Chapter 085. Neoplasms of the Lung (Part 11)

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Management of Occult and Stage 0 Carcinomas In the uncommon situation where malignant cells are identified in a sputum or bronchial washing specimen but the chest radiograph appears normal (TX tumor stage), the lesion must be localized. More than 90% can be localized by meticulous examination of the bronchial tree with a fiberoptic bronchoscope under general anesthesia and collection of a series of differential brushings and biopsies. Often, carcinoma in situ or multicentric lesions are found in these patients. Current recommendations are for the most conservative surgical resection, allowing removal of the cancer and conservation of lung parenchyma, even...

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Chapter 085. Neoplasms of the Lung (Part 11) Management of Occult and Stage 0 Carcinomas In the uncommon situation where malignant cells are identified in a sputum or bronchial washing specimen but the chest radiograph appears normal (TX tumor stage), the lesion must be localized. More than 90% can be localized by meticulous examination of the bronchial tree with a fiberoptic bronchoscope under general anesthesia and collection of a series of differential brushings and biopsies. Often, carcinoma in situ or multicentric lesions are found in these patients. Current recommendations are for the most conservative surgical resection, allowing removal of the cancer and conservation of lung parenchyma, even if the bronchial margins are positive for carcinoma in situ. The 5-year overall survival rate for these occult cancers is ~60%. Close follow-up of these patients is indicated because of the high incidence of second primary lung cancers (5% per patient per year). One approach to in situ or multicentric lesions uses systemically
administered hematoporphyrin (which localizes to tumors and sensitizes them to light) followed by bronchoscopic phototherapy. Solitary Pulmonary Nodule and "Ground Glass" Opacity Occasionally, when an x-ray or CT scan is done for another purpose, a patient will present with an incidental finding of an asymptomatic, solitary pulmonary nodule (SPN, defined as an x-ray density completely surrounded by normal aerated lung, with circumscribed margins, of any shape, usually 1–6 cm in greatest diameter). A decision to resect or follow the nodule must be made. Nodules of this size discovered in CT screening for lung cancer would also be of the size requiring a biopsy for tissue. Approximately 35% of all such lesions in adults are malignant, most being primary lung cancer, while
positive PET scan. At present, only two radiographic criteria are reliable predictors of the benign nature of an SPN: lack of growth over a period >2 years and certain characteristic patterns of calcification. Calcification alone does not exclude malignancy. However, a dense central nidus, multiple punctate foci, and "bull's eye" (granuloma) and "popcorn ball" (hamartoma) calcifications are all highly suggestive of a benign lesion. An algorithm for evaluating an SPN is shown in Fig. 85-2. Figure 85-2
Algorithm for evaluation of a solitary pulmonary nodule (SPN). CXR, chest x-ray; CT, computed tomography; PET, positron emission tomography. When old x-rays are not available, the PET scan is negative, and the characteristic calcification patterns are absent, the following approach is reasonable. Nonsmoking patients
3 months for 1 year and then yearly; if any significant growth is found, a histologic diagnosis is needed. For patients >35 years and all patients with a smoking history, a histologic diagnosis must be made, regardless of whether the lesion is PET positive or negative, since slow-growing cancers such as BAC can be PET negative. The sample for histologic diagnosis can be obtained either at the time of nodule resection or, if the patient is a poor operative risk, via video- assisted thoracic surgery (VATS) or transthoracic fine-needle biopsy. Some institutions use preoperative fine-needle aspiration on all such lesions; however, all positive lesions have to be resected, and negative cytologic findings in most cases have to be confirmed by histology on a resected specimen. Much has been made of sparing patients an operation; however, the high probability of finding a malignancy (particularly in smokers >35 years) and the excellent chance for surgical cure when the tumor is small both suggest an aggressive approach to these lesions. Since the advent of screening CTs, small "ground-glass" opacities ("GGOs") have often been observed, particularly as the increased sensitivity of CTs enables detection of smaller lesions. Many of these GGOs, when biopsied, are found to be BAC. Some of the GGOs are semiopaque and referred to as "partial" GGOs, which are often more slowly growing, with atypical adenomatous hyperplasia histology, a lesion of unclear prognostic significance. By contrast,
"solid" GGOs have a faster growth rate and usually are typical adenocarcinomas histologically.