In some instances, patients present with growth of lung cancer on the inside of the airways (endobronchial).  For example, a tumor is growing inside the wall of the trachea or the bronchi.  When this occurs, patients often have symptoms like shortness of breath or persistent cough.  This situation can occur when patients have disease in their lung or even when this is the only site of disease.  The diagnosis is usually made by a pulmonologist who performs a direct visualization of the airways by bronchoscopy.  These nodules are missed on CT scans frequently because even when the block most of the airway –they are actually still quite small.  Here’s a representative view of an endobronchial lesion:

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   This type of tumor position is perfectly suited for a treatment approach called endobronchial high dose rate (HDR) brachytherapy.     This treatment approach utilizes a radioactive seed that is placed directly in contact with the tumor.  The length of contact and time of contact are determined by the size of the tumor and its location.  High dose rate refers to the use of a very hot radioactive seed that is usually made out of iridium.  The seed is attached to the end of a wire.  A very specialized machine houses the radioactive seed and wire.  It can then be programmed to feed the wire out of the machine and into the catheter for a predetermined length and time.  High dose rate procedures have basically replaced low dose rate procedures because the radiation dose can be delivered in a period of minutes rather than days if one used low dose radioactive sources. 

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   There some patients with early stage lung cancer that are not good candidates for standard lung surgery because of their underlying poor lung function.  A standard lung surgery typically involves removing the entire lobe of the lung that contains the cancer.  Unfortunately, for some patients with underlying COPD or emphysema – they can’t afford to lose a complete lobe of the their lung.  In this situation, some surgeons have performed more limited surgery including doing a “sub-lobar” resection.  The results for patients who have this limited surgical resection are not nearly as good as patients that have a complete lobectomy.  In some series, the incidence of local recurrence can be as high as 20-40% if only a limited surgery is performed.  The problem with these limited surgeries is that the surgeon often leaves microscopic disease behind along the edges of the surgical specimen.  In other tumor types, the surgical margins are evaluated carefully and more tissue is often resected if the margins are involved.  In lung cancer, evaluation the margins from the surgery specimen is more difficult, and the incidence of additional microscopic cells left in the area around the resection is probably quite high.  This probably explains while the recurrence rate for small tumors is quite low with a conventional lobectomy, and much higher when less tissue is removed in a sub-lobar resection.

   Brachytherapy means the use of locally placed radiation.  In this case, radioactive seeds are placed in and around the surgical suture line after the surgery is complete.  These seeds are sewed into the lung tissue or sewed into a mesh fabric that is then placed on the lung in the area that is at highest risk. 

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