Greatest surface diameter of a cancer, together with suspicion of regional node metastasis, forms the basis for prognosis through the clinical TNM staging system for many cancers. In oral cancer, however, surface size sometimes fails to correlate, or sometimes inversely correlates, with tumor aggressiveness. To shed light on the value of measuring size per se, 155 consecutive oral squamous cancers, treated by surgery, radiation, or a combination, were analyzed to find the degree of correlation between greatest surface measurement and pathologic nodal spread and control of cancer. In tumors less than 2 cm, size correlated with very few nodal metastases and with good prognoses; in tumors greater than 2 cm, increasing size did not show a corresponding increase in pathologic node metastasis or significantly worsening outcomes except for a few very large cancers invading adjacent structures. In conclusion, greatest surface diameter of an oral cancer, when greater than 2 cm, is an unreliable predictor of tumor behavior per se. A small pilot study suggests that tumor thickness may be a better predictor. A formal study of this is planned. of surface size alone as a guide to treatment planning, and how much surface measurement tells us about the chance of metastasis and the chance for cure.To define more precisely the value of surface size for one cancer, we undertook an analysis of the highly homogeneous squamous cancers of the oral cavity. Clinical experience with over 500 oral cancers led to the hypothesis that a greatest diameter (or size) of 2 cm divides oral cancers into those with a good prognosis (<2 cm) and those with only a fair prognosis (>2 cm). Division into size groupings greater than 2 cm does not indicate prognosis.
Materials and MethodsData from hospital charts at the University of Louisville School of Medicine teaching hospital were abstracted onto code sheets designed for the study. Of 186 consecutive patients treated from 1960 to 1981 for squamous cancer of the oral cavity, 155 had sufficient information to enable completion of data. All patients were treated by two surgical oncologists and two radiation oncologists whose training and practice emphasized head and neck oncology. Abstracting, coding, computerization, and tabulations from computer printouts were carried out by two fourth year medical students under the direction of the senior authors. Data items included: age, sex, intra-oral site (mobile tongue, floor of mouth, gum, buccal mucosa, retromolar space, palate) pathologic type, greatest diameter measurement of tumor, initial clinical staging by TNM-AJCC system, treatment, follow-up, pathologic evidence of neck node metastasis, and sites of recurrence.Success or failure of control of oral cancer was defined as freedom from cancer for at least 3 years after first di-