Naruki Nishimatsu

Tumor-doubling time and onset of pulmonary metastasis from adenoid cystic carcinoma of the salivary gland

Adenoid cystic carcinoma (ACC), an uncommon malignancy in the head and neck region, invades diffusely and often metastasizes to the lung, although the growth rate is very slow. A retrospective study was conducted in 30 patients with ACC to ascertain the frequency of pulmonary metastasis, the doubling time of metastatic tumor deposits, and the time of onset for pulmonary metastasis. The following results were obtained: (1) Of 30 patients with ACC, 21 had pulmonary metastases (4 initially and 17 during observation), 7 were free of metastases but have not been observed for 5 years, and 2 were free of metastases for more than 5 years but less than 10 years after the initial treatment. The cumulative metastasis rate at 5 and 10 years for this group of patients was 70% and 100%, respectively. (2) Patients with T1 or T2 tumors that have a tubular or cribriform histopathologic pattern showed pulmonary metastases about 20 months later than those with T3 or T4 tumors and a solid pattern. However, the final metastasis rate did not differ between the 2 groups after a long period. (3) The tumor doubling time of the metastatic deposits of ACC was 86 to 1064 days with an average of 393 days, which was much longer than that of most other malignant neoplasms reported previously. (4) The time of onset of pulmonary metastasis was calculated to be much earlier (average of 227 months) before the first visit. These findings suggest that the treatment method for ACC should be chosen with the consideration that many of the patients may have occult pulmonary metastases at the time of their initial evaluation.

Criteria for diagnosing lymph node metastasis from squamous cell carcinoma of the oral cavity: A study of the relationship between computed tomographic and histologic findings and outcome

PURPOSE This retrospective study was conducted to determine the relationship between the computed tomographic findings for cervical lymph nodes (LN), histologic findings, and outcome in patients with squamous cell carcinoma of the oral cavity who underwent radical neck dissection. PATIENTS AND MATERIALS Sixty-six patients were analyzed. Of these 66 operations, 43 were immediate therapeutic dissections in clinically N+ necks, and 23 were subsequent therapeutic dissections in patients whose necks were initially node free but progressed to positive nodes during observation. RESULTS When the size criterion (area of the axial section) of nodal metastasis depicted on the scan of 45 mm2 was selected, almost 78% of LN were diagnosed consistent with the histologic diagnosis. As the size of the LN increased, the frequency of extranodal invasion also became higher, whereas patients with the higher histologic grades of malignancy often showed neck metastases with extranodal invasion in the early stage. Patients having LN smaller than 100 mm2, or without extranodal invasion, showed good outcome, whereas those having LN 100 mm2 or larger, with extranodal invasion, showed extremely poor outcome. CONCLUSIONS These findings indicate that it is possible to delay neck dissection in node-free patients until neck disease is diagnosed with timely CT examination, although great caution is necessary, especially in those with a high histologic grade of malignancy.

Establishment and characterization of a human adenoid cystic carcinoma line of the salivary gland which is serially transplantable and spontaneously metastasises to the lung in nude mice

Adenoid cystic carcinoma (ACC) is a rare malignant tumour of the head and neck occurring in the salivary glands. We established a human ACC line which is serially transplantable in nude mice and designated it as KOA-1. The KOA-1 tumour doubled in 9.3 days and retained the histological characteristics of a solid pattern of ACC even after 22 serial passages. The KOA-1 metastasised to the lung when transplanted subcutaneously into the back. This tumour line may serve as a useful model for exploration of the biological behaviour and treatment of human ACC.