Editorial comment

History and present status of pulmonary metastasectomy in colorectal cancer

Clinical practice with respect to metastatic colorectal cancer differs from the other two most common cancers, breast and lung, in that routine surveillance is recommended with the specific intent of detecting liver and lung metastases and undertaking liver and lung resections for their removal. We trace the history of this approach to colorectal cancer by reviewing evidence for effectiveness from the 1950s to the present day. Our sources included published citation network analyses, the documented proposal for randomised trials, large systematic reviews, and meta-analysis of observational studies. The present consensus position has been adopted on the basis of a large number of observational studies but the randomised trials proposed in the 1980s and 1990s were either not done, or having been done, were not reported. Clinical opinion is the mainstay of current practice but in the absence of randomised trials there remains a possibility of selection bias. Randomised controlled trials (RCTs) are now routine before adoption of a new practice but RCTs are harder to run in evaluation of already established practice. One such trial is recruiting and shows that controlled trial are possible.

Thoracic lymphatic involvement in patients having pulmonary metastasectomy: incidence and the effect on prognosis

Mediastinal and hilar lymph node involvement are rarely reported in the literature concerning pulmonary metastasectomy. The first problem is to determine with accuracy the incidence and location of thoracic lymph node involvement in patients with lung metastases. Determination of the impact on survival of this type of lymphatic spread may contribute to assessing whether metastatic nodal disease identified preoperatively is an absolute contraindication to metastasectomy. Systematic mediastinal lymph node dissection has revealed a statistically significant difference in survival between patients with lymph node involvement and those without lymph node metastases. Videomediastinoscopy to identify involved mediastinal lymph nodes can be safely performed and may have a role in a more accurate staging of the metastatic disease. The authors conclude that attention should be paid to ensuring that we do not operate on patients in whom we will leave behind diseases that we cannot reach. The discovery of mediastinal lymph node involvement may also influence decisions with respect to postresection adjuvant therapy.

Surgery for lung metastases from colorectal cancer: the practice examined

Operations to remove metastases in the lung have become commonplace. In this article, I give a highly critical perspective of a practice that has grown without a secure evidence base, notwithstanding more than 500 articles on the subject. The objectives are mixed and sometimes unclear. The reports are generally in the form of Kaplan-Meier survival analyses but, when challenged on the expected benefit for individuals, clinicians tend to retreat to claims for palliation rather than for 'cure'. Yet the reports include no symptom checklists, quality-of-life measures or patient-reported outcomes. I see at least four distinguishable contexts, defined by cancer types, which deserve to be considered separately: sarcoma; testicular and germ cell tumors; cancers traditionally seen as having an 'oligometastatic' pattern of behavior, such as kidney and thyroid; and the more common solid cancers, such as colorectal and breast cancer. Most surgical series group them together with a tail of one, two or three instances of the less common cancers. The inclusion in these series of all cancer types operated upon adds nothing to knowledge on cancers with low numbers and complicates the analysis for the more common ones. In this article, I will confine the discussion for the main part to colorectal cancer, which is the most common cancer in which pulmonary metastasectomy is practiced.