• In many studies, it has been reported that various types of circulating cell free DNA (CFD) are increased in various cancer types.
• Recently, a fluorescence based CFD method that can directly measure nucleic acids without a DNA extraction process has been developed, which makes testing simpler and more economical, and can be conveniently applied to cancer diagnosis and treatment response.
• This study is plan to evaluate the relationship between fluorescence-based CFD and treatment response in patients starting palliative chemotherapy, and check whether it can serve as a response evaluation for palliative chemotherapy.

Inclusion Criteria:

• Patients with histologically or cytologically confirmed initially metastatic or recurrent cancer who are expected to undergo primary palliative chemotherapy (patients who relapse after adjuvant chemotherapy before/after existing surgery can also be enrolled regardless of period)
• Patients with definitive tumor burden (Patients who do not have residual lesions due to metastasectomy are excluded. However, measurable lesions according to RECIST 1.1 are not mandatory, and evaluable lesions are possible)
• ECOG PS 0-2
• Adequate bone marrow, renal function, liver function to receive chemotherapy
• Patients with informed consent form

Exclusion Criteria:

• Patients with treating antibiotic treatment within 3 days of study enrollment due to overt or suspected infection
• Other serious illness or medical condition

Patients with histologically or cytologically confirmed initially metastatic or recurrent cancer who are expected to undergo primary palliative chemotherapy