Tokushukai Medical Group

Treatment of Disease

Treatment of Disease

Respiratory Surgery Disease:Metastatic Lung Tumor

Different from Primary Lung Cancer

Lung is made of fine stitch structure to inhale oxygen necessary for a body and works as filter of blood. Blood flow out from heart courses through a body and returns to lung, but in case if there is cancer somewhere in a body so that cancer cell drops in blood then it flows into lung by blood stream, it is stuck in lung and propagates over there. This is the formation of metastatic lung tumor. (Fig.1) Therefore, to comply with lung metastasis, it is necessary that cancer cell has progressed already to drop in blood. Lung metastasis may not occur in early stage cancer. Possibility of lung metastasis is getting higher in advanced cancer.

Fig. 1; Primary tumor and metastasis pathway of metastatic lung tumor (from HP of Japanese Respiratory Society)

Cancers which metastasize to lung are, cancer of colon/rectum (bowel cancer), breast cancer, cancer of kidney, cancer of uterus, cancer of head and neck, malignant tumor of osseocartilaginous, bladder cancer, stomach cancer, cancer of esophagus, liver cancer, cancer of pancreas, and cancer of ovary. Every cancer may possibly metastasize to lung. There is a case where lung cancer metastasizes to lung, but the point is “Lung cancer will not be developed by metastasized cancer of uterus”. “Lung cancer” is developed by lung consisting tissue become cancerous so that it is called as “Primary lung cancer”. On the other hand, cancer which breast cancer is metastasized to lung is called as “lung metastasis from breast cancer (metastatic lung tumor)”, so that it is separately considered from primary lung cancer. Talking in similitudes, children bone in the USA from Japan native parents will not be Caucasian (He/She can get US citizenship though). That is to say, tissue metastasized to lung from breast cancer remains as breast cancer tissue, it will never change to lung cancer tissue.

There is a case where even no metastatic tumor exists in the first surgical operation for primary focus, metastatic lung tumor comes out few months to few years later from the operation. The “recurrence”. But since metastatic tumor is developed by cancer tissue dropped out from primary focus, this means that “cancer tissue has already been metastasized to lung at the time of surgical operation. And because of the metastasized cancer tissue is so small that is unable to identify by image examination.” This is not a “missed” nor “medical malpractice”. This is the limit of current medical technology level. It may be sound like excuse, but invisible thing is invisible.

For example (please excuse for often talking in similitudes), lets observe bread which is past the use-by date every day. After a while, fungus appears and gradually spread across the bread. In this case, does fungus appear just when you find them? That is not the case for sure. That fungus has existed in bread away back you find them, but it was just “invisible” at that time. Metastatic lung tumor is the similar thing. Micro metastatic focus which was invisibly small focus at the time of operation, has grown up large so that it is diagnosed as “recurrence” when its size becomes large enough which image examination can find. Therefore, it is necessary to have periodical health check even after the definitive surgery to evaluate whether or not there is no recurrence.

Almost of all are discovered at examination.

Usually, metastatic tumor has no subjective symptom in early stage. Most of them are found at examination. When disease condition advance, symptom like Cough, bloody sputum, breath shortness, or feeling of smothering, will appear.

Diagnose with bearing the possibility of primary or benign tumor in mind.

The disease is diagnosed with Chest X-Ray or CT examination. When many tuberous shadows has found in lung, possibility of metastatic tumor is strongly considered, and when person had been affected by malignant tumor before, the most specious is the lung metastasis but for the person had never been affected by malignant tumor before, it is necessary to seek where is the primary organ (or where has cancer tissue been metastasized from). But in case the shadow of lung is only one,diagnosis should be done carefully with bearing the possibility of not only metastatic lung tumor but also primary lung cancer, inflammatory nodules, benign tumor, so on, even for the person who had been affected by malignant tumor. In case when determination is difficult, there is a case where tissue examination is made by bronchoscope (bronchial Camera) or thoracoscopic surgery.

Surgery becomes adequate if Thomford Standard is fulfilled.

Treatment plan is different for each primary tumor. Most of the case, they are advanced cancer, so that selecting chemotherapy regimen (anti-cancer agent) is common. Existence of lung metastasis means that the cancer cell has already been spread out to entire body from primary organ, so that even with cutting off visible pathological lesion by image or applying the radiation may not change status so much, as never-ending story since invisible small pathological lesion may come up one after another. Surgery or radiation therapy is just a “local treatment”, so that it does not fit to the “lung metastasis” condition. On the other hand, chemotherapy treatment (anti-cancer agent) may affect to metastatic tumor as medicine flows around entire body by blood stream. Anti-cancer drug is different in effective drug variation or dosage method for each primary tumor. Details should be consulted with specialist physician.

“Primary selection for metastatic tumor treatment is chemotherapy regimen (anti-cancer drug)” has explained afore, but there is an exception. Depend on kinds of primary organs, when several conditions, like to fulfill the requirement of Thomford Standard (Chart 1) , every metastatic focuses are located at resectable area, interval time is long enough from initial surgery of primary focus to its recurrence and metastasis, there is no other pathological change occur while observing of the disease in few months passed from when metastatic focus shows up, has been cleared up, resecting lung metastatic focus can expect the complete cure, so that surgery or radiation treatment is conducted.

  • Patient can endure surgical operation
  • Primary focus has been controlled.
  • There is no other recurrence or metastasis exists other than lung.
  • Metastasis focus is limited in one-lung.

Chart 1. Thomford Standard

Surgery of metastatic tumor commonly done by partial excision which hollows only tumor part. Advanced primary lung cancer may metastasize lymphatically so that hollowing only primary focus may left lymphatic node and recur disease from there, so that common standard resection method is to cut off both primary focused lung lobe and lymphatic node together. But in metastatic tumor, lymphatic metastasis from metastatic focus might not occur in most of the case, it is sufficient to cut off metastatic focus only.

But there is a case where it is unexpectedly difficult to cut small lung metastasis. It is relatively easy to find out disease lesion in 1cm size or over, near the surface of lung, during the surgery with touching it, but it is not that easy to identify pathological lesion with few mm in size at relatively deep inside lung by examination in touch. Without knowing metastasis location where it is, it becomes unable to cut off only pathological change so that in worst case scenario, whole lung lobe where metastasis exists. If possible, we need to avoid such case, it becomes necessary to mark metastasis part area prior to the surgery. While CT examination is conducting, there is a method which punch in small fish hook like marker to lung, or pigment is injected to the cut off area by bronchial camera. (Surgical physician will select which method is used.)

After the resection of metastatic tumor, it is necessary to observe the course carefully and strictly whether new metastasis appear again. So that course may be observed while performing chemotherapy. In case when it is recurred, re-examine the possibility of resection surgery and if possible, reoperation is conducted.