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Screening for cancer is a popular issue for debate because few, if any, evaluations of the screening process have been conducted on a long-term prospective basis with use of concomitant, unscreened controls. We have found that screening of high-risk persons for presymptomatic lung cancer will identify patients with cancer in the upper and lower respiratory passages. Randomly selected patients enrolled in the Mayo Lung Project have undergone sputum cytologic and chest roentgenographic screening at four-month intervals and were compared with randomly selected matched control subjects who were not intensively screened. The search for upper airway tumors in the head and neck region was instigated by abnormal findings on sputum cytology in 12 screened patients. In the same period, 12 other screened patients with abnormal results of sputum cytology were found to have roentgenographically "occult" lung cancer. This finding emphasized the importance of the otorhinolaryngologic examination in screening programs for airway cancer. It is also important to emphasize that sputum-negative patients may have obvious, symptomatic tumors of the upper aerodigestive tract that can be easily diagnosed by those who are skilled in examining this area. Contrary to our expectation, there is no definitive evidence that screening has reduced mortality from either upper or lower airway cancer.

Hematoporphyrin is preferentially concentrated by cancer tissue and therefore is a potentially useful chemical marker. This report demonstrates the effectiveness of a photoelectric hematoporphyrin fluorescence detector used simultaneously with flexible fiberoptic bronchoscopy as a means of detecting and localizing bronchogenic carcinoma. The detector generates an audio signal when fluorescence is within the visual field of the bronchoscope. Of interest is that an audio signal was generated which indicated hematoporphyrin fluorescence in areas where no mucosal abnormality had been seen. These areas proved to be carcinoma in situ.

Hematoporphyrin derivative used in conjunction with the Mayo Clinic bronchofiberscopic fluorescence detection system allows accurate localization of radiographically occult early squamous cell carcinoma. Thirteen tumors were localized in 10 patients with radiographically occult lung cancer. Six were in situ with or without microinvasion and were also bronchoscopically occult. Localization of these 6 tumors was expedited by the use of hematoporphyrin derivative and the bronchoscopic fluorescence detection system. Hematoporphyrin-derivative fluorescence was not specific for carcinoma and was also detected in areas of moderate and marked squamous cellular atypia. Thus, although detection of hematoporphyrin-derivative fluorescence suggests the presence of cancer, proof depends on histologic or cytologic confirmation.

Bronchoscopic cryotherapy of localized endobronchial tumors can be applied in selected patients who are not candidate for other traditional therapy. Twenty-eight patients were treated on 60 occasions with a closed liquid nitrogen system and a long insulated probe that was specifically designed to be used through an open ventilating bronchoscope. The conditions of 15 patients (54%) was improved, as judged by local tumor control, decreased bleeding, or improved airway patency. Fatal complications that could be ascribed to cryotherapy occurred in 2 of the 60 treatments (3%). Two patients have experienced complete control of squamous cell cancers four years and five years nine months after cryotherapy.

During the past 10 years, 54 patients, all men, were found to have roentgenographically occult lung cancer. The mean age was 61 years (range 45 to 76 years). All patients had abnormal findings on sputum cytologic study (carcinoma in 41 patients and squamous cell atypia in 13). The cancer was localized by bronchoscopy in all patients (range one to five examinations, mean 1.5). Seventy-five percent of the tumors were localized within 169 days of the abnormal sputum cytologic examination. Pulmonary resection for cure was performed in all patients: lobectomy in 38, pneumonectomy in nine, and bilobectomy in seven. Operative mortality was 5.6% (three patients). Fifty-eight cancers were resected, all squamous cell carcinomas (two had a component of large cell cancer). Tumor TNM classification (AJC) was TIS N0 M0 in 19 patients, T1 N0 M0 in 25, T1 N1 M0 in five, T2 N1 M0 in four, and T3 N0 M0 in one. Overall 5 year actuarial survival rate (lung cancer deaths only) was 90%. Five-year survival rate for the 44 patients with TIS N0 M0 and T1 N0 M0 neoplasms was 91%. Currently, 21 patients have died, but only 10 of lung cancer. Subsequent additional lung cancer developed in 12 patients (22%). Eleven of these patients had a second primary squamous lung cancer, six of which again were occult. We conclude that patients with occult lung cancer have a strong likelihood of long-term survival if treated early. Close surveillance is indicated because of the high incidence of a second primary lung cancer.