The impact of the location, incidence and distribution of lung metastases in primary colorectal and renal cell cancer patients on prognosis: a retrospective observational study

Background: Patients with distant metastases have an unfavourable prognosis, but patients with isolated pulmonary metastases should generally not be considered hopeless. Complete resection of metachronous and solitary metastases leads to prolonged survival; however, the influence of the location, distribution and bilaterality of pulmonary metastases needs to be investigated further. This article aimed to investigate the role of the distribution of lung metastases in primary colorectal and renal cell cancer patients on prognosis. Methods: We retrospectively investigated the prognosis of patients with pulmonary metastases and colorectal or renal cell carcinoma, defined as the survival time of patients with different metastases. The types of metastases were unilobar, multilobar, unilateral, bilateral, diffuse, synchronous, or metachronous. The secondary outcome of this study was differences in prognosis according to additional criteria. Results: Patients with metachronous metastases had significantly greater median survival than patients with synchronous metastases. There was a statistically significant difference in median survival between patients with unilateral (better survival) and patients with bilateral (worse survival) lung metastases. In patients with renal cell carcinoma, a statistically significant difference in median survival time was detected for patients with unilateral metastases. A significantly longer median survival time was observed in patients without diffuse metastases. A significantly greater median survival time was detected in patients with no thoracic nodal involvement. Moreover, there was no statistically significant difference in the median survival time for patients with colorectal versus renal cell carcinoma in general or for those with lung metastases. No statistically significant difference in median survival time was detected for patients according to single or multiple lung metastases, additional tumours or metastases during disease, the distance of residence from a specialized clinic in Coburg, sex, smoking or adipocytes, multimorbidity, immunosuppression or different cancer treatments. Conclusions: For a minority of patients, pulmonary resection is a chance for prolonged survival. The perioperative mortality rate after metastasectomy is less than five percent. Patients with metachronous and unilateral lung metastases should be evaluated for surgery. Patients with diffuse metastases or lymph node involvement have a significantly shorter median survival time. Decision-making should be interdisciplinary.