Family history of cancer and risk of second malignancies in young cancer patients in Trieste, Italy.

We carried out a cohort study in the Italian province of Trieste (2001 population, 242,000) to ascertain whether the risk of a subsequent primary cancer among 265 individuals diagnosed with a first malignancy at ages up to 25 years between 1971 and 1993 differed from that in the general population and to evaluate the effect of cancer family history, quantified by the family risk index (FRI), on the occurrence of second primaries. During the follow-up (median duration = 10 years; 25th-75th percentile = 2-16), 15 cohort members developed a second cancer vs. 1.60 expected for a standardized incidence ratio (SIR) of 9.4 (p < 0.0001). The overall SIR fell to 4.7 (p = 0.004) after excluding the 8 patients with well-known cancer-predisposing conditions (SIR = 300.0; p < 0.0001) and the 50 with a positive family history (FRI >/= 1.0) of malignant tumors (SIR = 20.0; p < 0.0001). Among 114 patients treated with radiotherapy and chemotherapy for their first neoplasms and not affected by predisposing disorders, 23 with a positive family history of cancer showed a 6.4-fold excess risk of second primaries (p = 0.008) compared with 91 with a negative history (FRI < 1.0). It is imperative that clinicians carefully and regularly evaluate cancer family history of young patients with malignancies. This would enable them to identify possible individual and familial features in patients at higher risk of multiple primaries and to adopt more suitable preventive and therapeutic measures.

Malignant tumors in first-degree relatives of cancer patients aged 0-25 years (province of Trieste, Italy).

To determine whether the occurrence of first and second primary malignancies in first-degree relatives of cancer patients aged 0-25 years (probands) differed from that in the general population, a cohort study was carried out on 860 relatives of 265 probands living in the province of Trieste, Italy. During the follow-up period (median duration = 28 years, 25th-75th percentile = 20-34), the relatives developed 103 first primary cancers vs. 88.9 expected for a standardized incidence ratio (SIR) of 1.2 (p = 0.2). Significantly elevated risks were found for melanoma in the parents of probands aged 15-25 years with melanoma (SIR = 15.0, p = 0.002), for hemolymphatic malignancies in the fathers of probands aged 0-14 years with brain tumors (SIR = 13.3, p = 0.0005) and for hemolymphatic cancers in relatives as a whole of probands aged 15-25 years with lymphomas (SIR = 4.5, p = 0.01). During the follow-up period, 7 relatives with a first primary cancer had a subsequent malignancy vs. 4.2 expected for an SIR of 1.7 (p = 0.3). Our results indicate that young cancer patients per se should not to be considered as a factor that usually increases the risk of developing malignant tumors among their first-degree relatives, except when a known cancer family syndrome or predisposition is recognized.