An increase in the peripheral lymphocyte-to-monocyte ratio after primary site resection is associated with a prolonged survival in unresectable colorectal carcinoma

• Published in: Surgery today (Tokyo, Japan) Vol. 50; no. 6; pp. 604 - 614
• Main Authors: Ichikawa, Nobuki, Homma, Shigenori, Yoshida, Tadashi, Mitsuhashi, Tomoko, Iijima, Hiroaki, Ogasawara, Kazuhiro, Kazui, Keizo, Kamiizumi, You, Kawamata, Futoshi, Taketomi, Akinobu
• Format: Journal Article
• Language: English
• Published: Singapore Springer Singapore 01-06-2020
• Subjects: Medicine; Medicine & Public Health; Original Article; Surgery; Surgical Oncology; Primary site tumor; Metastatic; Excision; Colorectal cancer; Lymphocyte/monocyte ratio
• ISSN: 0941-1291; 1436-2813
• DOI: 10.1007/s00595-019-01927-1

Purpose
The prognostic benefits of primary tumor resection in patients with unresectable distant metastatic colorectal cancer remain unclear. A high pre-treatment lymphocyte-to-monocyte ratio (LMR) was previously shown to be associated with a better prognosis. We assessed whether or not primary tumor resection was associated with an improved survival if the peripheral lymphocyte-to-monocyte ratio increased after primary site resection.
Methods
The survival in 64 and 59 patients with and without primary tumor resection, respectively, was retrospectively compared. After resection, the survival in 39 patients with a postoperatively increased LMR (LMR-increase) and 25 patients with a decreased LMR (LMR-decrease) was compared.
Results
Primary tumor resection prolonged the median survival more frequently in cases of non-differentiated adenocarcinoma, obstructive symptoms, high serum albumin levels, and no lymph-node metastasis than in others. Cox regression showed that the potential independent prognostic variable was non-resection of the primary lesion. After resection, the median survival in the LMR-increase vs. LMR-decrease groups was significantly different (27.3 vs. 20.8 months). There were no marked differences in patient background characteristics between the groups, except for in the number of pre-operative peripheral blood lymphocytes. The resected specimens showed significantly lower CD8
+
:CD163
+
invading leukocyte ratios in the LMR-increase group than in the LMR-decrease group.
Conclusions
Primary tumor resection in patients with unresectable metastatic colorectal cancer may be associated with an improved survival, especially when the LMR is increased after primary tumor resection.