Solitary Colorectal Pulmonary Metastasis
ILLUSTRATIVE CASE SERIES
Solitary Colorectal Pulmonary Metastasis
By William B. Ershler, MD
A 61-year-old small business owner was seen in consultation for advice regarding management of a newly discovered pulmonary mass. Seven years previously, he had a 3.5 cm moderately differentiated adenocarcinoma of the sigmoid colon resected along with four regional nodes, all of which were negative for metastatic involvement. The tumor had been discovered at routine colonoscopy, and preoperative imaging studies, including CT scan of the abdomen and chest, were negative for apparent metastatic disease; carcinoembryonic antigen level (CEA) was mildly elevated at 3.8 ng/mL. After an uneventful recovery from his colon surgery, he was treated with eight 3-week cycles of capecitabine (750 mg/m2 po bid x 14 days every 21 days). Subsequent follow-up evaluations including periodic CT, screening chemistries, and occasional colonoscopies were not indicative of disease recurrence. However, at a recent follow-up visit, CEA titer was noted to be elevated (8 ng/mL). CT scan revealed a normal appearing abdomen and pelvis without lymphadenopathy or abnormalities in the liver or other organs. Colonoscopy also revealed no abnormality. However, CT of the chest revealed an oval-shaped density in the left lung measuring 3.5 cm in greatest diameter that had not been apparent on CT obtained 14 months previously. PET/CT identified the same lesion, but no others. A CT-guided lung biopsy revealed metastatic adenocarcinoma with histological and cytochemistry pattern consistent with colorectal primary. Kras mutation studies revealed no mutations at codons 12 and 13. The patient, otherwise healthy, non-smoker, and robust on physical examination, is referred for a second opinion regarding treatment options.
Discussion
This asymptomatic, otherwise healthy middle-aged man has what appears to be metastatic colon cancer, presumably from a primary lesion resected 7 years previously. There are several aspects of this case that are unusual and worthy of note.
First, 7 years ago after the original resection, the decision to treat with adjuvant chemotherapy for clinical stage II disease presumably was based on an insufficient number of resected nodes (only four, well below the number that confers confidence of adequate staging). Nonetheless, there has been a resurfacing of enthusiasm for adjuvant treatment for stage II disease these days, based primarily upon the findings from the QUASAR study demonstrating modest but significant improvement in survival for patients treated with fluorouracil and folinic acid compared to placebo.1
Second, both the long disease-free interval and the pattern of spread must be considered unusual. Certainly, the primary physicians were aware of this, and pursued other explanations, including colonoscopy and CT and PET/CT imaging studies. Perhaps the long disease-free interval relates to more indolent tumor growth characteristics, possibly influenced by adjuvant chemotherapy. But, appearing as an isolated focus in the lung would seem distinctly uncommon. However, it is not completely rare. In fact, by carefully examining a fairly large database of patients with colorectal cancer, Tan and colleagues found the incidence of isolated lung without liver metastases in patients with colon cancer to be approximately 6%, compared with 12% for patients with primary rectal cancer.2 Thus, although certainly less common than with rectal cancer, isolated recurrence in the lung without liver involvement should not be considered rare.
However, despite this, there basically are no data derived from randomized studies to guide subsequent treatments. This is not to say there have not been sufficient published reports in the surgical literature describing outcomes for patients after pulmonary metastasectomy. Pfannschmidt and colleagues reported on outcome factors for pulmonary resection in metastatic colorectal cancer.3 Their systematic review included 15 articles and 1539 patients. Overall 5-year survival after complete surgical resection was 40% to 68%. Five-year disease-free survival ranged from 19.5% to 34.4%. For patients having both hepatic and pulmonary metastasectomy, overall survival was between 31% and 60.8%; estimated disease-free survival at 3 years was 8%. Completeness of resection was the most important prognostic indicator. Kanemitsu and colleagues developed a predictive model for estimating long-term outcome.4 Primary histopathology, hilar or mediastinal lymph node involvement, number of metastases, preoperative carcinoembryonic antigen level, and the presence of extrathoracic disease were factors used in the calculation of a clinical risk score, which was highly predictive of long-term outcome.
For the patient under discussion, it would seem that the most logical next step would be surgical excision. After the long disease-free interval, the solitary nature of the disease recurrence as defined by PET/CT and his overall performance status, the expectation is that he would have a good outcome in terms of protracted disease-free survival. For me, the question is not whether to proceed with surgery, but what to do after recovery. Although there is no trial-derived evidence for chemotherapy in this second adjuvant setting, studies are now underway employing adjuvant chemotherapy after liver metastases resection.5 These findings may ultimately be applicable to the post-pulmonary metastastectomy adjuvant therapy question. Until such data are available, recommendations must be based on best clinical judgment. In this case, my recommendation would be to proceed to surgery and upon recovery a full course of oxaliplatin-based adjuvant chemotherapy.
References
1. Gray R, et al. Adjuvant chemotherapy versus observation in patients with colorectal cancer: A randomised study. Lancet 2007;370:2020-2029.
2. Tan KK, et al. How uncommon are isolated lung metastases in colorectal cancer? A review from database of 754 patients over 4 years. J Gastrointest Surg 2009;13:642-648.
3. Pfannschmidt J, et al. Surgical resection of pulmonary metastases from colorectal cancer: A systematic review of published series. Ann Thorac Surg 2007;84:324-338.
4. Kanemitsu Y, et al. Preoperative probability model for predicting overall survival after resection of pulmonary metastases from colorectal cancer. Br J Surg 2004;91:112-120.
5. Machida N, et al. Feasibility of mFOLFOX6 as the adjuvant treatment after curative resection of metastases from colorectal cancer in Japanese patients. Int J Clin Oncol 2012 Feb 25 [Epub ahead of print].
A 61-year-old small business owner was seen in consultation for advice regarding management of a newly discovered pulmonary mass. Seven years previously, he had a 3.5 cm moderately differentiated adenocarcinoma of the sigmoid colon resected along with four regional nodes, all of which were negative for metastatic involvement.Subscribe Now for Access
You have reached your article limit for the month. We hope you found our articles both enjoyable and insightful. For information on new subscriptions, product trials, alternative billing arrangements or group and site discounts please call 800-688-2421. We look forward to having you as a long-term member of the Relias Media community.