The present retrospective study included 320 consecutive patients (age range, 23-97 years), with metastatic stage IV solid tumor who were referred to a single physician in a large community hospital-based radiation Οncology Department between May 2012 and October 2015. This minimal risk study was approved by the Good Samaritan Hospital Medical Center Institutional Review Board.

The charts and electronic records of all patients were assessed for previously validated prognostic factors, including ECOG performance status score (ECOG 0-1 vs. ECOG 2 vs. ECOG 3-4), primary tumor type (breast, prostate, kidney, lung or other), number of tumors (1-5 vs. ≥6), serum albumin (≥3.4 vs. 2.4-3.3 vs. ≤2.4 g/dl), location of metastases (bone only vs. liver vs. other) and age (>60 years vs. ≤60 years). Additionally, the relative contribution of baseline NLR (>4 vs. ≤4) at the time of consultation was explored.

Statistical analysis was performed with Stata 13.1 (StataCorp LP). The primary outcome was overall survival, defined as the time from the initial radiation oncology consultation to the date of death from any cause. Patients were included regardless of treatment received, and patients who were lost to follow-up were censored at the date of the last follow-up. Survival data were analyzed using the Kaplan-Meier method and summarized by median and 6-month survival. Differences in survival were assessed through the log-rank method. The association of individual variables with survival was assessed using the Cox proportional hazards model that was verified by tests of correlations over time with examination of residual plots. The Pearson χ² test was performed to determine whether there were baseline differences in variables that were associated with high or low NLR. Statistical tests were two-sided, and P<0.05 was considered to indicate a statistically significant difference.

The study population included 320 patients with distant metastases who were referred for radiation oncology evaluation, with 55% inpatient and 45% outpatient consultations. The median age was 68 years (interquartile range, 60-78 years), the median NLR was 4.4 (interquartile range, 2.8-7.2) and the median albumin was 3.4 g/dl (interquartile range, 2.8-3.8 g/dl). In terms of performance status, 39% of the patients were ECOG 0-1, 29% were ECOG 2 and 32% were ECOG 3-4. The most common types of cancer included non-small cell lung cancer (34%), breast (14%), small cell lung cancer (10%), prostate (9%), colorectal (6%), kidney (4%), endometrial (4%) and unknown primary (4%). With respect to the extent of the disease, 7% of the patients had only 1 site of active disease, 7% had 2 active tumors and 13% had 3-5 active tumors. Liver metastases were present in 21% of the patients and 16% had bone-only metastases. Only 12% of the patients had previously received ≥2 lines of palliative chemotherapy.

Among the 320 patients evaluated, 81% were treated with radiation therapy. Treatment was personalized to account for disease site and clinical status and goals of treatment. To summarize, the majority of the patients were treated with standard palliative regimens, most commonly 30 Gy in 10 fractions. Patients with a poor prognosis were either not treated or treated with short-course radiation (8-20 Gy in 1-5 fractions). Patients with limited brain metastatic disease (typically 1 to 4 brain metastases) were often treated with fractionated stereotactic radiotherapy (27 Gy in 3 fractions) or single-fraction stereotactic radiosurgery (21-24 Gy in 1 fraction). Patients with good performance status and oligometastatic disease (defined as ≤5 metastases) were treated with curative intent dose-intensive treatment regimens (12,13).

Systemic therapy was administered at the discretion of the treating medical oncologist and, depending on the diagnosis, consisted of chemotherapy, hormonal therapy, biologically targeted therapy, immunotherapy and/or supportive care.

The median survival for all patients was 6.7 months, with a median follow-up for surviving patients of 20.6 months. On univariate analysis, baseline NLR, number of tumors, ECOG performance status, serum albumin, primary tumor site, prior hospitalization within the last 3 months, liver metastases, bone-only and liver metastases, were found to be significant predictors of survival (Table I). The median survival for patients with an NLR of ≤4 was 9.3 months vs. 4.1 months for those with an NLR of >4 (Fig. 1). Age and number of prior palliative chemotherapy cycles were not found to be statistically significant in predicting survival.

On Cox regression analysis, the statistically significant predictors of survival included ECOG performance status (P<0.001), number of tumors (P<0.001), primary tumor site (P<0.001), albumin (P<0.001), liver metastases (P=0.013) and baseline NLR (P=0.042). Age (P=0.98), number of prior chemotherapy cycles (P=0.93), recent hospitalization (P=0.59) and bone-only metastases (P=0.79) were not found to be statistically significant in predicting survival (Table II).