Lung cancer is a major global cause of mortality, reportedly accounting for 1.7 million deaths each year. The most common form of lung cancer is non-small-cell lung cancer (NSCLC), and early-stage NSCLCs can often be surgically resected. Unfortunately, some patients still experience poor outcomes after surgical resection, prompting further research on the relationship between a patient's preoperative status and the likelihood of good postoperative outcomes.
Given this need for information, Dr. Shinya Tanaka from the Department of Rehabilitation and Prof. Naoki Ozeki from the Department of Thoracic Surgery, Nagoya University, and their colleagues decided to investigate. Previous studies had identified some risk factors for mortality after NSCLC resection, including sarcopenia, which is defined as the progressive loss of muscle mass and strength and predominantly occurs in older individuals. Another known risk factor for unfavorable postoperative outcomes is poor physical performance as measured with the 6-minute walking distance (6MWD) test, which involves measuring how far a patient can walk on a corridor in the span of 6 minutes.
To Dr. Tanaka and Prof. Ozeki, these past findings clearly pointed to "the importance of comprehensively assessing a patient's preoperative physical state in order to determine his or her risks of poor outcomes." However, no previous study of postoperative outcomes in patients with NSCLC had considered both sarcopenia and physical performance. Dr. Tanaka, Prof. Ozeki, and their colleagues therefore decided to conduct a study that addressed this gap in research. Their findings appear in a paper recently published in the Journal of Cachexia, Sarcopenia and Muscle.
The researchers analyzed data from 587 patients with NSCLC who underwent resection surgeries at Nagoya University Hospital between 2014 and 2017. They focused their analyses on determining how preoperative sarcopenia and exercise intolerance (defined as the inability to walk further than 400 meters on the 6MWD) influenced a patient's risk of mortality during the postoperative follow-up period, which lasted for 3.1 years on average.
The researchers' analyses showed that patients with preoperative sarcopenia had a 1.78-fold higher likelihood of death during follow-up than their peers without preoperative sarcopenia and exercise intolerance. Furthermore, patients with preoperative exercise intolerance had a 2.26-fold higher risk of death than patients without preoperative sarcopenia and exercise intolerance. However, the strongest effects emerged when sarcopenia and exercise intolerance coincided: patients who had preoperative sarcopenia and preoperative exercise intolerance had a 3.38-fold higher likelihood of death than patients who were free of sarcopenia and exercise intolerance prior to surgery.
These findings have important implications for the preoperative assessment of patients with NSCLC. In short, when oncologists are attempting to predict postresection prognoses, they should comprehensively consider a patient's physical status because variables like sarcopenia and exercise intolerance interact with each other to increase a patient's risk of mortality.
Dr. Tanaka and Prof. Ozeki hope that their findings "may contribute to the establishment of intervention methods to improve the prognoses of patients with NSCLC." More broadly, they hope that "more people will realize the importance of nutrition and exercise and try to lead healthier lives".
The paper, "Preoperative paraspinous muscle sarcopenia and physical performance as prognostic indicators in non-small-cell lung cancer," was published in Journal of Cachexia, Sarcopenia and Muscle on March 4, 2021, at DOI: 10.1002/jcsm.12691.
About Nagoya University, Japan
Nagoya University has a history of about 150 years, with its roots in a temporary medical school and hospital established in 1871, and was formally instituted as the last Imperial University of Japan in 1939. Although modest in size compared to the largest universities in Japan, Nagoya University has been pursuing excellence since its founding. Six of the 18 Japanese Nobel Prize-winners since 2000 did all or part of their Nobel Prize-winning work at Nagoya University: four in Physics - Toshihide Maskawa and Makoto Kobayashi in 2008, and Isamu Akasaki and Hiroshi Amano in 2014; and two in Chemistry - Ryoji Noyori in 2001 and Osamu Shimomura in 2008. In mathematics, Shigefumi Mori did his Fields Medal-winning work at the University. A number of other important discoveries have also been made at the University, including the Okazaki DNA Fragments by Reiji and Tsuneko Okazaki in the 1960s; and depletion forces by Sho Asakura and Fumio Oosawa in 1954.