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...
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Chapter 085. Neoplasms of the Lung (Part 11) 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 sputumor bronchial washing specimen but the chest radiograph appears normal (TXtumor stage), the lesion must be localized. More than 90% can be localized bymeticulous examination of the bronchial tree with a fiberoptic bronchoscope undergeneral anesthesia and collection of a series of differential brushings and biopsies.Often, carcinoma in situ or multicentric lesions are found in these patients. Currentrecommendations are for the most conservative surgical resection, allowingremoval of the cancer and conservation of lung parenchyma, even if the bronchialmargins are positive for carcinoma in situ. The 5-year overall survival rate forthese occult cancers is ~60%. Close follow-up of these patients is indicatedbecause of the high incidence of second primary lung cancers (5% per patient peryear). One approach to in situ or multicentric lesions uses systemicallyadministered hematoporphyrin (which localizes to tumors and sensitizes them tolight) followed by bronchoscopic phototherapy. Solitary Pulmonary Nodule and Ground Glass Opacity Occasionally, when an x-ray or CT scan is done for another purpose, apatient will present with an incidental finding of an asymptomatic, solitarypulmonary nodule (SPN, defined as an x-ray density completely surrounded bynormal aerated lung, with circumscribed margins, of any shape, usually 1–6 cm ingreatest 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 ofthe size requiring a biopsy for tissue. Approximately 35% of all such lesions inadults are malignant, most being primary lung cancer, while positive PET scan. At present, only two radiographic criteria are reliablepredictors of the benign nature of an SPN: lack of growth over a period >2 yearsand certain characteristic patterns of calcification. Calcification alone does notexclude malignancy. However, a dense central nidus, multiple punctate foci, andbulls eye (granuloma) and popcorn ball (hamartoma) calcifications are allhighly suggestive of a benign lesion. An algorithm for evaluating an SPN is shownin 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 thecharacteristic calcification patterns are absent, the following approach isreasonable. Nonsmoking patients 3 months for 1 year and then yearly; if any significant growth is found, ahistologic diagnosis is needed. For patients >35 years and all patients with asmoking history, a histologic diagnosis must be made, regardless of whether thelesion is PET positive or negative, since slow-growing cancers such as BAC canbe PET negative. The sample for histologic diagnosis can be obtained either at thetime of nodule resection or, if the patient is a poor operative risk, via video-assisted thoracic surgery (VATS) or transthoracic fine-needle biopsy. Someinstitutions use preoperative fine-needle aspiration on all such lesions; however,all positive lesions have to be resected, and negative cytologic findings in mostcases have to be confirmed by histology on a resected specimen. Much has beenmade of sparing patients an operation; however, the high probability of finding amalignancy (particularly in smokers >35 years) and the excellent chance forsurgical cure when the tumor is small both suggest an aggressive approach to theselesions. Since the advent of screening CTs, small ground-glass opacities(GGOs) have often been observed, particularly as the increased sensitivity ofCTs enables detection of smaller lesions. Many of these GGOs, when biopsied, arefound to be BAC. Some of the GGOs are semiopaque and referred to as partialGGOs, which are often more slowly growing, with atypical adenomatoushyperplasia histology, a lesion of unclear prognostic significance. By contrast,solid GGOs have a faster growth rate and usually are typical adenocarcinomashistologically.