# Metastasectomy

In oncology, metastasectomy is the surgical removal of metastases, which are secondary cancerous growths that have spread from cancer originating in another organ in the body.
In many cases, metastases are not treated surgically. There are two common reasons for this. Often, even with a successful surgery, the patient would have a poor prognosis. If the cancer is widely disseminated, it is likely that after the surgical removal of all known metastases, new ones will occur elsewhere. Sometimes, surgery itself has a low likelihood of success due to the location and/or extensiveness of the cancer. If complete surgical excision is feasible, however, removing both the primary cancer and its metastases may substantially improve the patient's prognosis. Some patients may even be cured.
The use of metastasectomy evolved in the field of liver resection for metastasised colorectal cancer, but has evolved to include resection of metastases from different primary cancers (such as breast cancer, melanoma, renal cell carcinoma, etc.) to the lungs, brain, and other organs. Not all of these applications are equally evidence-based, although with respect to some other primary cancers, metastasectomy may be underutilized.

## Liver metastasectomy
### Colorectal cancer

Among colorectal cancer patients, 15 to 25% will have liver metastases already when the colorectal cancer is discovered, and another 25 to 50% will develop them in the three years after resection of their primary cancer. Of patients who die from metastasised colorectal cancer, 20% have metastasis in the liver alone.
Surgical resection of liver metastases from colorectal cancer has been found to be safe and cost-effective. Reports from several large retrospective patient series suggest that it has a 5-year overall survival rate (5y OSR) averaging 30 to 40% and a 10y OSR around 16%, whereas the highest 5y OSR for modern chemotherapy regimens is only 9% (with FOLFOX). However, no randomized clinical trial has directly compared surgical management to chemotherapy or treatment with bevacizumab. Some have argued that the excellent results of liver metastasectomy for colorectal cancer are partially confounded by selection bias or reporting bias. Nevertheless, surgery for resectable metastases has become the standard of care, probably making such a trial (ethically) infeasible.
Previously, liver metastasectomy was limited to patients with less than four sites of metastasis in the liver, with a tumour-free margin of at least 1 centimetre, and no cancer elsewhere. These criteria have been challenged, however, and today the main criteria are a tumour-free margin and enough functional liver tissue (70%) preserved after surgery. Patients with initially unresectable liver metastases can be pre-treated with chemotherapy (this is called neoadjuvant chemotherapy). This pre-treatment causes the tumors to shrink, resulting in a larger proportion of liver tissue that is functional, with broader margins.
Preoperative evaluation involves imaging of the liver and its metastases, for example with ultrasound, computed tomography or magnetic resonance imaging. Positron emission tomography can be useful to check the entire body for metastases, although the test can be falsely normal with small lesions or preoperative chemotherapy. Baseline blood tests typically include liver function tests and tumour markers. During surgery, intraoperative ultrasound can aid the surgeon to find additional metastases.
A clinical risk score first proposed by Fong et al. is often used to assess the risk of recurrence after hepatic resection. The score assigns one point to each of the following:
* CEA level >200 ng/ml
* Disease-free interval from primary to metastasis <12 months
* Node-positive primary
* More than one liver metastasis
* Largest hepatic tumor >5 cm
The median survival for each score is:
| Fong Score | Median Survival |
| 0 | 74 months |
| 1 | 51 months |
| 2 | 47 months |
| 3 | 33 months |
| 4 | 20 months |
| 5 | 22 months |
Despite the score being highly predictive of long-term outcome, the clinical usefulness is often called into question because the chance of long-term survival is often enough to warrant surgery even in cases with high Fong Score. Some researchers have suggested that the Fong Score has become less useful with the advent of more effective neoadjuvant therapy.

## Pulmonary metastasectomy

Surgery is the mainstay of treatment for patients with isolated lung metastasis from colorectal cancer. Again, no randomized clinical trials exist, and the scientific evidence is weak, limited only to case series. The surgery can be performed with a low operative mortality.
For patients in whom the primary tumour is controlled and metastases are limited to the lung, criteria for eligibility include the technical resectability of the metastases and the general fitness and lung function reserve of the patient. If there are both liver and lung metastases, a resection of both can be attempted. In general, only 10% of patients with pulmonary metastases from colorectal cancer are resectable.
Blalock reported the first lung resection for metastasis from colorectal cancer in 1944.

## Footnotes

* 1 2 Tomlinson JS, Jarnagin WR, DeMatteo RP, et al. (October 2007). "Actual 10-year survival after resection of colorectal liver metastases defines cure". J. Clin. Oncol. 25 (29): 4575–80. doi:10.1200/JCO.2007.11.0833. PMID 17925551.
* 1 2 3 4 5 6 7 Khatri VP, Petrelli NJ, Belghiti J (November 2005). "Extending the frontiers of surgical therapy for hepatic colorectal metastases: is there a limit?". J. Clin. Oncol. 23 (33): 8490–9. doi:10.1200/JCO.2004.00.6155. PMID 16230676.
* ↑ Gazelle GS, Hunink MG, Kuntz KM, et al. (April 2003). "Cost-Effectiveness of Hepatic Metastasectomy in Patients With Metastatic Colorectal Carcinoma: A State-Transition Monte Carlo Decision Analysis". Ann. Surg. 237 (4): 544–55. doi:10.1097/01.SLA.0000059989.55280.33. PMC 1514476. PMID 12677152.
* ↑ Cummings LC, Payes JD, Cooper GS (February 2007). "Survival after hepatic resection in metastatic colorectal cancer: a population-based study". Cancer. 109 (4): 718–26. doi:10.1002/cncr.22448. PMID 17238180.
* ↑ Simmonds PC, Primrose JN, Colquitt JL, Garden OJ, Poston GJ, Rees M (April 2006). "Surgical resection of hepatic metastases from colorectal cancer: A systematic review of published studies". Br. J. Cancer. 94 (7): 982–99. doi:10.1038/sj.bjc.6603033. PMC 2361241. PMID 16538219.
* ↑ Sanoff HK, Sargent DJ, Campbell ME, et al. (June 2007). "N9741: Survival update and prognostic factor analysis of oxaliplatin (Ox) and irinotecan (Iri) combinations for metastatic colorectal cancer (MCRC)". J. Clin. Oncol., 2007 ASCO Annual Meeting Proceedings Part I. 25 (18S): 4067.
* 1 2 Fey MF, Rauch D (2001). "Metastasectomy--a direct therapeutic effect or an illusion due to patient selection?". Ther Umsch. 58 (12): 726–31. doi:10.1024/0040-5930.58.12.726. PMID 11797535.
* ↑ Begg CB, Cramer LD, Hoskins WJ, Brennan MF (November 1998). "Impact of hospital volume on operative mortality for major cancer surgery". JAMA. 280 (20): 1747–51. doi:10.1001/jama.280.20.1747. PMID 9842949.
* 1 2 Nordlinger B, Sorbye H, Glimelius B, et al. (March 2008). "Perioperative chemotherapy with FOLFOX4 and surgery versus surgery alone for resectable liver metastases from colorectal cancer (EORTC Intergroup trial 40983): a randomised controlled trial". Lancet. 371 (9617): 1007–16. doi:10.1016/S0140-6736(08)60455-9. PMC 2277487. PMID 18358928.
* ↑ Ekberg H, Tranberg KG, Andersson R, et al. (September 1986). "Determinants of survival in liver resection for colorectal secondaries". Br J Surg. 73 (9): 727–31. doi:10.1002/bjs.1800730917. PMID 3756436. S2CID 22309067.
* ↑ Hughes KS, Simon R, Songhorabodi S, et al. (August 1986). "Resection of the liver for colorectal carcinoma metastases: a multi-institutional study of patterns of recurrence". Surgery. 100 (2): 278–84. PMID 3526605.
* 1 2 Scheele J, Altendorf-Hofmann A (August 1999). "Resection of colorectal liver metastases". Langenbecks Arch Surg. 384 (4): 313–27. doi:10.1007/s004230050209. PMID 10473851. S2CID 33546325. Archived from the original on 2013-02-12.
* ↑ Poston GJ, Adam R, Alberts S, et al. (October 2005). "OncoSurge: a strategy for improving resectability with curative intent in metastatic colorectal cancer". J. Clin. Oncol. 23 (28): 7125–34. doi:10.1200/JCO.2005.08.722. PMID 16192596.
* ↑ O'Reilly DA, Chaudhari M, Ballal M, Ghaneh P, Wu A, Poston GJ (May 2008). "The Oncosurge strategy for the management of colorectal liver metastases - an external validation study". Eur J Surg Oncol. 34 (5): 538–40. doi:10.1016/j.ejso.2007.04.013. PMID 17560066.
* ↑ Wiering B, Krabbe PF, Jager GJ, Oyen WJ, Ruers TJ (December 2005). "The impact of fluor-18-deoxyglucose-positron emission tomography in the management of colorectal liver metastases". Cancer. 104 (12): 2658–70. doi:10.1002/cncr.21569. PMID 16315241.
* ↑ Wildi SM, Gubler C, Hany T, et al. (January 2008). "Intraoperative sonography in patients with colorectal cancer and resectable liver metastases on preoperative FDG-PET-CT". J Clin Ultrasound. 36 (1): 20–6. doi:10.1002/jcu.20408. PMID 17937421.
* ↑ Fong Y, Fortner J, Sun RL, Brennan MF, Blumgart LH (September 1999). "Clinical Score for Predicting Recurrence After Hepatic Resection for Metastatic Colorectal Cancer: Analysis of 1001 Consecutive Cases". Annals of Surgery. 230 (3): 309–18, discussion 318–21. doi:10.1097/00000658-199909000-00004. PMC 1420876. PMID 10493478.
* ↑ Schreckenbach T, Malkomes P, Bechstein WO, Woeste G, Schnitzbauer AA, Ulrich F (January 2015). "The clinical relevance of the Fong and the Nordlinger scores in the era of effective neoadjuvant chemotherapy for colorectal liver metastasis". Surg Today. 45 (12): 1527–34. doi:10.1007/s00595-014-1108-9. PMID 25563588. S2CID 23101155.
* 1 2 Pfannschmidt J, Dienemann H, Hoffmann H (July 2007). "Surgical resection of pulmonary metastases from colorectal cancer: a systematic review of published series". Ann. Thorac. Surg. 84 (1): 324–38. doi:10.1016/j.athoracsur.2007.02.093. PMID 17588454.
* ↑ Treasure T (November 2007). "Pulmonary Metastasectomy: A Common Practice Based on Weak Evidence". Ann R Coll Surg Engl. 89 (8): 744–8. doi:10.1308/003588407X232198. PMC 2173173. PMID 17999813.
* ↑ Saito H, Minamiya Y, Taguchi K, Nakagawa T, Ogawa J (January 2003). "[Surgical treatment for pulmonary metastases from colorectal cancer]". Kyobu Geka (in Japanese). 56 (1): 35–40. PMID 12607251.